阅读说明：本技术 一种双面研磨装置及方法 (Double-side grinding device and method ) 是由 赵晟佑 于 2019-10-22 设计创作，主要内容包括：本发明提供一种双面研磨装置及方法,涉及半导体晶圆领域。该装置包括：相对设置的第一定盘结构和第二定盘结构；其中,第一定盘结构包括相对设置的第一定盘和第二定盘,第二定盘背向第一定盘的表面贴附有第一研磨垫；第二定盘结构包括相对设置的第三定盘和第四定盘,第三定盘背向第四定盘的表面贴附有第二研磨垫,第一研磨垫和第二研磨垫相对设置,在第一研磨垫和第二研磨垫之间形成用于容纳待研磨基材的研磨区域；第二定盘和第三定盘的材质为热膨胀系数小于阈值的陶瓷材料。本发明实施例有效解决了对晶圆进行双面研磨的过程中,由于研磨温度升高导致定盘变形,从而影响晶圆平坦度的问题。(The invention provides a double-side grinding device and a double-side grinding method, and relates to the field of semiconductor wafers. The device includes: the first fixed disc structure and the second fixed disc structure are oppositely arranged; the first fixed disc structure comprises a first fixed disc and a second fixed disc which are oppositely arranged, and a first grinding pad is attached to the surface, back to the first fixed disc, of the second fixed disc; the second fixed disc structure comprises a third fixed disc and a fourth fixed disc which are oppositely arranged, a second grinding pad is attached to the surface of the third fixed disc, which is back to the fourth fixed disc, the first grinding pad and the second grinding pad are oppositely arranged, and a grinding area for accommodating a base material to be ground is formed between the first grinding pad and the second grinding pad; the second fixed disc and the third fixed disc are made of ceramic materials with thermal expansion coefficients smaller than a threshold value. The embodiment of the invention effectively solves the problem that the flatness of the wafer is influenced because the fixed disc is deformed due to the rise of the grinding temperature in the process of grinding the double surfaces of the wafer.)

1. A double-side polishing apparatus, comprising: the first fixed disc structure and the second fixed disc structure are oppositely arranged; wherein the content of the first and second substances,

the first fixed disc structure comprises a first fixed disc and a second fixed disc which are oppositely arranged, and a first grinding pad is attached to the surface, facing away from the first fixed disc, of the second fixed disc;

the second fixed disc structure comprises a third fixed disc and a fourth fixed disc which are oppositely arranged, a second grinding pad is attached to the surface, back to the fourth fixed disc, of the third fixed disc, the first grinding pad and the second grinding pad are oppositely arranged, and a grinding area used for accommodating a base material to be ground is formed between the first grinding pad and the second grinding pad;

the second fixed disc and the third fixed disc are made of ceramic materials with thermal expansion coefficients smaller than a threshold value.

2. The double-sided polishing apparatus as set forth in claim 1, wherein the surface of the first fixed plate facing the second fixed plate is provided with a first concave-convex structure, the surface of the second fixed plate facing the first fixed plate is provided with a second concave-convex structure, a convex portion of the first concave-convex structure extends into a concave portion of the second concave-convex structure and is abutted against a bottom of the concave portion of the second concave-convex structure, and a convex portion of the second concave-convex structure extends into a concave portion of the first concave-convex structure and is abutted against a bottom of the concave portion of the first concave-convex structure;

the third price fixing orientation the surface of fourth price fixing is provided with third concave-convex structure, the fourth price fixing orientation the surface of third price fixing is provided with fourth concave-convex structure, the bulge of third concave-convex structure stretches into the sunk part of fourth concave-convex structure, with the sunk part bottom laminating of fourth concave-convex structure, the bulge of fourth concave-convex structure stretches into the sunk part of third concave-convex structure, with the sunk part bottom laminating of third concave-convex structure.

3. The double-sided lapping apparatus of claim 2, further comprising:

a plurality of first cooling channels located between the first fixed plate and the second fixed plate, each first cooling channel extending along a radius direction of the first fixed plate structure, each first cooling channel being communicated with a first liquid inlet located in a central region of the first fixed plate structure, at least one first cooling channel of the plurality of first cooling channels having a first liquid outlet;

at least one annular second cooling channel is formed between the side wall of the convex part of the first concave-convex structure and the side wall of the concave part of the second concave-convex structure, wherein the convex part extends into the side wall of the concave part of the second concave-convex structure, and the second cooling channel is communicated with the plurality of first cooling channels;

a plurality of third cooling channels located between the third fixed plate and the fourth fixed plate, each third cooling channel extending along a radius direction of the second fixed plate structure, each third cooling channel being communicated with a second liquid inlet located in a central region of the second fixed plate structure, at least one third cooling channel of the plurality of third cooling channels having a second liquid outlet;

at least one annular fourth cooling channel is formed between the side wall of the convex part of the third concave-convex structure and the side wall of the concave part of the fourth concave-convex structure, wherein the convex part extends into the side wall of the concave part of the fourth concave-convex structure, and the fourth cooling channel is communicated with the plurality of third cooling channels.

4. The double-sided lapping apparatus of claim 3, further comprising:

and the cooling liquid conveying structure is communicated with the first liquid inlet, the second liquid inlet, the first liquid outlet and the second liquid outlet respectively, and is used for injecting cooling liquid into the first liquid inlet and the second liquid inlet and recovering the cooling liquid from the first liquid outlet and the second liquid outlet.

5. The double-sided lapping apparatus of claim 1, further comprising:

a sun gear arranged at the central part of the grinding area;

the ring gear is arranged at the peripheral part of the grinding area;

the carrier is arranged in the grinding area, a bearing hole for supporting the base material to be ground is formed in the carrier, peripheral teeth are arranged on the edge of the carrier, and the peripheral teeth are meshed with the tooth parts of the sun gear and the tooth parts of the ring gear respectively;

the first fixed disc structure and the second fixed disc structure rotate to drive the sun gear, the ring gear and the carrier to rotate.

6. A double-side polishing apparatus as claimed in claim 1, wherein the second fixed plate and the third fixed plate are made of silicon carbide ceramic having a thermal expansion coefficient of 3.7 x 10^-6/℃。

7. A double side grinder as claimed in claim 1, wherein the first and fourth fixed plates are made of stainless steel.

8. The double-sided lapping apparatus of claim 1, further comprising:

and the driving structure is connected with the first fixed disc and the fourth fixed disc and is used for controlling the first fixed disc structure and the second fixed disc structure to rotate.

9. A double-side lapping method applied to the double-side lapping apparatus of any one of claims 1 to 8, wherein when the double-side lapping apparatus comprises a sun gear, a ring gear and a carrier, the double-side lapping method comprises:

the first fixed disc structure and the second fixed disc structure rotate to drive the sun gear and the ring gear to rotate, and the sun gear and the ring gear drive the carrier to rotate relative to the first fixed disc structure and the second fixed disc structure through peripheral teeth on the edge of the carrier;

and the first grinding pad in the first fixed disc structure and the second grinding pad in the second fixed disc structure grind the surface of the base material to be ground arranged on the carrier.

10. The double-side grinding method according to claim 9, wherein when the double-side grinding apparatus further includes a first cooling passage, a second cooling passage, a third cooling passage, and a fourth cooling passage, the double-side grinding method further includes:

during grinding, cooling liquid is injected from a first liquid inlet in the central area of the first fixed disc structure, and flows out of a first liquid outlet through the first cooling channel and the second cooling channel;

and simultaneously, cooling liquid is injected from a second liquid inlet positioned in the central area of the second fixed disc structure, and flows out of a second liquid outlet through the third cooling channel and the fourth cooling channel.

Technical Field

The invention relates to the field of semiconductor wafers, in particular to a double-side grinding device and a double-side grinding method.

Background

Wafers are basic materials for manufacturing semiconductor chips, and the quality of the wafers has a great influence on the quality of the semiconductor chips, so that the processing of the wafers is an important link in the manufacturing process of the semiconductor chips. The double-side grinding technology mainly grinds the surface of the wafer through a physical reaction generated by relative rotation between the upper fixed plate and the lower fixed plate and the wafer and a chemical reaction generated by colloid grinding slurry and the wafer. In the prior art, due to the chemical reaction between the wafer and the polishing slurry and the friction between the wafer and the polishing pad on the fixed plate, the temperature rises during the polishing process, the fixed plate is deformed, the flatness of the wafer is reduced, and the quality of the wafer and the semiconductor chip is affected.

Disclosure of Invention

In view of the above, the present invention provides a double-side polishing apparatus and a double-side polishing method, which are used to solve the problem that the flatness of a wafer is affected due to deformation of a fixed plate caused by a polishing temperature increase during double-side polishing of the wafer.

In order to solve the above technical problem, the present invention provides a double-side polishing apparatus, including: the first fixed disc structure and the second fixed disc structure are oppositely arranged; wherein the content of the first and second substances,

the first fixed disc structure comprises a first fixed disc and a second fixed disc which are oppositely arranged, and a first grinding pad is attached to the surface, facing away from the first fixed disc, of the second fixed disc;

the second fixed disc structure comprises a third fixed disc and a fourth fixed disc which are oppositely arranged, a second grinding pad is attached to the surface, back to the fourth fixed disc, of the third fixed disc, the first grinding pad and the second grinding pad are oppositely arranged, and a grinding area used for accommodating a base material to be ground is formed between the first grinding pad and the second grinding pad;

the second fixed disc and the third fixed disc are made of ceramic materials with thermal expansion coefficients smaller than a threshold value.

Optionally, a first concave-convex structure is arranged on the surface of the first fixed disc facing the second fixed disc, a second concave-convex structure is arranged on the surface of the second fixed disc facing the first fixed disc, a convex portion of the first concave-convex structure extends into a concave portion of the second concave-convex structure and is attached to the bottom of the concave portion of the second concave-convex structure, and a convex portion of the second concave-convex structure extends into the concave portion of the first concave-convex structure and is attached to the bottom of the concave portion of the first concave-convex structure;

the third price fixing orientation the surface of fourth price fixing is provided with third concave-convex structure, the fourth price fixing orientation the surface of third price fixing is provided with fourth concave-convex structure, the bulge of third concave-convex structure stretches into the sunk part of fourth concave-convex structure, with the sunk part bottom laminating of fourth concave-convex structure, the bulge of fourth concave-convex structure stretches into the sunk part of third concave-convex structure, with the sunk part bottom laminating of third concave-convex structure.

Optionally, the double-side polishing apparatus further includes:

a plurality of first cooling channels located between the first fixed plate and the second fixed plate, each first cooling channel extending along a radius direction of the first fixed plate structure, each first cooling channel being communicated with a first liquid inlet located in a central region of the first fixed plate structure, at least one first cooling channel of the plurality of first cooling channels having a first liquid outlet;

at least one annular second cooling channel is formed between the side wall of the convex part of the first concave-convex structure and the side wall of the concave part of the second concave-convex structure, wherein the convex part extends into the side wall of the concave part of the second concave-convex structure, and the second cooling channel is communicated with the plurality of first cooling channels;

a plurality of third cooling channels located between the third fixed plate and the fourth fixed plate, each third cooling channel extending along a radius direction of the second fixed plate structure, each third cooling channel being communicated with a second liquid inlet located in a central region of the second fixed plate structure, at least one third cooling channel of the plurality of third cooling channels having a second liquid outlet;

at least one annular fourth cooling channel is formed between the side wall of the convex part of the third concave-convex structure and the side wall of the concave part of the fourth concave-convex structure, wherein the convex part extends into the side wall of the concave part of the fourth concave-convex structure, and the fourth cooling channel is communicated with the plurality of third cooling channels.

Optionally, the double-side polishing apparatus further includes:

and the cooling liquid conveying structure is communicated with the first liquid inlet, the second liquid inlet, the first liquid outlet and the second liquid outlet respectively, and is used for injecting cooling liquid into the first liquid inlet and the second liquid inlet and recovering the cooling liquid from the first liquid outlet and the second liquid outlet.

Optionally, the double-side polishing apparatus further includes:

a sun gear arranged at the central part of the grinding area;

the ring gear is arranged at the peripheral part of the grinding area;

the carrier is arranged in the grinding area, a bearing hole for supporting the base material to be ground is formed in the carrier, peripheral teeth are arranged on the edge of the carrier, and the peripheral teeth are meshed with the tooth parts of the sun gear and the tooth parts of the ring gear respectively;

the first fixed disc structure and the second fixed disc structure rotate to drive the sun gear, the ring gear and the carrier to rotate.

Optionally, the second fixed plate and the third fixed plate are made of silicon carbide ceramic, and the coefficient of thermal expansion of the silicon carbide ceramic is 3.7 × 10^-6/℃。

Optionally, the first fixed plate and the fourth fixed plate are made of stainless steel.

Optionally, the double-side polishing apparatus further includes:

and the driving structure is connected with the first fixed disc and the fourth fixed disc and is used for controlling the first fixed disc structure and the second fixed disc structure to rotate.

In addition, an embodiment of the present invention also provides a double-side polishing method applied to the double-side polishing apparatus described in any one of the above embodiments, when the double-side polishing apparatus includes a sun gear, a ring gear, and a carrier, the double-side polishing method including:

the first fixed disc structure and the second fixed disc structure rotate to drive the sun gear and the ring gear to rotate, and the sun gear and the ring gear drive the carrier to rotate relative to the first fixed disc structure and the second fixed disc structure through peripheral teeth on the edge of the carrier;

and the first grinding pad in the first fixed disc structure and the second grinding pad in the second fixed disc structure grind the surface of the base material to be ground arranged on the carrier.

Optionally, when the double-side polishing apparatus further includes a first cooling channel, a second cooling channel, a third cooling channel, and a fourth cooling channel, the double-side polishing method further includes:

during grinding, cooling liquid is injected from a first liquid inlet in the central area of the first fixed disc structure, and flows out of a first liquid outlet through the first cooling channel and the second cooling channel;

and simultaneously, cooling liquid is injected from a second liquid inlet positioned in the central area of the second fixed disc structure, and flows out of a second liquid outlet through the third cooling channel and the fourth cooling channel.

The technical scheme of the invention has the following beneficial effects: the fixed disc structure in the double-side grinding device is composed of at least two fixed discs, wherein the fixed disc close to the grinding area is made of ceramic materials with low thermal expansion coefficients, the fixed disc is prevented from deforming due to overhigh temperature in the grinding process, and the flatness of the ground wafer is effectively guaranteed.

Drawings

FIG. 1 is a schematic structural diagram of a fixed plate with convex deformation in the prior art;

FIG. 2 is a schematic structural diagram of a fixed plate with concave deformation in the prior art;

FIG. 3 is a schematic cross-sectional view of a double-side polishing structure according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a surface of the second fixed plate facing the first fixed plate according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a surface of a first fixed plate facing a second fixed plate according to an embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view of a first fixed plate structure according to an embodiment of the present invention;

FIG. 7 is a schematic cross-sectional view of a second fixed plate structure according to an embodiment of the present invention;

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.

During double-side polishing of a wafer, the polishing temperature is increased due to chemical reaction between the wafer and the polishing slurry and friction with the polishing pad. In order to stabilize the polishing temperature, it is necessary to suspend polishing and spray cold water to the polishing pad to cool the surface plate, which prolongs the production time and reduces the production efficiency. If the polishing is continued without performing the cooling treatment, the high temperature causes the surface plate to be deformed, and as shown in fig. 1, the upper surface plate 101 and the lower surface plate 102 both have a convex shape, or as shown in fig. 2, the upper surface plate 201 and the lower surface plate 202 both have a concave shape, so that the flatness of the processed wafer is lowered, and the quality of the semiconductor chip is deteriorated.

To solve the above problems, an embodiment of the present invention provides a double-side polishing apparatus, please refer to fig. 3, fig. 3 is a schematic structural diagram of the double-side polishing apparatus in an embodiment of the present invention, the apparatus includes: a first fixed disk structure 301 and a second fixed disk structure 302 which are oppositely arranged; wherein the content of the first and second substances,

the first fixed disk structure 301 comprises a first fixed disk 3011 and a second fixed disk 3012 which are oppositely arranged, and a first grinding pad 303 is attached to the surface of the second fixed disk 3012, which faces away from the first fixed disk 3011;

the second fixed disk structure 302 comprises a third fixed disk 3021 and a fourth fixed disk 3022 which are oppositely arranged, a second polishing pad 304 is attached to the surface of the third fixed disk 3021, which faces away from the fourth fixed disk 3022, the first polishing pad 303 and the second polishing pad 304 are oppositely arranged, and a polishing area for accommodating a substrate to be polished is formed between the first polishing pad 303 and the second polishing pad 304;

the second fixed disc 3012 and the third fixed disc 3021 are made of a ceramic material having a thermal expansion coefficient smaller than a threshold value;

specifically, in the related art, the fixed disks are generally made of stainless steel materials, but the fixed disks made of the stainless steel materials are easy to deform during the grinding process, in the double-side grinding device provided in the embodiment of the present invention, the second fixed disk 3012 and the third fixed disk 3021 are made of ceramic materials with thermal expansion coefficients smaller than a threshold value, where the threshold value is smaller than or equal to the thermal expansion coefficient of the stainless steel materials;

as can be seen from the specific structure of the double-side polishing apparatus provided in the embodiment of the present invention, in the double-side polishing apparatus provided in the embodiment of the present invention, the second fixed plate 3012 and the third fixed plate 3021 close to the polishing region are both made of a ceramic material having a thermal expansion coefficient smaller than a threshold value, and the ceramic material has a low thermal expansion coefficient, so that the second fixed plate 3012 and the third fixed plate 3021 are not easily affected by a high polishing temperature during the polishing process, and thus the stable structural configuration of the second fixed plate 3012 and the third fixed plate 3021 during the polishing process is ensured, and therefore, when the double-side polishing apparatus provided in the embodiment of the present invention is used to polish a wafer, deformation of the fixed plate due to the high temperature during the polishing process is improved, and thus the flatness of the polished wafer is effectively improved;

in addition, in the related art, in order to avoid the change of the shape of the fixed plate due to the high temperature caused by the polishing process, it is necessary to spray cold deionized water on the polishing pad and to provide a time for stabilizing the fixed plate, but this process may reduce the mass production time and lower the polishing efficiency. In the double-side grinding device provided by the embodiment of the invention, because the fixed disc can be prevented from being deformed due to the influence of high temperature in the grinding process, when the double-side grinding device provided by the embodiment of the invention is used for grinding a wafer, cold deionized water does not need to be sprayed on a grinding pad, and the time for stabilizing the fixed disc is given, so that the grinding process can be continuously carried out, and the grinding efficiency is improved;

in addition, when the fixed plate is deformed, a Dressing regulator (Dressing conditioner) is generally used to polish the polishing pad attached to the fixed plate, so that the surface of the polishing pad used for polishing still maintains a certain flatness, or the polishing pad is directly replaced, and DSP processing is performed under a new condition to find a planarization condition. In the double-side grinding device provided by the embodiment of the invention, because the fixed plate can be prevented from being deformed due to the influence of high temperature in the grinding process, the double-side grinding device provided by the embodiment of the invention does not need to carry out the process when being used for grinding the wafer, thereby prolonging the service life of the grinding pad well, reducing the grinding cost of the wafer and improving the grinding efficiency;

it is worth noting that when the double-side grinding device provided by the embodiment of the invention is used for grinding a wafer, deformation of the fixed plate caused by high temperature in the grinding process can be minimized, so that the deformation efficiency of the first fixed plate structure and the second fixed plate structure is basically consistent, and the grinding speed of the central area and the grinding speed of the edge area of the wafer are basically the same in the grinding process, thereby further improving the flatness of the ground wafer.

In the embodiment of the invention, the double-sided grinding device capable of reducing the thermal deformation of the fixed plate is provided, the fixed plate close to the grinding area is made of ceramics with a low thermal expansion coefficient, and the fixed plate deformation caused by high temperature in the grinding process is avoided, so that the flatness of the wafer is ensured, the grinding process can be continuously carried out, and the grinding efficiency is improved.

In some embodiments of the present invention, a surface of the first fixed disk 3011 facing the second fixed disk 3012 is provided with a first concave-convex structure, a surface of the second fixed disk 3012 facing the first fixed disk 3011 is provided with a second concave-convex structure, a convex portion of the first concave-convex structure extends into a concave portion of the second concave-convex structure and is attached to a bottom of the concave portion of the second concave-convex structure, and a convex portion of the second concave-convex structure extends into the concave portion of the first concave-convex structure and is attached to the bottom of the concave portion of the first concave-convex structure;

a third concave-convex structure is arranged on the surface of the third fixed disc 3021 facing the fourth fixed disc 3022, a fourth concave-convex structure is arranged on the surface of the fourth fixed disc 3022 facing the third fixed disc 3021, a convex portion of the third concave-convex structure extends into a concave portion of the fourth concave-convex structure and is attached to the bottom of the concave portion of the fourth concave-convex structure, and a convex portion of the fourth concave-convex structure extends into a concave portion of the third concave-convex structure and is attached to the bottom of the concave portion of the third concave-convex structure;

as shown in fig. 4 and 5, specific structures of the first concave-convex structure, the second concave-convex structure, the third concave-convex structure and the fourth concave-convex structure are various, and each concave-convex structure exemplarily includes a plurality of convex portions 401, 501 and a plurality of concave portions 402, 502, an orthographic projection of the convex portions on the substrate and an orthographic projection of the concave portions on the substrate are both annular, the convex portions and the concave portions are nested, and the convex portions and the concave portions are alternately distributed along a radius direction of the fixed plate structure;

it is to be noted that the specific distribution of the plurality of convex portions and the plurality of concave portions included in the first concave-convex structure, the second concave-convex structure, the third concave-convex structure and the fourth concave-convex structure, the convex heights of the plurality of convex portions, and the concave depths of the plurality of concave portions may all be set according to actual needs;

for example, the first concave-convex structure may be the same as the fourth concave-convex structure, the second concave-convex structure may be the same as the third concave-convex structure, after the first concave-convex structure and the second concave-convex structure are combined, a region of the first concave-convex structure where the concave portion is provided may correspond to a region of the second concave-convex structure where the convex portion is provided, and a protrusion height of the convex portion of the first concave-convex structure may be set to be the same as a concave depth of the concave portion of the second concave-convex structure.

In the above embodiment of the present invention, the concave-convex structure is arranged between the two fixed disks in the fixed disk structure, so that the two fixed disks can be fixed together, and one fixed disk can drive the other fixed disk to rotate.

In some embodiments of the invention, the double-side lapping apparatus further comprises:

a plurality of first cooling channels located between the first fixed plate 3011 and the second fixed plate 3012, each first cooling channel extending along a radius direction of the first fixed plate structure 301, each first cooling channel being communicated with a first liquid inlet located in a central region of the first fixed plate structure 301, at least one first cooling channel of the plurality of first cooling channels having a first liquid outlet;

at least one annular second cooling channel is formed between the side wall of the convex part of the first concave-convex structure 301 and the side wall of the concave part of the second concave-convex structure, wherein the convex part extends into the side wall of the concave part of the second concave-convex structure, and the second cooling channel is communicated with the plurality of first cooling channels;

the plurality of first cooling channels, the second cooling channels, the first liquid inlet, and the first liquid outlet constitute a first cooling structure 305;

a plurality of third cooling channels located between the third fixed disk 3021 and the fourth fixed disk 3022, each of the third cooling channels extending along a radius direction of the second fixed disk structure 302, each of the third cooling channels being communicated with a second liquid inlet located in a central region of the second fixed disk structure 302, at least one of the third cooling channels having a second liquid outlet;

at least one annular fourth cooling channel is formed between the side wall of the convex portion of the third concave-convex structure 302 and the side wall of the concave portion of the fourth concave-convex structure into which the convex portion extends, and the fourth cooling channel communicates a plurality of third cooling channels.

The plurality of third cooling channels, the fourth cooling channels, the second liquid inlet, and the second liquid outlet form a second cooling structure 306;

illustratively, as shown in fig. 5, the first cooling channel or the third cooling channel is a channel a arranged along the radial direction in fig. 5, the second cooling channel or the third cooling channel is a channel B arranged along the ring shape in fig. 5, each liquid outlet is a point C, and each liquid inlet is a point D;

furthermore, as shown in fig. 6, the first fixed disk 3011 and the second fixed disk 3012 form the first fixed disk structure 301 by a concave-convex structure, and the first cooling structure 305 is disposed between the first fixed disk 3011 and the second fixed disk 3012; as shown in fig. 7, the third fixed plate 3021 and the fourth fixed plate 3022 cooperate to form the second fixed plate structure 302 through a concave-convex structure, and the second cooling structure 306 is disposed between the third fixed plate 3021 and the fourth fixed plate 3022.

In the embodiment of the invention, the two fixed plates are matched to form the cooling liquid pipeline, and the cooling liquid can be introduced into the pipeline in the grinding process, so that the grinding temperature is better reduced, and the thermal deformation of the fixed plates is prevented.

In some embodiments of the invention, the double-side lapping apparatus further comprises:

and the cooling liquid conveying structure is communicated with the first liquid inlet, the second liquid inlet, the first liquid outlet and the second liquid outlet respectively, and is used for injecting cooling liquid into the first liquid inlet and the second liquid inlet and recovering the cooling liquid from the first liquid outlet and the second liquid outlet.

In the embodiment of the invention, the cooling liquid conveying structure is connected with the liquid inlets, can convey cooling liquid to the cooling channels, and is also connected with the liquid outlets, can receive the cooling liquid flowing through the cooling channels, realizes the recycling of the cooling liquid, and is beneficial to saving the cost and protecting the environment.

In some embodiments of the invention, the double-side lapping apparatus further comprises:

a sun gear arranged at the central part of the grinding area;

the ring gear is arranged at the peripheral part of the grinding area;

the carrier is arranged in the grinding area, a bearing hole for supporting the base material to be ground is formed in the carrier, peripheral teeth are arranged on the edge of the carrier, and the peripheral teeth are meshed with the tooth parts of the sun gear and the tooth parts of the ring gear respectively;

the first fixed disk structure 301 and the second fixed disk structure 302 rotate to drive the sun gear, the ring gear and the carrier to rotate.

Specifically, in the grinding process, the rotation directions of the first fixed disk structure 301 and the second fixed disk structure 302 are opposite, and the first fixed disk structure 301 and the second fixed disk structure 302 rotate to drive the sun gear, the ring gear and the carrier to rotate, so that the carrier simultaneously performs rotation and revolution around the sun gear, and thus the grinding pads on the first fixed disk structure 301 and the second fixed disk structure 302 grind two surfaces of the wafer on the carrier.

In the embodiment of the invention, the sun gear and the ring gear have different rotation ratios, so that the carrier can be driven to rotate around the center of the fixed plate and simultaneously be driven to rotate, and the friction efficiency between the base material to be ground and the grinding pad on the fixed plate is increased.

In some embodiments of the present invention, the second fixed plate 3012 and the third fixed plate 3021 are made of silicon carbide ceramic, and the thermal expansion coefficient of the silicon carbide ceramic is 3.7 × 10^-6/℃；

Wherein the silicon carbide ceramic may also have the following mechanical properties: vickers hardness number of 23.0kgf/mm²Bending strength of 450MPa, Young's modulus of 440MPa, Poisson's ratio of 0.17, and fracture toughness of 2-3MPa mm^1/2。

In the embodiment of the invention, the silicon carbide ceramic with certain mechanical properties is adopted as the material of the second fixed plate and the third fixed plate, so that the second fixed plate and the third fixed plate close to the grinding area can be well prevented from being deformed due to high temperature, and the grinding quality is ensured.

In some embodiments of the present invention, the first fixed disk 3011 and the fourth fixed disk 3022 are made of stainless steel.

In the embodiment of the invention, the first fixed disc and the fourth fixed disc are connected with fixing devices such as a table top and the like, and stainless steel is used as the material of the first fixed disc and the fourth fixed disc, so that the first fixed disc and the fourth fixed disc are convenient to connect with other devices, and the fixing effect is good.

In some embodiments of the invention, the double-side lapping apparatus further comprises:

and a driving structure connected to the first fixed disk 3011 and the fourth fixed disk 3022, and configured to control the first fixed disk structure 301 and the second fixed disk structure 302 to rotate.

In the above embodiment of the present invention, the driving structure is connected to the first fixed disk and the fourth fixed disk, and during the polishing process, the two fixed disk structures are driven to rotate, so as to polish the substrate to be polished.

Based on the same invention idea, an embodiment of the present invention further provides a double-side polishing method applied to any one of the double-side polishing apparatuses described above, where when the double-side polishing apparatus includes a sun gear, a ring gear, and a carrier, the double-side polishing method includes:

the first fixed disk structure 301 and the second fixed disk structure 302 rotate to drive the sun gear and the ring gear to rotate, and the sun gear and the ring gear drive the carrier to rotate relative to the first fixed disk structure 301 and the second fixed disk structure 302 through the peripheral teeth on the edge of the carrier;

the first polishing pad 303 in the first fixed disk structure 301 and the second polishing pad 304 in the second fixed disk structure 302 polish the surface of the substrate to be polished disposed on the carrier.

In the embodiment of the invention, the double-sided grinding device with the ceramic fixed disc with low thermal expansion coefficient is adopted to grind the base material to be ground, so that the phenomenon that the fixed disc is deformed due to high temperature generated in the grinding process is avoided, and the flatness of the ground wafer is effectively ensured.

In some embodiments of the present invention, when the double-side polishing apparatus further includes a first cooling passage, a second cooling passage, a third cooling passage, and a fourth cooling passage, the double-side polishing method further includes:

during grinding, cooling liquid is input from a cooling liquid inlet of the first cooling channel, flows through each first cooling channel and flows out from a cooling liquid outlet pipeline in the first cooling channel; meanwhile, cooling liquid is input from a cooling liquid inlet of each second cooling channel, flows through each second cooling channel and flows out from a cooling liquid outlet pipeline in the second cooling channel.

In the embodiment of the invention, the cooling channel is arranged between the two fixed plates of the fixed plate structure, and the circulated cooling liquid is introduced into the cooling channel in the grinding process, so that the effect of reducing the grinding temperature is effectively achieved, the thermal deformation of the fixed plates is avoided, and the circulated cooling liquid can effectively save the cost and protect the environment.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.