阅读说明：本技术 用于解决碳化硅晶圆化学机械抛光后产生局部高点的方法、陶瓷盘、化学机械抛光装置 (Method for solving local high point generation after chemical mechanical polishing of silicon carbide wafer, ceramic disc and chemical mechanical polishing device ) 是由 刘少华 李坤宁 杨兴娇 李雪涛 赵焕君 崔景光 于 2021-08-26 设计创作，主要内容包括：本发明公开一种用于解决碳化硅晶圆化学机械抛光后产生局部高点的方法、一种陶瓷盘及应用其的化学机械抛光装置,涉及碳化硅晶圆加工技术领域,通过改变陶瓷盘贴片区域的形状来达到改变晶圆局部受力分布,从而研磨去除掉晶圆局部高点。本发明所述的用于解决碳化硅晶圆化学机械抛光后产生局部高点的方法,通过车床将陶瓷盘的贴片区域车成与晶圆形状一致的凹形曲面,且从圆形的贴片区域的边缘向中心逐渐下凹1～10um,以使设备的压力部件施加压力到陶瓷盘时,贴片区域的边缘区域压力比中心区域压力高。(The invention discloses a method for solving the problem that local high points are generated after chemical mechanical polishing of a silicon carbide wafer, a ceramic disc and a chemical mechanical polishing device applying the ceramic disc, and relates to the technical field of silicon carbide wafer processing. According to the method for solving the problem that the local high points are generated after the chemical mechanical polishing of the silicon carbide wafer, the chip mounting area of the ceramic disc is turned into the concave curved surface which is consistent with the shape of the wafer through the lathe, and the concave curved surface is gradually recessed from the edge of the circular chip mounting area to the center by 1-10 microns, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the chip mounting area is higher than that of the center area.)

1. A method for solving the problem that local high points are generated after chemical mechanical polishing of a silicon carbide wafer is characterized in that a surface mounting area of a ceramic disc is processed into a concave curved surface consistent with the shape of the wafer, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the surface mounting area is higher than that of the central area.

2. The method for solving the problem of local high points generated after the chemical mechanical polishing of the silicon carbide wafer is carried out according to claim 1, wherein the chip area of the ceramic disc is turned into a concave curved surface consistent with the shape of the wafer through a lathe, and the concave curved surface is gradually depressed from the edge of the circular chip area to the center by 1-10 um, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the chip area is higher than that of the center area.

3. A method for solving the problem of local high points generated after chemical mechanical polishing of a silicon carbide wafer is characterized in that a patch area of a ceramic disc is processed into a convex curved surface consistent with the shape of the wafer, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the patch area is lower than that of the central area.

4. The method for solving the problem of local high points generated after the chemical mechanical polishing of the silicon carbide wafer is carried out according to claim 3, wherein the chip area of the ceramic disc is lathed into a convex curved surface which is consistent with the shape of the wafer through a lathe, and the convex surface gradually protrudes from the edge to the center of the circular chip area by 1-10 um, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the chip area is lower than that of the center area.

5. A method for solving the problem that local high points are generated after chemical mechanical polishing of a silicon carbide wafer is characterized in that a patch area of a ceramic disc is processed into a concave-convex curved surface which is consistent with the shape of the wafer, and the convex curved surface corresponds to the position of the high point of the wafer, so that when a pressure part of equipment applies pressure to the ceramic disc, the pressure of the convex curved surface of the patch area is higher than that of the concave curved surface.

6. The method for solving the local high points generated after the chemical mechanical polishing of the silicon carbide wafer is carried out according to claim 5, wherein the pasting area of the ceramic disc is lathed into a rugged curved surface which is consistent with the shape of the wafer, the convex curved surface corresponds to the position of the high point of the wafer, and the height difference between the convex curved surface and the concave curved surface is not higher than 10 μm, so that when a pressure part of the equipment applies pressure to the ceramic disc, the pressure of the convex curved surface of the pasting area is higher than that of the concave curved surface.

7. A ceramic disk, comprising: the ceramic disc comprises a ceramic disc body, wherein the ceramic disc body is provided with a plurality of patch areas which are distributed at intervals and used for fixing wafers, the patch areas are concave curved surfaces which are consistent with the shapes of the wafers, and the concave curved surfaces are gradually concave from the edges of the circular patch areas to the center by 1-10 mu m;

or the patch area is a convex curved surface consistent with the shape of the wafer, and gradually protrudes upwards by 1-10 um from the edge of the circular patch area to the center.

8. A ceramic disk, comprising: the ceramic disc body, the ceramic disc body has a plurality of interval distribution's the paster region that is used for fixed wafer, the paster region is the unsmooth shape curved surface unanimous with the wafer shape, and convex surface corresponds the wafer high point position, and convex surface and concave surface's difference in height is not higher than 10 um.

9. A ceramic disc according to claim 7 or 8 wherein a plurality of the patch regions are equally spaced.

10. A chemical mechanical polishing apparatus, comprising: a carrier plate having a first rotational axis and provided with a polishing pad, and a plurality of ceramic plates according to any one of claims 7 to 9 uniformly distributed and each provided with a hold-down member having a second rotational axis.

Technical Field

The invention relates to the technical field of processing of silicon carbide wafers, in particular to a method for solving the problem that local high points are generated after the silicon carbide wafers are subjected to chemical mechanical polishing, a ceramic disc and a chemical mechanical polishing device using the ceramic disc.

Background

Compared with a silicon wafer, the silicon carbide wafer has the advantages of large forbidden bandwidth, high saturated migration speed of current carriers, high thermal conductivity, high critical breakdown field strength and the like; therefore, the silicon carbide material is an ideal material for preparing high-temperature electronic devices and high-frequency high-power devices.

The processing flow of the silicon carbide wafer is basically divided into the following four steps: crystal processing, multi-line cutting, wafer grinding and polishing, cleaning and packaging. The Mohs hardness of the silicon carbide single crystal is as high as over 9.2, which is only slightly lower than that of diamond, and the hardness is high and the brittleness is large, so that the silicon carbide wafer is very difficult to process. At present, the fine grinding and polishing of silicon carbide wafers are all processed by Chemical-Mechanical polishing (CMP), which is: the ceramic disc stuck with the wafer is pressed on the bearing disc stuck with the polishing pad by a pressing component of the equipment, polishing liquid is added on the polishing pad, the ceramic disc and the bearing disc respectively rotate, the chemical corrosion is carried out on the surface of the wafer through the polishing liquid to reduce the hardness of the corrosion layer, and then under the action of pressure and rotation motion, the friction cutting action is carried out between abrasive particles in the grinding liquid and the wafer, so that the corrosion layer is removed to achieve the purpose of grinding and polishing the wafer.

However, the center of the wafer and the edge of the wafer have inevitable processing temperature difference, so that the thickness of the edge of the wafer after the chemical mechanical polishing of the silicon carbide wafer is 1-5 um higher than that of the center of the wafer, and a high point or an annular high point at the edge of the wafer is formed, so that the flatness of the wafer is unqualified, and the qualified rate of finished products is reduced; meanwhile, the local unevenness of the wafer surface caused by the annular high points can cause the failure of an integrated circuit device manufactured by using the wafer as a substrate, and the utilization rate of the wafer and the qualification rate of the integrated circuit device are reduced.

In the prior art, the main solutions for generating local high points after chemical mechanical polishing of silicon carbide wafers are as follows: firstly, a pressing part of grinding equipment presents a concentric annular layout, so that the aim of independently controlling the pressure of circular rings with different radiuses is fulfilled, the technical equipment is complex to modify, an annular area for pressure control is not accurate enough, only the overall pressure distribution of a ceramic disc can be controlled, and the pressure distribution of a single chip and a chip can not be controlled; and secondly, the processed silicon carbide wafer is reworked after flatness detection and unqualified flatness, and is subjected to chemical mechanical polishing again, so that the qualification rate is low and the productivity utilization rate is low.

Therefore, how to provide a method for solving the local high point generated after the chemical mechanical polishing of the silicon carbide wafer, a ceramic disc and a chemical mechanical polishing device using the same become technical problems to be solved by those skilled in the art.

Disclosure of Invention

The invention aims to provide a method for solving the problem that local high points are generated after chemical mechanical polishing of a silicon carbide wafer, a ceramic disc and a chemical mechanical polishing device using the ceramic disc.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for solving the problem of local high points generated after chemical mechanical polishing of a silicon carbide wafer is characterized in that a surface mounting area of a ceramic disc is processed into a concave curved surface consistent with the shape of the wafer, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the surface mounting area is higher than that of the central area.

Specifically, the ceramic disc surface mounting area is turned into a concave curved surface consistent with the shape of the wafer through a lathe, and the concave curved surface gradually sinks from the edge of the circular surface mounting area to the center by 1-10 microns, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the surface mounting area is higher than that of the center area.

Compared with the prior art, the method for solving the problem of local high points generated after the chemical mechanical polishing of the silicon carbide wafer has the following advantages:

in the method for solving the problem of local high points generated after the chemical mechanical polishing of the silicon carbide wafer, the patch area corresponding to the wafer is concave at the center, so that the pressure of the edge area of the wafer is higher than that of the center area, the friction force of the edge of the wafer is large, the cutting effect of abrasive particles is large, and the problem of the high points of the edge of the wafer is well solved.

A method for solving the problem of local high points generated after chemical mechanical polishing of a silicon carbide wafer is characterized in that a chip mounting area of a ceramic disc is processed into a convex curved surface consistent with the shape of the wafer, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the chip mounting area is lower than that of the central area.

Specifically, the ceramic disc surface mounting area is turned into a convex curved surface consistent with the shape of the wafer through a lathe, and the convex surface gradually protrudes from the edge of the circular surface mounting area to the center by 1-10 microns, so that when a pressure component of the equipment applies pressure to the ceramic disc, the pressure of the edge area of the surface mounting area is lower than that of the center area.

Compared with the prior art, the method for solving the problem of local high points generated after the chemical mechanical polishing of the silicon carbide wafer has the following advantages:

in the method for solving the problem of local high points generated after the chemical mechanical polishing of the silicon carbide wafer, the patch area corresponding to the wafer is in a central convex shape, so that the pressure of the edge area of the wafer is lower than that of the central area, the central friction force of the wafer is large, the cutting effect of abrasive particles is large, and the problem of the high points of the wafer center is well solved.

A method for solving the problem of local high points generated after chemical mechanical polishing of a silicon carbide wafer is characterized in that a patch area of a ceramic disc is processed into a concave-convex curved surface which is consistent with the shape of the wafer, and the convex curved surface corresponds to the position of the high point of the wafer, so that when a pressure part of equipment applies pressure to the ceramic disc, the pressure of the convex curved surface of the patch area is higher than that of the concave curved surface.

Specifically, the ceramic disc is turned into a concave-convex curved surface which is consistent with the shape of the wafer through a lathe, the convex curved surface corresponds to the position of the wafer high point, and the height difference between the convex curved surface and the concave curved surface is not higher than 10um, so that when a pressure part of equipment applies pressure to the ceramic disc, the pressure of the convex curved surface of the ceramic disc is higher than that of the concave curved surface.

Compared with the prior art, the method for solving the problem of local high points generated after the chemical mechanical polishing of the silicon carbide wafer has the following advantages:

according to the method for solving the problem that local high points are generated after the chemical mechanical polishing of the silicon carbide wafer, the patch area corresponding to the wafer is uneven, and the convex curved surface corresponds to the high point position of the wafer, so that the high point position pressure of the wafer is higher than that of other areas, the friction force at the high point position of the wafer is large, the cutting effect of abrasive particles is large, and the problem of the high point of the wafer is well solved; and according to the actual processing condition of the wafer, the height position of the chip mounting area can be changed, so that the shape of the chip mounting area can be changed along with the position of the wafer height position.

A ceramic disk, comprising: the ceramic disc comprises a ceramic disc body, wherein the ceramic disc body is provided with a plurality of patch areas which are distributed at intervals and used for fixing wafers, the patch areas are concave curved surfaces which are consistent with the shapes of the wafers, and the concave curved surfaces are gradually concave from the edges of the circular patch areas to the center by 1-10 mu m;

or the patch area is a convex curved surface consistent with the shape of the wafer, and gradually protrudes upwards by 1-10 um from the edge of the circular patch area to the center.

A ceramic disk, comprising: the ceramic disc body, the ceramic disc body has a plurality of interval distribution's the paster region that is used for fixed wafer, the paster region is the unsmooth shape curved surface unanimous with the wafer shape, and convex surface corresponds the wafer high point position, and convex surface and concave surface's difference in height is not higher than 10 um.

Specifically, in the ceramic disk, a plurality of the patch regions are equally spaced.

A chemical mechanical polishing apparatus comprising: the polishing device comprises a bearing disc with a first rotating shaft, a polishing pad and a plurality of ceramic discs which are uniformly distributed, wherein the ceramic discs are provided with a pressing part with a second rotating shaft.

Compared with the prior art, the ceramic disc and the chemical mechanical polishing device using the same have the same advantages as the method for solving the problem of local high points generated after the chemical mechanical polishing of the silicon carbide wafer, and are not repeated herein.

Drawings

Fig. 1 is a first perspective structural view of a ceramic disk according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a second perspective view of a ceramic disk according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a chemical mechanical polishing apparatus according to an embodiment of the present invention.

Reference numerals:

1-a ceramic disc; 11-a ceramic disc body; 110-patch area; 2-a wafer; 3-carrying tray; 31-a first shaft; 4-a polishing pad; 5-a press-down part; 51-second axis of rotation.

Detailed Description

For the convenience of understanding, the method for solving the local high point generated after the chemical mechanical polishing of the silicon carbide wafer, the ceramic disc and the chemical mechanical polishing device using the same provided by the embodiments of the present invention are described in detail below with reference to the attached drawings.

The embodiment of the invention provides a method for solving the problem that local high points are generated after chemical mechanical polishing of a silicon carbide wafer, wherein a patch area of a ceramic disc is processed into a concave curved surface with the shape consistent with that of the wafer, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the patch area is higher than that of the central area;

specifically, the ceramic disc surface mounting area is turned into a concave curved surface consistent with the shape of the wafer through a lathe, and the concave curved surface gradually sinks from the edge of the circular surface mounting area to the center by 1-10 microns, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the surface mounting area is higher than that of the center area.

The embodiment of the invention provides a method for solving the problem that local high points are generated after chemical mechanical polishing of a silicon carbide wafer, wherein a patch area of a ceramic disc is processed into a convex curved surface with the shape consistent with that of the wafer, so that when a pressure component of equipment applies pressure to the ceramic disc, the pressure of the edge area of the patch area is lower than that of the central area;

specifically, the ceramic disc surface mounting area is turned into a convex curved surface consistent with the shape of the wafer through a lathe, and the convex surface gradually protrudes from the edge of the circular surface mounting area to the center by 1-10 microns, so that when a pressure component of the equipment applies pressure to the ceramic disc, the pressure of the edge area of the surface mounting area is lower than that of the center area.

The embodiment of the invention provides a method for solving the problem that local high points are generated after chemical mechanical polishing of a silicon carbide wafer, wherein a patch area of a ceramic disc is processed into a concave-convex curved surface which is consistent with the shape of the wafer, and the convex curved surface corresponds to the position of the high point of the wafer, so that when a pressure part of equipment applies pressure to the ceramic disc, the pressure of the convex curved surface of the patch area is higher than that of the concave curved surface;

specifically, the ceramic disc is turned into a concave-convex curved surface which is consistent with the shape of the wafer through a lathe, the convex curved surface corresponds to the position of the wafer high point, and the height difference between the convex curved surface and the concave curved surface is not higher than 10um, so that when a pressure part of equipment applies pressure to the ceramic disc, the pressure of the convex curved surface of the ceramic disc is higher than that of the concave curved surface.

An embodiment of the present invention further provides a ceramic disk, including: the ceramic disc comprises a ceramic disc body 11, wherein the ceramic disc body 11 is provided with a plurality of patch areas 110 which are distributed at intervals and used for fixing the wafer 2, the patch areas 110 are concave curved surfaces which are consistent with the shape of the wafer 2, and the concave curved surfaces are gradually concave from the edge of the circular patch area 110 to the center by 1-10 microns, as shown in fig. 1;

or the chip area 110 is a convex curved surface with the same shape as the wafer 2, and gradually protrudes upwards by 1-10 um from the edge of the circular chip area 110 to the center;

or the chip mounting area 110 is a rugged curved surface with a shape consistent with that of the wafer 2, the convex curved surface corresponds to the position of the high point of the wafer 2, and the height difference between the convex curved surface and the concave curved surface is not higher than 10 um.

Specifically, as shown in fig. 2, in the ceramic disk 1 described above, the plurality of patch regions 110 may preferably be equally spaced.

It should be added here that, because of the difficulty of the silicon carbide wafer growth process, the silicon carbide wafer size is currently generally two, 4 inches and 6 inches, and each ceramic disk may be provided with a 5-piece 4-inch wafer chip area or a 3-piece 6-inch wafer chip area.

An embodiment of the present invention further provides a chemical mechanical polishing apparatus, as shown in fig. 3, including: a carrier plate 3 having a first rotation axis 31, and the carrier plate 3 is provided with a polishing pad 4, and a plurality of ceramic plates 1 as described in any one of the above, which are uniformly distributed, and each ceramic plate 1 is provided with a pressing member 5 having a second rotation axis 51.

In summary, the method for solving the problem of local high spots generated after the chemical mechanical polishing of the silicon carbide wafer, the ceramic disc and the chemical mechanical polishing apparatus using the same provided by the embodiments of the present invention mainly have the following advantages:

the operation structure is simple, the realization is easy, and the cost is low;

secondly, the surface mount area of the ceramic disc can be made into a corresponding shape according to the high points at different positions of the processed wafer, so that the pointing direction of the problem is accurate and controllable;

thirdly, the shape of the patch area can be smoothly gradually changed from a high point to a low point without being limited by the mechanical size;

and fourthly, the thickness of the ceramic disc is 1-2 cm, the ceramic disc can be recycled, the ceramic disc can be flattened by a lathe according to the actual processing effect, then the ceramic disc is made into a new shape, and the same ceramic disc can be used for repeatedly grinding different curved surfaces for at least hundreds of times.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.