Patent application title: POLISHING MEMBER AND SEMICONDUCTOR MANUFACTURING METHOD
Inventors:
IPC8 Class: AB24B3720FI
USPC Class:
451 41
Class name: Abrading abrading process glass or stone abrading
Publication date: 2017-08-17
Patent application number: 20170232573
Abstract:
A polishing member according to an embodiment includes a first polisher,
a second polisher, and a third polisher. The first polisher is capable of
rubbing a target surface. The second polisher is surrounded by the first
polisher. A hole is located along an edge of the second polisher between
the first polisher and the second polisher. The third polisher connects
the first polisher and the second polisher.Claims:
1. A polishing member comprising: a first polisher capable of rubbing a
target surface; a second polisher surrounded by the first polisher, the
second polisher having a hole along an edge of the second polisher
between the second polisher and the first polisher; and a third polisher
connecting the first polisher and the second polisher.
2. The member of claim 1, wherein a smallest width of the third polisher is smaller than a largest width of the second polisher.
3. The member of claim 1, wherein the hole has a substantially horseshoe shape in a planar view.
4. The member of claim 2, wherein the hole has a substantially horseshoe shape in a planar view.
5. The member of claim 1, wherein the hole has a substantially spiral shape in a planar view.
6. The member of claim 2, wherein the hole has a substantially spiral shape in a planar view.
7. The member of claim 1, wherein the first polisher has a peripheral edge in a substantially circular shape and rubs the target surface in a range of the first polisher between a first circle concentric with the first polisher and a second circle having a larger diameter than that of the first circle and being concentric with the first polisher, a plurality of the holes are located at intervals in at least one of a radial direction and a circumferential direction of the first polisher to intersect with a circle being concentric with the first polisher and having an arbitrary diameter equal to or larger than the diameter of the first circle and equal to or smaller than the diameter of the second circle, and a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the through holes, respectively.
8. The member of claim 2, wherein the first polisher has a peripheral edge in a substantially circular shape and rubs the target surface in a range of the first polisher between a first circle concentric with the first polisher and a second circle having a larger diameter than that of the first circle and being concentric with the first polisher, a plurality of the holes are located at intervals in at least one of a radial direction and a circumferential direction of the first polisher to intersect with a circle being concentric with the first polisher and having an arbitrary diameter equal to or larger than the diameter of the first circle and equal to or smaller than the diameter of the second circle, and a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the through holes, respectively.
9. The member of claim 3, wherein the first polisher has a peripheral edge in a substantially circular shape and rubs the target surface in a range of the first polisher between a first circle concentric with the first polisher and a second circle having a larger diameter than that of the first circle and being concentric with the first polisher, a plurality of the holes are located at intervals in at least one of a radial direction and a circumferential direction of the first polisher to intersect with a circle being concentric with the first polisher and having an arbitrary diameter equal to or larger than the diameter of the first circle and equal to or smaller than the diameter of the second circle, and a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the through holes, respectively.
10. The member of claim 5, wherein the first polisher has a peripheral edge in a substantially circular shape and rubs the target surface in a range of the first polisher between a first circle concentric with the first polisher and a second circle having a larger diameter than that of the first circle and being concentric with the first polisher, a plurality of the holes are located at intervals in at least one of a radial direction and a circumferential direction of the first polisher to intersect with a circle being concentric with the first polisher and having an arbitrary diameter equal to or larger than the diameter of the first circle and equal to or smaller than the diameter of the second circle, and a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the through holes, respectively.
11. The member of claim 2, wherein a plurality of the holes are located in a uniform positioning state, and a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the holes, respectively.
12. The member of claim 3, wherein a plurality of the holes are located in a uniform positioning state, and a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the holes, respectively.
13. The member of claim 5, wherein a plurality of the holes are located in a uniform positioning state, and a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the holes, respectively.
14. The member of claim 1, wherein a plurality of the holes are located, a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the holes, respectively, and orientations of the third polishers with respect to the second polishers are different between nearest ones of the second polishers.
15. The member of claim 2, wherein a plurality of the holes are located, a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the holes, respectively, and orientations of the third polishers with respect to the second polishers are different between nearest ones of the second polishers.
16. The member of claim 3, wherein a plurality of the holes are located, a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the holes, respectively, and orientations of the third polishers with respect to the second polishers are different between nearest ones of the second polishers.
17. The member of claim 5, wherein a plurality of the holes are located, a plurality of the second polishers and a plurality of the third polishers are provided to correspond to the holes, respectively, and orientations of the third polishers with respect to the second polishers are different between nearest ones of the second polishers.
18. The member of claim 7, wherein orientations of the third polishers with respect to the second polishers are different between nearest ones of the second polishers.
19. The member of claim 11, wherein orientations of the third polishers with respect to the second polishers are different between nearest ones of the second polishers.
20. A semiconductor manufacturing method comprising: pressing a target surface against a surface of a polishing member comprising a first polisher capable of rubbing the target surface, a second polisher surrounded by the first polisher, the second polisher having a hole along an edge of the second polisher between the second polisher and the first polisher, and a third polisher connecting the first polisher and the second polisher, supplying a polishing solution to the surface of the polishing member and inside the hole, and rotating the polishing member to rub the target surface, and moving the second polisher relative to the hole to supply the polishing solution in the hole to the surface of the polishing member.
Description:
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of priority from the prior U.S. Provisional Patent Application No. 62/294,326 filed on Feb. 12, 2016, the entire contents of which are incorporated herein by reference.
FIELD
[0002] The embodiments of the present invention relate to a polishing member and a semiconductor manufacturing method.
BACKGROUND
[0003] In a semiconductor manufacturing process, CMP (Chemical Mechanical Polishing) for polishing a polishing target film on a semiconductor substrate is performed. In the CMP, the polishing target film on the semiconductor substrate is pressed against a polishing pad to which a polishing solution is supplied, and is polished.
[0004] To hold the polishing solution or to supply the held polishing solution to a surface of a polishing layer of the polishing pad, grooves or holes are formed on the polishing layer.
[0005] The polishing pad having grooves can diffuse the polishing solution uniformly on the surface of the polishing layer. However, the grooves cannot be formed only partway through the polishing layer in the depth direction to ensure a mechanical strength of the polishing layer. Due to such restriction in the depth of the grooves, the function of the grooves to diffuse the polishing solution is declined when the depth of the grooves is decreased with depletion of the polishing layer by dressing. Therefore, the polishing pad having grooves adversely has a short lifetime.
[0006] On the other hand, the holes can be formed to pass through the polishing layer. Therefore, the holes are not lost even when the polishing layer is depleted by dressing and thus the polishing pad having holes has a longer lifetime. However, the conventional holes have a shape, such as a circular shape, that is not easily collapsed by frictional force of the polishing and it is difficult to supply the polishing solution efficiently to the surface of the polishing layer.
[0007] Therefore, the conventional polishing pad has a problem that the polishing rate of a polishing target film is hard to increase.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a sectional view showing a polishing apparatus 1 according to a first embodiment;
[0009] FIG. 2A is a partial plan view showing a polishing pad according to the first embodiment, FIG. 2B is a sectional view along a line IIB-IIB in FIG. 2A, and FIG. 2C is an entire plan view showing the polishing pad;
[0010] FIG. 3 is an explanatory diagram of a dimension of the polishing pad according to the first embodiment;
[0011] FIG. 4A is an explanatory diagram of a distance between through holes of the polishing pad according to the first embodiment, and FIG. 4B is an explanatory diagram of a dimension of a polishing pad of a comparative example;
[0012] FIG. 5 is a flowchart showing a semiconductor manufacturing method according to the first embodiment;
[0013] FIG. 6A is a sectional view showing a film forming process of a second silicon oxide film in the semiconductor manufacturing method according to the first embodiment, and FIG. 6B is a sectional view showing the second silicon oxide film after being polished;
[0014] FIG. 7 is a plan view showing a displaced state of second polishers in a process of polishing the second silicon oxide film in the semiconductor manufacturing method according to the first embodiment;
[0015] FIG. 8 is a plan view showing a polishing pad according to a second embodiment; and
[0016] FIG. 9 is an explanatory diagram of a dimension of the polishing pad according to the second embodiment.
DETAILED DESCRIPTION
[0017] A polishing member according to an embodiment includes a first polisher, a second polisher, and a third polisher. The first polisher is capable of rubbing a target surface. The second polisher is surrounded by the first polisher. A hole along an edge of the second polisher is present between the first polisher and the second polisher. The third polisher connects the first polisher and the second polisher.
[0018] Embodiments will now be explained with reference to the accompanying drawings. The present invention is not limited to the embodiments.
First Embodiment
[0019] An embodiment of a polishing member having through holes in a horseshoe shape is explained first as a first embodiment.
[0020] FIG. 1 is a schematic sectional view showing a polishing apparatus 1 according to the first embodiment.
[0021] As shown in FIG. 1, the polishing apparatus 1 includes a polishing pad 2 being an example of a polishing member, a polishing table 3, a holder 4, a supplier 5, drive sources 71 and 72, and a controller 8.
[0022] The polishing pad 2 is formed in a plate shape being circular in a planar view. The polishing pad 2 polishes a surface (the lower surface in FIG. 1) of a polishing target film 61 on a semiconductor substrate 6, which is an example of a target surface, using an upper surface as a polishing surface 22a.
[0023] The polishing table 3 has a circular shape with a substantially same diameter as that of the polishing surface 22a in a planar view. The polishing pad 2 is fixed to an upper surface of the polishing table 3 by a fixing method such as adhesion. The polishing table 3 is capable of rotating in the direction of an arrow A1 around a center of the polishing surface 22a with drive force of the drive source 71 such as a motor. Due to rotation of the polishing table 3, the polishing pad 2 can rotate with the polishing table 3 in an integrated manner.
[0024] The holder 4 is, for example, a head (jig) that holds the semiconductor substrate 6. The holder 4 holds the entire semiconductor substrate 6. As shown in FIG. 1, the holder 4 holds a rear surface of the semiconductor substrate 6 and causes a front surface of the polishing target film 61 to face toward the polishing surface 22a. The holder 4 then presses and rubs the polishing target film 61 against the polishing surface 22a to which a polishing solution is supplied to polish the front surface of the polishing target film 61.
[0025] More specifically, the holder 4 polishes the polishing target film 61 while rotating in the direction of an arrow A2 with drive force of the drive source 72 such as a motor. The holder 4 pushes the semiconductor substrate 6 downward d1 using a pushing apparatus (not shown) to cause polishing pressure to act on the polishing pad 2.
[0026] The supplier 5 includes a nozzle 51, a pipe 52, and a supply source 53 of a polishing solution. The nozzle 51 is communicated with the supply source 53 of the polishing solution via the pipe 52. The polishing solution is a liquid to be used for polishing the polishing target film 61 and generally includes abrasive particles, that is, abrasive grains. The polishing solution is also called slurry. The nozzle 51 supplies a polishing solution L supplied from the supply source 53 to the polishing surface 22a.
[0027] The controller 8 controls operations of respective working portions of the polishing apparatus 1, such as the drive sources 71 and 72, the supplier 5, and the pushing apparatus of the holder 4.
[0028] To prevent the polishing pad 2 from being clogged with the polishing solution, the polishing apparatus 1 can include a dresser that slits the polishing pad 2.
[0029] FIG. 2A is a partial plan view showing the polishing pad 2 according to the first embodiment. FIG. 2B is a sectional view along a line IIB-IIB in FIG. 2A. FIG. 2C is an entire plan view showing the polishing pad 2.
[0030] As shown in FIG. 2B, the polishing pad 2 has a cushion layer 21 and a polishing layer 22.
[0031] The cushion layer 21 is formed of, for example, a porous sheet such as nonwoven fabric.
[0032] The polishing layer 22 is placed on the cushion layer 21. An upper surface of the polishing layer 22 is the polishing surface 22a.
[0033] The polishing layer 22 is formed of, for example, a porous resin material such as foamed polyurethane. Because being formed of a porous resin material, the polishing layer 22 can hold the abrasive particles of the polishing solution.
[0034] To hold the polishing solution and supply the held polishing solution to the polishing surface 22a, the polishing layer 22 has a plurality of through holes 23 passing through the polishing surface 22a and a rear surface 22b as shown in FIGS. 2A to 2C. The through holes 23 are positioned uniformly on the polishing layer 22. Specifically, the through holes 23 are positioned throughout the polishing layer 22. Sizes and shapes of the respective through holes 23 are the same. Shortest distances between nearest ones of the through holes 23 are the same. Due to uniform positioning of the through holes 23, the polishing solution in the through holes 23 easily reaches all areas of the polishing surface 22a.
[0035] The sizes and the number of the through holes 23 in the polishing pad 2 can be different from those in FIG. 2C.
[0036] The polishing layer 22 can have the same thickness as that of the cushion layer 21. For example, the thickness of the cushion layer 21 and the polishing layer 22 can be 1.3 millimeters.
(First to Third Polishers 24 to 26)
[0037] FIG. 3 is an explanatory diagram of a dimension of the polishing pad 2 according to the first embodiment.
[0038] As shown in FIGS. 2A and 3, the polishing layer 22 has a first polisher 24, second polishers 25, and third polishers 26.
[0039] As shown in FIG. 2C, the first polisher 24 has a peripheral edge in a circular shape being concentric with the polishing pad 2 and having a same diameter as that of the polishing pad 2. The first polisher 24 can face the polishing target film 61 and polish the polishing target film 61.
[0040] Specifically, the first polisher 24 polishes the polishing target film 61 by rotating together with the polishing table 3 in a state where the polishing target film 61 is pressed against the first polisher 24.
[0041] More specifically, the first polisher 24 polishes the polishing target film 61 in a partial range 241 of the first polisher 24 between a first circle C1 and a second circle C2 as shown in FIGS. 2C and 1. The first circle C1 is a circle being concentric with the first polisher 24 and having a smaller diameter than that of the first polisher 24. The second circle C2 is a circle being concentric with the first polisher 24 and having a diameter larger than that of the first circle C1 and smaller than that of the first polisher 24.
[0042] The second polishers 25 are surrounded by the first polisher 24. The through holes 23 are located along edges 251. (see FIG. 3) of the second polishers 25 between the first polisher 24 and the second polishers 25, respectively. That is, the second polishers 25 are surrounded by the first polisher 24 to sandwich the through holes 23 with the first polisher 24 except for positions of the third polishers 26, respectively.
[0043] As shown in FIGS. 2A and 3, the through holes 23 according to the first embodiment have a horseshoe shape, that is, a C-shape or a Landolt-ring shape in a planar view. Associated with the horseshoe shape of the through holes 23, the second polishers 25 according to the first embodiment have a substantially circular shape along the through holes 23 in a planar view.
[0044] When the polishing target film 61 is to be polished, the second polishers 25 are moved relative to the through holes 23 by friction force of the polishing acting between the second polishers 25 and the polishing target film 61. Due to the movement relative to the through holes 23, the second polishers 25 collapse the through holes 23 in the relative movement direction. Collapse of the through holes 23 causes the polishing solution held in the through holes 23 to be pushed out of the through holes 23 and be supplied to the polishing surface 22a.
[0045] The third polishers 26 connect the first polisher 24 and the second polishers 25. As shown in FIG. 2A, the third polishers 26 according to the first embodiment are each interposed between both ends 23a and 23b of the corresponding through hole 23. Similarly to the first polisher 24 and the second polishers 25, the third polishers 26 can polish the polishing target film 61.
[0046] As shown in FIG. 3, a width of the third polisher 26 in a direction orthogonal to a central line 261 thereof is smaller than a width in the same direction of the second polisher 25. More specifically, the width of the third polisher 26 gradually decreases from a side of the first polisher 24 to a side of the corresponding second polisher 25 and a smallest width W1 of the third polisher 26 is smaller than a largest width W2 of the second polisher 25.
[0047] Specific dimensions of the through hole 23 and the second polisher 25 are not particularly limited. For example, the smallest width W1 of the third polisher 26 can be 1.3 millimeters. The largest width W2 of the second polisher 25 can be 2.6 millimeters. A width W3 of the through hole 23 can be 0.4 millimeter. An outer diameter W4 of the through hole 23 can be 3.4 millimeters.
[0048] FIG. 4A is an explanatory diagram of a distance between the through holes 23 of the polishing pad 2 according to the first embodiment. FIG. 4B is an explanatory diagram of a dimension of a polishing pad of a comparative example. FIG. 4B shows circular through holes 230 having a same cross-sectional area as that of the through holes 23 according to the first embodiment. As shown in FIGS. 4A and 4B, a shortest distance D_23 between the through holes 23 in the first embodiment is shorter than a shortest distance D_230 of the through holes 230 in the comparative example.
[0049] Specific numerical values of the cross-sectional area of the through holes 23 and the distance D_23 are not particularly limited. For example, the cross-sectional area of the through holes 23 can be 3.14 mm.sup.2. The distance D_23 can be 2 millimeters.
[0050] Because the through holes 23 are locally positioned in the polishing pad of the comparative example, stiffness of the polishing layer around the through holes 23 is high. Therefore, the through holes 230 are not easily collapsed by frictional force of polishing. The polishing pad of the comparative example has a large distance D_230 between the through holes 230.
[0051] Because the through holes 230 are not easily collapsed and the distance D_230 is large, it is difficult to spread the polishing solution in the through holes 230 throughout the polishing surface in the polishing pad of the comparative example.
[0052] In contrast thereto, in the polishing pad 2 according to the first embodiment, the second polishers 25 are connected to the first polisher 24 with the third polishers 26 more constricted and more fragile than the second polishers 25. Accordingly, frictional force of polishing acting on the second polishers 25 is superior to stiffness of the third polishers 26. Therefore, the frictional force of polishing enables the third polishers 26 to be deflected to move the second polishers 25 relative to the through holes 23. Due to the relative movement of the second polishers 25, the through holes 23 can be easily collapsed.
[0053] Furthermore, in the polishing pad 2 according to the first embodiment, the through holes 23 are formed over a wide range to surround the second polishers 25, respectively. Therefore, the distance between adjacent ones of the through holes 23 can be shortened.
[0054] Because the through holes 23 can be easily collapsed and the distance between adjacent ones of the through holes 23 can be shortened, the polishing pad 2 according to the first embodiment can promptly spread the polishing solution in the through holes 23 throughout the polishing surface 22a. In this way, the polishing target film 61 can be polished with the polishing pad 2 promptly and uniformly.
[0055] Therefore, with the polishing pad 2 according to the first embodiment, the polishing rate of the polishing target film 61 can be increased (that is, the polishing time can be reduced). Furthermore, the uniformity in the film thickness (hereinafter, also "in-plane uniformity") of the polishing target film 61 within the plane of a wafer after the polishing can be enhanced.
[0056] As shown in FIG. 2C, the through holes 23 are positioned at intervals in at least one of a radial direction d2 and a circumferential direction d3 of the first polisher 24, respectively, to intersect with a circle C3 having an arbitrary diameter equal to or larger than the diameter of the first circle C1 and equal to or smaller than the diameter of the second circle C2 and being concentric with the first polisher 24. That is, the arbitrary circle C3 between the first circle C1 and the second circle C2 intersects with one or more through holes 23 among the through holes 23.
[0057] Due to the positioning of the through holes 23 intersecting with the arbitrary circle C3, the polishing solution in the through holes 23 can be supplied to the polishing surface 22a more promptly and more uniformly in the range 241 of the first polisher 24 to be used for polishing of the polishing target film 61. This can further enhance the polishing rate and the in-plane uniformity.
[0058] The through holes 23 can alternatively intersect with an arbitrary circle having a diameter equal to or smaller than that of the first polisher 24 and being concentric with the first polisher 24.
[0059] As shown in FIG. 2A, orientations of the third polishers 26 with respect to the second polishers 25 differ according to the second polishers 25.
[0060] More specifically, the orientations of the third polishers 26 with respect to the second polishers 25 are different at least between nearest ones of the second polishers 25. In the example shown in FIG. 2A, one second polisher 25 has six nearest second polishers 25 around the second polisher 25. Directions of the front, rear, right, and left are defined as shown by arrows in FIG. 2A. A third polisher 26 corresponding to one second polisher 25A in FIG. 2A is placed on the front side of the second polisher 25A. In contrast thereto, third polishers 26 corresponding to the six second polishers 25 nearest to the second polisher 25A are placed on the rear, left, and right sides of the second polishers 25.
[0061] More specifically, the second polishers 25 are nearest in a first direction d01, a second direction d02, and a third direction d03, which are different by 60 degrees, respectively. Alternate third polishers 26 along the first direction d01 corresponding to the second polishers 25 nearest in the first direction d01 are placed in same orientations. Alternate third polishers 26 along the second direction d02 corresponding to the second polishers 25 nearest in the second direction d02 are placed in opposite directions. Alternate third polishers 26 along the third direction d03 corresponding to the second polishers 25 nearest in the third direction d03 are placed in opposite directions.
[0062] Due to this placement of the third polishers 26, polishing friction against respective parts of the polishing target film 61 can be uniformed and thus the in-plane uniformity can be further enhanced. The orientations of the third polishers 26 with respect to the second polishers 25 are not limited to those shown in FIG. 2A. For example, the third polishers 26 can be placed on right front, left front, right rear, and left rear sides of the corresponding polishers 25, respectively.
(Semiconductor Manufacturing Method)
[0063] An embodiment of a semiconductor manufacturing method to which the polishing apparatus 1 shown in FIG. 1 is applied is explained next. FIG. 5 is a flowchart showing a semiconductor manufacturing method according to the first embodiment. FIG. 6A is a sectional view showing a film forming process of a second silicon oxide film 604 in the semiconductor manufacturing method according to the first embodiment. FIG. 6B is a sectional view showing the second silicon oxide film 604 after being polished.
[0064] In the first embodiment, a semiconductor device that includes an element isolation structure with the second silicon oxide film 604 is manufactured as shown in FIG. 6B.
[0065] Specifically, a first silicon oxide film 601 shown in FIGS. 6A and 6B is first formed on a silicon substrate 600 being an example of the semiconductor substrate 6 (Step S1 in FIG. 5). A film thickness of the first silicon oxide film 601 is not particularly limited and can be, for example, 10 nanometers.
[0066] Next, a silicon nitride film 602 shown in FIGS. 6A and 6B are formed on the first silicon oxide film 601 (Step S2 in FIG. 5). A film thickness of the silicon nitride film 602 is not particularly limited and can be, for example, 50 nanometers.
[0067] Subsequently, trenches 603 shown in FIGS. 6A and 6B are formed in a predetermined element isolation region in the silicon substrate 60 on which the first silicon oxide film 601 and the silicon nitride film 602 are stacked (Step S3 in FIG. 5). The trenches 603 can be formed, for example, by photolithography and dry etching. A depth of the trenches 603 is not particularly limited and can be, for example, 350 nanometers from the top surface of the silicon nitride film 602.
[0068] Next, as shown in FIG. 6A, the second silicon oxide film 604 is formed on the silicon nitride film 602 and the trenches 603 (Step S4 in FIG. 5). Accordingly, the second silicon oxide film 604 is embedded in the trenches 603 to be in contact with the silicon substrate 600, the first silicon oxide film 601, and the silicon nitride film 602. The second silicon oxide film 604 is formed also on the silicon nitride film 602.
[0069] Subsequently, the polishing apparatus 1 starts polishing the second silicon oxide film 604 (that is, the polishing target film 61) on the silicon nitride film 602 (Step S5 in FIG. 5).
[0070] Specifically, the nozzle 51 supplies a polishing solution including cerium oxide to the polishing surface 22a of the polishing pad 2 that is fixed on the polishing table 3. The holder 4 holding the silicon substrate 600 presses the second silicon oxide film 604 against the polishing surface 22a with polishing pressure applied by the pushing apparatus (not shown).
[0071] In a state where the second silicon oxide film 604 is pressed against the polishing surface 22a, the drive sources 71 and 72 rotate the polishing table 3 and the holder 4. The polishing pressure at that time is not particularly limited and can be, for example, 210 hPa. Also the rotational speed of the polishing table 3 is not particularly limited and can be, for example, 80 r/min.
[0072] FIG. 7 is a plan view showing a displaced state of the second polishers 25 in a process of polishing the second silicon oxide film 604 in the semiconductor manufacturing method according to the first embodiment.
[0073] A part of the polishing solution supplied from the nozzle 51 to the polishing surface 22a flows into the through holes 23 and is held in the through holes 23. When the second silicon oxide film 604 is polished, the second polishers 25 are moved relative to the through holes 23 by frictional force of the polishing. With the relative movement, the second polishers 25 partially collapse the through holes 23 surrounding the second polishers 25, respectively. Due to collapse of the through holes 23, the polishing solution held in the through holes 23 is pushed out of the through holes 23 and is supplied promptly and efficiently throughout the polishing surface 22a. This enables prompt and uniform polishing of the silicon oxide film 604.
[0074] Next, as shown in FIG. 5, the controller 8 determines whether the silicon nitride film 602 is exposed (Step S6). At that time, the controller 8 can determine that the silicon nitride film 602 is exposed by detecting a change in drive torque current of the polishing table 3 occurring at a time of exposure of the silicon nitride film 602.
[0075] When the silicon nitride film 602 is exposed (YES at Step S6), the polishing apparatus 1 finishes the polishing of the second silicon oxide film 604 (Step S7). In this way, a semiconductor device having the silicon nitride film 602 exposed is obtained as shown in FIG. 66. When the silicon nitride film 602 is not exposed (NO at Step S6), the controller 8 repeats the determination (Step S6).
[0076] As explained above, according to the semiconductor manufacturing method of the first embodiment, the polishing rate and the in-plane uniformity of the polishing target film 61 can be enhanced with use of the polishing pad 2 having the through holes 23 in a horseshoe shape. This can increase the manufacturing efficiency and the yield rate of the semiconductor device.
Second Embodiment
[0077] An embodiment of a polishing member having through holes in a spiral shape is explained next as a second embodiment. In the second embodiment, constituent parts corresponding to those of the first embodiment are denoted by like reference characters to simplify explanations.
[0078] FIG. 8 is a plan view showing the polishing pad 2 according to the second embodiment. FIG. 9 is an explanatory diagram of a dimension of the polishing pad 2 according to the second embodiment.
[0079] As shown in FIG. 8, the through holes 23 in the second embodiment have a spiral shape (that is, a helical shape) in a planar view. Because the through holes 23 have a spiral shape, the third polishers 26 have an arc shape in a planar view.
[0080] As shown in FIG. 9, the width W1 of the third polishers 26 is smaller than the largest width W2 of the second polishers 25. The width W1 of the third polishers 26 can be constant. For example, the width W1 of the third polishers 26 can be 0.4 millimeter and the largest width W2 of the second polishers 25 can be 1.5 millimeters. The width W3 of the through holes 23 can be 0.4 millimeter and the outer diameter W4 of the through holes 23 can be 3.3 millimeters.
[0081] In the second embodiment, similarly in the first embodiment, the second polishers 25 are connected to the first polisher 24 with the third polishers 26 more constricted than the second polishers 25. The through holes 23 are positioned over a wide range to surround the second polishers 25, respectively. Accordingly, the through holes 23 can be easily collapsed by movement of the second polishers 25 relative to the corresponding through holes 23 with frictional force of polishing. The distance between adjacent ones of the through holes 23 can be shortened compared to that in the through holes 230 (see FIG. 4B) of the comparative example.
[0082] Therefore, also in the polishing pad 2 according to the second embodiment, the polishing solution in the through holes 23 can be spread promptly throughout the polishing surface 22a. This can enhance the polishing rate and the in-plane uniformity also in the second embodiment.
[0083] Furthermore, also in the second embodiment, the through holes 23 are positioned at intervals in at least one of the radial direction d2 and the circumferential direction d3 to intersect with the arbitrary circle C3 as shown in FIG. 8. This can further enhance the polishing rate and the in-plane uniformity.
[0084] As shown in FIG. 8, the orientations of the third polishers 26 with respect to the second polishers 25 differ at least between nearest ones of the second polishers 25 also in the second embodiment. Similarly in FIG. 2A, a second polisher 25 having the corresponding third polisher 26 placed on the front side is denoted by reference character 25A in FIG. 8. Accordingly, the in-plane uniformity can be further enhanced.
[0085] When the polishing pad 2 according to the second embodiment is applied to manufacturing of the semiconductor device shown in FIG. 6B, the manufacturing efficiency and the yield rate can be increased similarly in the first embodiment.
[0086] As described above, according to the second embodiment, the polishing pad 2 has the through holes 23 in a spiral shape. Therefore, the polishing rate and the in-plane uniformity of the polishing target film 61 can be enhanced.
[0087] The shape of the through holes 23 is not limited to the horseshoe shape and the spiral shape as long as the shape enables formation of the second polishers 25 and the third polishers 26.
[0088] The present embodiments can be applied also to manufacture semiconductor devices other than that shown in FIG. 6B.
[0089] While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
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