Retainer ring used in chemical mechanical polishing

Abstract

To provide a retainer ring used in chemical mechanical polishing, which prevents polishing slurry from accumulating in grooves, prevents polishing unevenness, and improves product yield. [Solution] The retainer ring includes an annular body 10 and a support member. The annular body has an upper surface 11, a lower surface 12, an inner annular surface 13, an outer annular surface 14, and a plurality of grooves 15, the upper surface and the lower surface being opposite each other, the inner annular surface and the outer annular surface being opposite each other, and the upper surface and the lower surface being connected between both ends of the inner annular surface and the outer annular surface, respectively, the grooves being provided on the lower surface, each groove having an inner opening 151 and an outer opening 152, the inner opening being located on the inner annular surface, the outer opening being located on the outer annular surface, a first included angle being formed between a line direction connecting the inner opening and the outer opening and a radial direction of the annular body, the first included angle being in the range of 5 to 15 degrees. The support member is provided on the upper surface.

Description

[Technical field]

[0001] The present invention relates to a semiconductor wafer retaining ring for use in chemical mechanical polishing. [Background technology]

[0002] In the semiconductor manufacturing process, Chemical-Mechanical Polishing (CMP), also known as Chemical-Mechanical Planarization (CMP), is an essential step in the process of polishing semiconductor elements by supplying a polishing slurry onto the polishing pad of a polishing device, with the aim of flattening or thinning the semiconductor wafer.

[0003] Chemical mechanical polishing is generally performed by a chemical mechanical polishing apparatus, during the process of chemical mechanical polishing, the polishing pad rotates at a predetermined rotation speed, the wafer is held in a retaining ring, the polished surface of the wafer faces the polishing pad, and the polishing slurry is supplied near the center of the polishing pad and then dispersed on the surface of the polishing pad by centrifugal force, so that the polished surface of the wafer can be rotated and polished against the surface of the polishing pad.

[0004] During the chemical mechanical polishing process, the wafer is restricted in the retaining ring, and the underside of the retaining ring is usually provided with a number of grooves so that the polishing slurry that flows into the retaining ring can smoothly flow out of the retaining ring after polishing the wafer. When the retaining ring contacts the polishing pad, these grooves form drainage channels on the contact surface, and thus the polishing slurry mixed with the wafer polishing debris flows out of these drainage channels during the rotation process, so that the polishing slurry in the retaining ring can always be kept clean. From this, it can be seen that if the grooves on the retaining ring are not properly designed, the smooth flow of the polishing slurry will be hindered, which will affect the discharge efficiency of the polishing slurry, causing problems such as polishing unevenness and undesirable product yield. Therefore, improvements were needed. Summary of the Invention [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a retainer ring for use in chemical mechanical polishing, comprising an annular body and a support member. The annular body has an upper surface, a lower surface, an inner annular surface, an outer annular surface, and a number of grooves, the upper surface and the lower surface being opposite each other, the inner annular surface and the outer annular surface being opposite each other, and the upper surface and the lower surface being connected between both ends of the inner annular surface and the outer annular surface, respectively, the grooves being provided on the lower surface, each groove having an inner opening and an outer opening, the inner opening being located on the inner annular surface, the outer opening being located on the outer annular surface, and a first included angle being formed between a line direction connecting the inner opening and the outer opening and a radial direction of the annular body, the first included angle being in the range of 5 to 15 degrees. The support member is provided on the upper surface.

[0006] As a result, when the retainer ring contacts the underside of the annular body with the polishing pad to polish it, the formation of the first included angle of the groove ensures that the line direction connecting the inner opening and outer opening of the groove is well suited to the centrifugal path of the polishing slurry, allowing the polishing slurry added to the polishing pad via the annular body to pass smoothly through the groove, preventing the polishing slurry from accumulating in the groove, eliminating uneven polishing, and improving product yield.

[0007] In the above aspect, the first included angle may be 10 degrees.

[0008] In the above aspect, the lower surface may have a first portion and a second portion that are connected to each other, the first portion being connected to the inner annular surface and the second portion being connected to the outer annular surface, and an included angle being formed between the second portion and the first portion.

[0009] In the above aspect, the first portion may be a plane parallel to the upper surface, and the second portion may be a plane inclined relative to the first portion.

[0010] In the above aspect, the second portion may have a first end and a second end, the first end being connected to the first portion, and the second end being closer to the upper surface than the first end.

[0011] In addition, in the above aspect, the annular body may be formed surrounding the axial direction and have a second included angle of 95 to 105 degrees between the axial direction and the extension direction of a line connecting the first end and the second end of the second portion.

[0012] In the above aspect, the annular body may further have an annular groove located on the upper surface, and the support member may be housed in the annular groove.

[0013] In the above aspect, the annular groove may have a groove mouth and a groove body, the groove mouth having a first width in a radial direction of the annular body, and the groove body having a second width, the first width being greater than the second width.

[0014] In the above aspect, the annular groove may further include a connecting portion that connects obliquely between the groove opening and the groove body.

[0015] In the above aspect, the annular body may be formed surrounding the axial direction and may have a third included angle of 10 to 20 degrees between the connecting portion and the axial direction. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing a state in which a retainer ring used in the chemical mechanical polishing of the present invention is used to hold and polish a wafer; [Diagram 2] 1 is a perspective view of a retainer ring used in chemical mechanical polishing according to an embodiment of the present invention; FIG. [Diagram 3] FIG. 3 is a partial enlarged view of the circled area 3 in FIG. 2. [Figure 4] 2 is a schematic diagram showing the bottom surface of a retaining ring used in chemical mechanical polishing according to an embodiment of the present invention; FIG. [Diagram 5]FIG. 5 is a partial enlarged view of the circled area 5 in FIG. 4. [Figure 6] 2 is a schematic diagram showing a top view of a retaining ring used in chemical mechanical polishing according to an embodiment of the present invention; FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. [Figure 8] FIG. 8 is a partial enlarged view of the circled area 8 in FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] 1 to 6, Fig. 2 is a three-dimensional external view of a retaining ring used in chemical mechanical polishing according to an embodiment of the present invention, Fig. 3 is a partial enlarged view of the circled portion 3 in Fig. 2, Fig. 4 is a schematic view showing the bottom surface of the retaining ring used in chemical mechanical polishing according to an embodiment of the present invention, Fig. 5 is a partial enlarged view of the circled portion 5 in Fig. 4, and Fig. 6 is a schematic view showing the top surface of the retaining ring used in chemical mechanical polishing according to an embodiment of the present invention. The retaining ring is suitable for holding a semiconductor element during chemical mechanical polishing, and the semiconductor element can be polished against a polishing pad P. In some embodiments, the semiconductor element is a wafer W.

[0018] The retainer ring used in chemical mechanical polishing includes an annular body 10 and a support member 20. The annular body 10 has an upper surface 11, a lower surface 12, an inner annular surface 13, an outer annular surface 14, and a plurality of grooves 15, the upper surface 11 and the lower surface 12 being opposite to each other, the inner annular surface 13 and the outer annular surface 14 being opposite to each other, and the upper surface 11 and the lower surface 12 are connected between both ends of the inner annular surface 13 and the outer annular surface 14, respectively, the grooves 15 are provided on the lower surface 12, each groove 15 has an inner opening 151 and an outer opening 152, the inner opening 151 is located on the inner annular surface 13, the outer opening 152 is located on the outer annular surface 14, a first included angle θ1 is formed between a line direction connecting the inner opening 151 and the outer opening 152 and a radial direction of the annular body 10, and the first included angle θ1 is in a range of 5 to 15 degrees. The support member 20 is provided on the upper surface 11 .

[0019] Referring to FIG. 1, when a retainer ring holds a wafer W and performs chemical mechanical polishing, the retainer ring is fixed to a polishing head H via an annular body 10, and the polishing head H rotates the retainer ring and the wafer W via the annular body 10 and presses them against a rotating polishing pad P for polishing.

[0020] As a result, when the retainer ring contacts the underside 12 of the annular body 10 with the polishing pad P to polish it, the formation of the first included angle θ1 of the groove 15 ensures that the line direction connecting the inner opening 151 and the outer opening 152 of the groove 15 is well suited to the centrifugal path of the polishing slurry, and the polishing slurry added to the polishing pad P via the annular body 10 can pass smoothly through the groove 15, preventing the polishing slurry from accumulating in the groove 15, preventing uneven polishing, and improving product yield.

[0021] 1 and 2, in some embodiments, the size and shape of the inner annular surface 13 of the ring-shaped body 10 correspond to the appearance of the wafer W to be polished, so that the wafer W to be polished can be surrounded by the inner annular surface 13 of the ring-shaped body 10 and positioned on the ring-shaped body 10, and can be driven by the ring-shaped body 10 for polishing. In some embodiments, the ring-shaped body 10 is a ring-shaped structure formed to correspond to the wafer W. Here, the ring-shaped body 10 is formed to surround the wafer W along the axial direction A, and the diameter direction of the ring-shaped body 10 is a radial direction R perpendicular to the axial direction A. The inner annular surface 13 of the ring-shaped body 10 is annular, and the outer annular surface 14 surrounds the inner annular surface 13 and is concentric with the inner annular surface 13.

[0022] 1 and 6, when the retainer ring holds and polishes a wafer W, an upper surface 11 of the annular body 10 of the retainer ring is adapted to be joined to a polishing head H so as to be driven by the polishing head H. In some embodiments, the upper surface 11 of the annular body 10 may be provided with a plurality of joining structures 111 for joining with the polishing head H. In some embodiments, the joining structures 111 for joining the annular body 10 and the polishing head H may be, but are not limited to, screw holes.

[0023] 1 to 5, in some embodiments, the first included angle θ1 between the line direction connecting the inner opening 151 and the outer opening 152 of the groove 15 of the ring body 10 and the radial direction R of the ring body 10 is 13 degrees, but the present invention is not limited thereto. In other embodiments, the first included angle θ1 between the line direction connecting the inner opening 151 and the outer opening 152 of the groove 15 of the ring body 10 and the radial direction R of the ring body 10 may be 5 degrees, 6 degrees, 8 degrees, 11 degrees, 14 degrees, or 15 degrees. The retainer ring is suitable for chemical mechanical polishing, so that during the polishing process, the annular body 10 of the retainer ring is not only driven to rotate by the polishing head H, but also the polishing head H is pressed against the polishing pad P during polishing, and the polishing pad P also rotates at the same time, so that the movement path of the polishing slurry between the polishing head H and the polishing pad P is affected by the polishing pad P and the polishing head H, so that the polishing slurry does not simply flow out along the centrifugal force direction of the annular body 10, but also needs to consider the acting force between the polishing pad P and the annular body 10 at the same time. In some embodiments, the line direction connecting the inner opening 151 and the outer opening 152 of the groove 15 of the annular body 10 is set to have a first included angle θ1 with the radial direction R, which can be more suitable for the flow path of the polishing slurry, so that the polishing slurry does not accumulate in the groove 15, and the problem of uneven polishing caused by local accumulation of the polishing slurry can be avoided, so that the polishing uniformity can be improved, and the product yield can be further improved.

[0024] In some embodiments, the toroid 10 is made of a wear-resistant and corrosion-resistant material, such as, but not limited to, Polyetherketoneketone (PEKK), Polyetheretherketone (PEEK), Polyphenylene sulfide (PPS), polyethylene terephthalate, or polybutylene terephthalate.

[0025] 1, 2, 7 and 8, FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 2, and FIG. 8 is an enlarged view of a portion 8 circled in FIG. 7. In some embodiments, the lower surface of the ring 10 has a first portion 121 and a second portion 122 connected to each other, the first portion 121 being connected to the inner ring surface 13, and the second portion 122 being connected to the outer ring surface 14, with an included angle between the second portion 122 and the first portion 121. (i.e., the first portion 121 and the second portion 122 are not on the same plane). In some embodiments, the first portion 121 is a plane parallel to the upper surface 11, and the second portion 122 is a plane inclined relative to the first portion 121. This makes the surface area of ​​the upper surface 11 of the ring 10 larger than the surface area of ​​the lower surface 12, improving the stability of the ring 10 joined to the polishing head H.

[0026] Referring to Figures 1, 2, 7 and 8, in some embodiments, the second portion 122 of the lower surface 12 of the annular body 10 has a first end 1221 and a second end 1222, where the first end 1221 is connected to the first portion 121 and the second end 1222 is closer to the upper surface 11 than the first end 1221. As a result, when the lower surface 12 of the annular body 10 is brought into contact with the polishing pad P for polishing, the first portion 121 of the lower surface 12 contacts the polishing pad P, and a gap is created between the first portion 121 and the polishing pad P and the second portion 122. In this embodiment, the second end 1222 of the second portion 122 is farther away from the polishing pad P than the first end 1221, so that as the polishing slurry flows out from the inner annular surface 13 to the outer annular surface 14 of the annular body 10, the space for the polishing slurry to flow out gradually increases, reducing the resistance of the polishing slurry to flow from the inner annular surface 13 to the outer annular surface 14, and improving the flow of the polishing slurry through the grooves 15 of the annular body 10.

[0027] 1, 2, 7 and 8, in some embodiments, the second included angle θ2 is between the extension direction of the line connecting the first end 1221 and the second end 1222 of the second portion 122 of the lower surface 12 of the ring-shaped body 10 and the axial direction A. In some embodiments, the second included angle θ2 is in the range of 95 to 105 degrees. In some embodiments, the second included angle θ2 may be, but is not limited to, 95 degrees, 97 degrees, 98 degrees, 100 degrees, 101 degrees, 103 degrees, 104 degrees or 105 degrees. This prevents the included angle of the lower surface 12 of the ring-shaped body 10 from becoming too sharp while maintaining smooth discharge of the polishing slurry, thereby avoiding unnecessary damage to the wafer W by the retainer ring.

[0028] 7 and 8, in some embodiments, the annular body 10 further includes an annular groove 16 located on the upper surface 11. In some embodiments, the annular groove 16 is recessed from the upper surface 11, and the support member 20 is received within the annular groove 16 and protrudes from the upper surface 11.

[0029] The support member 20 is made of a material stronger than the ring body 10. In some embodiments, the support member 20 may be made of a metal material such as, but not limited to, stainless steel or an aluminum alloy. In this way, the support member 20 having a stronger strength is provided on the upper surface 11 of the ring body 10, thereby supporting the ring body 10 and preventing deformation of the ring body 10. In some embodiments, the position of the annular groove 16 in the radial direction R is between the inner annular surface 13 and the outer annular surface 14 to support the ring body 10 in a balanced manner.

[0030] 7 and 8, in some embodiments in which the annular body 10 has the annular groove 16, the annular groove 16 has a groove mouth 161, a connecting portion 162, and a groove body 163, which are connected in order, the groove mouth 161 opens to the upper surface 11, the groove body 163 is closer to the lower surface 12 than the groove mouth 161, and the connecting portion 162 connects obliquely between the groove mouth 161 and the groove body 163. In some embodiments, the shape and size of the groove body 163 approximately correspond to the shape and size of the support member 20, and the support member 20 can be accommodated in the groove body 163 from the groove mouth 161.

[0031] 7 and 8, in some embodiments, the groove mouth 161 has a first width W1 in the radial direction R, and the groove body 163 has a second width W2 in the radial direction R, and the first width W1 is greater than the second width W2. This reduces the resistance when assembling the support member 20 into the annular groove 16, and improves the convenience of assembling the support member 20. Here, the connecting portion 162 that is diagonally connected between the groove mouth 161 and the groove body 163 can guide the support member 20 to gradually enter the groove body 163 of the annular groove 16, thereby reducing the difficulty of assembling the support member 20 and improving the efficiency of assembling. In some embodiments, the depth of the connecting portion 162 along a direction perpendicular to the groove mouth 161 is smaller than the depth of the groove body 163 along a direction perpendicular to the groove mouth 161, and the ratio of the depths of the connecting portion 162 and the groove body 163 is in the range of 1:3 to 1:10. In some embodiments, when support member 20 is disposed within annular groove 16 , 70% or more of the area of ​​the annular face of support member 20 is surrounded by annular groove 16 .

[0032] 7 and 8, in some embodiments where the annular body 10 has an annular groove 16, the link portion 162 is formed circumferentially along the axial direction A and has a third included angle θ3 between the link portion 162 and the axial direction A of 10 to 20 degrees. In some embodiments, the third included angle θ3 between the link portion 162 and the axial direction A may be, but is not limited to, 10 degrees, 11 degrees, 13 degrees, 15 degrees, 18 degrees, or 20 degrees. [Explanation of symbols]

[0033] 10 Cyclic bodies 11 Top side 111 Joint structure 12 Bottom side 121 Part 1 122 Part 2 1221 1st end 1222 2nd end 13 Inner ring surface 14 Outer ring surface 15 groove 151 Inner opening 152 Outer opening 16 Annular groove 161 Mizonokuchi 162 Joint 163 Groove body 20 Support member A axis direction H Polishing Head R Radial direction P Polishing Pad W wafer W1 First width W2 Second width θ1 1st included angle θ2 2nd included angle θ3 3rd included angle

Claims

1. an annular body having an upper surface, a lower surface, an inner annular surface, an outer annular surface, and a plurality of grooves, the upper surface and the lower surface being opposite each other, the inner annular surface and the outer annular surface being opposite each other, and the upper surface and the lower surface being connected between both ends of the inner annular surface and the outer annular surface, respectively, the plurality of grooves being provided on the lower surface, each having an inner opening and an outer opening, the inner opening being located on the inner annular surface, the outer opening being located on the outer annular surface, and a first included angle of 5 to 15 degrees between a line direction connecting the inner opening and the outer opening and a radial direction of the annular body; A support member provided on the upper surface; 1. A retainer ring for use in chemical mechanical polishing comprising:

2. The retainer ring for use in chemical mechanical polishing of claim 1 , wherein the first included angle is 10 degrees.

3. 2. The retainer ring for use in chemical mechanical polishing of claim 1, wherein the lower surface has a first portion and a second portion joined together, the first portion being joined to the inner annular surface and the second portion being joined to the outer annular surface, the second portion having an included angle between the first portion.

4. 4. The retainer ring for use in chemical mechanical polishing according to claim 3, wherein the first portion is a plane parallel to the upper surface, and the second portion is a plane inclined relative to the first portion.

5. 5. The retainer ring for use in chemical mechanical polishing of claim 4, wherein the second portion has a first end and a second end, the first end being connected to the first portion and the second end being closer to the top surface than the first end.

6. 6. The retainer ring for use in chemical mechanical polishing as described in claim 5, wherein the annular body is formed surroundingly along the axial direction and has a second included angle of 95 to 105 degrees between the extension direction of a line connecting the first end and the second end of the second portion and the axial direction.

7. The retainer ring for use in chemical mechanical polishing of claim 1 , wherein the annular body further comprises an annular groove located in the upper surface, the support member being received in the annular groove.

8. 8. The retainer ring for use in chemical mechanical polishing of claim 7, wherein the annular groove has a groove mouth and a groove body, the groove mouth having a first width in a radial direction of the annular body and the groove body having a second width, the first width being greater than the second width.

9. 9. The retainer ring for use in chemical mechanical polishing according to claim 8, wherein the annular groove further includes a connecting portion that is obliquely connected between the groove mouth and the groove body.

10. 10. The retainer ring for use in chemical mechanical polishing according to claim 9, wherein the annular body is formed to surround the retainer ring along the axial direction and has a third included angle of 10 to 20 degrees between the connecting portion and the axial direction.

Images