CN117207059A

CN117207059A - Wafer thinning carrier, manufacturing method and application thereof

Info

Publication number: CN117207059A
Application number: CN202311184995.7A
Authority: CN
Inventors: 韩小朋; 柴利林; 彭虎
Original assignee: Suzhou Longchi Semiconductor Technology Co ltd
Current assignee: Suzhou Longchi Semiconductor Technology Co ltd
Priority date: 2023-09-14
Filing date: 2023-09-14
Publication date: 2023-12-12

Abstract

The application discloses a wafer thinning carrier, a manufacturing method and application thereof. The wafer thinning carrier body comprises a carrier body, the carrier body is provided with a plurality of protruding portions, the protruding portions are sequentially arranged at intervals along the circumferential direction of the carrier body, the protruding portions enclose to form a containing groove for containing a wafer, the wafer can be arranged in the containing groove, and the thickness of the wafer is larger than the depth of the containing groove. The protruding parts on the carrier body of the wafer thinning carrier body are distributed in a trapezoid shape, so that larger abrupt change of stress in grinding can be avoided, wafer fragments are further avoided, and the problem of non-uniformity in grinding is further avoided. The wafer thinning method is carried out by using the wafer thinning carrier body provided by the application, the process is predicted to be finished according to the change of force, and the wafers on the carrier body used by the wafer thinning carrier body are distributed like a trapezoid, so that the stress in the grinding process can not generate larger abrupt change, the stability of the process can be maintained, and the abrupt change of the power of grinding equipment is prevented.

Description

Wafer thinning carrier, manufacturing method and application thereof

Technical Field

The application relates to a wafer thinning carrier, a manufacturing method and application thereof, and belongs to the technical field of semiconductors.

Background

As is well known, with the application of large-scale and ultra-large-scale integrated circuits, there is a growing demand for miniaturization, weight saving and multi-functionalization of devices, so that the demand for ultra-thin chips is increasing. Currently, the method is applied to ultrathin chips in the fields of memory chips, multi-chip packaging and the like.

The thinner the device is for certain materials, the better its heat dissipation, but the desire to make thinner devices is also a significant challenge for the production process. Fragments are easily generated during grinding of thinner devices, resulting in a decrease in yield. In the method for improving the grinding yield of the warped sapphire wafer disclosed by the publication No. CN112542373A, in order to reduce fragments in the thinning of the sapphire, a grooving mode is adopted on the first surface and the second surface, so that the grooving plays a role in heat dissipation, and in addition, the stress generated in the grinding process is released, so that the fragments in the grinding process are reduced. But only for thinning of wafers above 120um in thickness, nothing is said about thinning of thinner wafers. In addition, in the "method for optimizing bonding and thinning of semiconductor wafer" with publication number of CN104658927a, "thinning is performed after bonding, but the method has the disadvantages of complex process, high implementation difficulty, difficult debonding, and the like.

Disclosure of Invention

Aiming at the defects of the prior art, the application aims to provide a wafer thinning carrier, a manufacturing method and application thereof.

In order to achieve the purpose of the application, the technical scheme adopted by the application comprises the following steps:

the application provides a wafer thinning carrier body, comprising: the carrier comprises a carrier body, a containing groove and a plurality of protruding parts; the carrier body is provided with a first surface and a second surface which are opposite; the accommodating groove is formed on the first surface of the carrier body and is used for accommodating a wafer; the plurality of protruding parts are arranged on the first surface of the carrier body at intervals and distributed around the accommodating groove.

In an embodiment, the size of the protruding portion in the first direction gradually decreases along a second direction, wherein the first direction is parallel to the first surface of the carrier body, and the second direction is perpendicular to the first direction and gradually away from the carrier body.

In a specific embodiment, the boss is trapezoidal.

In a specific embodiment, the carrier body is made of any one of sapphire, SIC or Si.

In a specific embodiment, the accommodating groove is circular, the plurality of protruding portions are uniformly distributed at the edge of the accommodating groove, and the central angle corresponding to each protruding portion is 30-45 °.

In a specific embodiment, the central angle between two adjacent protruding parts is 10-30 degrees.

In a specific embodiment, the height of the raised portion is greater than the thickness of the wafer.

In a specific embodiment, the sum of the depth of the accommodating groove and the height of the protruding portion is smaller than or equal to the thickness of the wafer, and the depth of the accommodating groove is larger than the thickness of the wafer thinned to the set thickness value.

The application also provides a preparation method of the wafer thinning carrier, which comprises the following steps:

providing a carrier body, wherein the carrier body is provided with a first surface and a second surface which are opposite;

forming a containing groove on the first surface of the carrier body, wherein the containing groove is used for containing a wafer;

a plurality of protruding parts are formed on the first surface of the carrier body in a machining mode at intervals, and the protruding parts are arranged around the accommodating groove.

The application also provides wafer thinning equipment, which comprises a grinding mechanism and the wafer thinning carrier, wherein the grinding mechanism is used for grinding a wafer, and the wafer is fixed in the wafer thinning carrier.

In a specific embodiment, the wafer thinning apparatus further comprises a force sensing mechanism coupled to the polishing mechanism and configured to detect at least a change in polishing force during polishing.

The application also provides a wafer thinning method, which comprises the following steps: providing the wafer thinning carrier, and fixing a wafer to be thinned in a containing groove of the wafer thinning carrier;

and grinding the wafer until the thickness of the wafer is thinned to a set thickness value.

In a specific embodiment, the wafer and the protruding portion are polished, the polishing force is continuously monitored in the polishing process, and when the polishing force reaches a preset threshold value, the thickness of the wafer is determined to reach a set thickness value.

Compared with the prior art, the application has the advantages that:

1) The bulge is arranged on the wafer thinning carrier body, so that larger abrupt change of stress in grinding can not occur, the stability of a process can be maintained, abrupt change of power of grinding equipment is prevented, and wafer fragments and uneven grinding problems are further avoided;

2) According to the wafer thinning method provided by the application, the protruding part arranged along the circumferential direction of the carrier body can play a role in monitoring the grinding thickness, and in the process of grinding the wafer to the set thickness, particularly when the wafer is ground from the pretreatment thickness to the set thickness, the grinding force can be changed, and the process can be predicted to be finished according to the change of the force; and wafers on the carrier body are distributed like trapezoids, so that larger abrupt change of stress in grinding can not occur, the stability of the process can be maintained, abrupt change of power of grinding equipment is prevented, and the problems of wafer fragments and grinding nonuniformity are avoided.

Drawings

FIG. 1 is a schematic diagram of a wafer thinning carrier according to the present application;

FIG. 2 is a top view of a wafer thinning carrier of FIG. 1;

FIG. 3 is a schematic view of a protrusion of the wafer thinning carrier of FIG. 1;

FIG. 4 is a schematic diagram of another wafer thinning carrier according to the present application;

FIG. 5 is a schematic diagram of bonding a wafer thinning carrier and a wafer to be thinned according to the present application;

FIG. 6 is a process flow diagram of a wafer thinning method according to the present application;

reference numerals illustrate: 1. a carrier body; 11. a receiving groove; 12. a boss.

Detailed Description

In view of the shortcomings in the prior art, the inventor of the present application has long studied and practiced in a large number of ways to propose the technical scheme of the present application. The technical scheme, the implementation process, the principle and the like are further explained as follows.

Example 1

Referring to fig. 1, in order to provide a wafer thinning carrier body 1 in this embodiment, as shown in fig. 1, the carrier body 1 has a first surface and a second surface opposite to each other, and the accommodating groove 11 is formed on the first surface of the carrier body 1 and is used for accommodating a wafer; the plurality of protruding portions 12 are disposed on the first surface of the carrier body 1 at intervals, and are distributed around the accommodating groove 11. A spacing groove is formed between any two adjacent convex parts 12. The wafer thinning carrier body 1 provided by the application can be used for thinning the wafer, and in the thinning process, the thickness of the polished wafer is gradually reduced from the first surface of the carrier body 1 to the second surface of the carrier body 1, and the raised parts 12 arranged on the carrier body 1 can enable the polishing stress to be dispersed, reduce the risk of fragments possibly occurring in the polishing process, and improve the uniformity of the polished product.

Referring to fig. 3, the dimension of the protruding portion 12 in the first direction is gradually reduced along the second direction, wherein the first direction is parallel to the first surface of the carrier body 1, and the second direction is perpendicular to the first direction and gradually away from the carrier body 1. Specifically, the protruding portion 12 may have a trapezoid shape, and the size of the trapezoid in the first direction gradually decreases along the second direction.

Specifically, the carrier body 1 is a carrier body 1 made of any one of sapphire, SIC or Si. Preferably, the carrier body 1 is a carrier body 1 made of sapphire material.

More specifically, the shape of the wafer is mostly circular, the accommodating groove 11 is also circular in accordance with the shape of the wafer, and the plurality of protruding portions 12 are uniformly distributed at the edge of the accommodating groove 11.

As shown in fig. 3, the central angle corresponding to each protruding portion 12 is 30 ° to 45 °, and as shown in fig. 2, the central angle between two adjacent protruding portions 12 is 10 ° to 30 °. Too little make machining efficiency reduce, the degree of difficulty increases, and the angle is too big for protruding dispersed stress effect key weakens, makes the piece risk increase.

Example 2

The present embodiment provides a wafer thinning carrier, which has a structure substantially similar to that of embodiment 1, and is different in that the shape of the appearance of the protruding portion 12 may be a regular shape or an irregular shape, and the outer surface of the protruding portion 12 may be a plane, a curved surface, or a combination of the plane and the curved surface, so that the shape thereof becomes a regular shape or an irregular shape. The regular shapes include quasi-circular, trapezoidal, triangular, etc. Of course, the shape of the material may be other regular polygons or a part of other regular polygons.

Referring to fig. 3, the protruding portion 12 is a trapezoid, and the central angle of the trapezoid is 35 °, compared with the triangular protruding portion 12: the upper surface of the trapezoid is provided with a certain area, when the grinding reaches the upper surface of the trapezoid, the contact area is relatively large, the contact stress is smaller than that of the triangle, and the edge pattern in the grinding is not easy to break.

On the premise of ensuring the processing quality, the trapezoid height is generally set to be 1.2-2 times of the set thickness of the required product in order to ensure the processing efficiency. Specifically, when the thickness of the wafer is reduced to a set thickness value, the set thickness value is 50um, and the height of the trapezoid is 60-100um, because when the trapezoid is set higher, the processing efficiency can be reduced, and when the thickness is set below 1.2 times of the set thickness, the processing difficulty of the trapezoid of the carrier is increased, and the stability of the carrier cannot be ensured.

In a preferred embodiment, the protruding portion 12 may be trapezoid-like, the protruding portion 12 has two side surfaces, both of the side surfaces are disposed at an angle with the first surface of the carrier body 1, and the angles between the two side surfaces and the first surface of the carrier body 1 may be the same. And the included angle between the two side surfaces is the central angle corresponding to the protruding part 12, and the central angle can be 30-45 degrees.

Preferably, both sides of the boss 12 may be planar. It will be appreciated that the projection 12 approximates an isosceles trapezoid in appearance. The included angle between the two side surfaces is 30-45 degrees.

In a preferred embodiment, the plurality of protrusions 12 are uniformly arranged at intervals along the circumferential direction of the carrier body 1. The trapezoid is uniformly arranged, so that the stress of the wafer is uniform during grinding, and fragments caused by uneven stress distribution during grinding are prevented.

In this embodiment, the protruding portion 12 of the wafer thinning carrier body 1 is distributed in a trapezoid shape, so that the stress in the grinding process can not generate larger abrupt change, thus the stability of the process can be maintained, the abrupt change of the power of the grinding equipment can be prevented, and the wafer fragments and the problem of non-uniformity of grinding can be further avoided.

Example 3

The present embodiment provides a wafer thinning carrier, which has a structure substantially similar to that of embodiment 1 or embodiment 2, wherein in this embodiment, the height of the protrusion 12 is greater than the thickness of the wafer, which can be understood that the wafer placed on the carrier body 1 is at least partially protruded from the protrusion 12, when the carrier body 1 carries the wafer for thinning, the polishing work can be performed on the wafer first, and then the polishing force of the wafer and the carrier body 1 will change together, so that the process is predicted to be about to end according to the change of the force.

In this embodiment, the accommodating groove 11 may be provided as shown in fig. 1, where the depth of the accommodating groove 11 is the same as the height of the protruding portion 12.

Of course, as shown in fig. 4, the accommodating groove 11 may be formed by sinking on the first surface of the carrier body 1, where the depth of the accommodating groove 11 is greater than the height of the protruding portion 12, and at least a portion of the wafer may still be embedded into the accommodating groove 11 when the polishing process is nearly performed, so as to further avoid the risk of the wafer being broken during the polishing process.

Example 4

The present embodiment provides a method for manufacturing a wafer thinning carrier, which can be applied to manufacturing the wafer thinning carrier in any of the above embodiments, and includes the following steps:

providing a carrier body l, wherein the carrier body l is provided with a first surface and a second surface which are opposite;

a containing groove 11 is formed on the first surface of the carrier body 1, and the containing groove 11 is used for containing a wafer;

a plurality of protruding portions 12 are formed on the first surface of the carrier body 1 in a machining manner, and the protruding portions 12 are arranged around the accommodating groove 11.

Specifically, the first surface of the body may be grooved to form a receiving groove 11, the wafer shape is mostly circular, and the shape of the receiving groove 11 is similar to that of the wafer to be thinned, so that the receiving groove 11 may be circular, and an annular protrusion edge is disposed around the receiving groove 11. Further, a plurality of spacing grooves are formed on the edge of the annular protruding portion, protruding portions 12 are formed among the plurality of spacing grooves, and the protruding portions 12 and the spacing grooves are alternately arranged in sequence. Of course, the steps of forming the accommodating groove 11 and the spacing groove are taken as an example of the preferred steps, and in order to form the carrier body 1 provided by the present application, the spacing groove may be formed at the edge of the body first, and then the accommodating groove 11 is formed in the middle of the body, so that the steps of thinning the wafer carrier described in embodiment 1 and embodiment 3 are all within the protection scope of the present application.

Example 5

The embodiment provides wafer thinning equipment, which comprises grinding equipment and the wafer thinning carrier in embodiment 1, wherein the grinding mechanism is used for grinding a wafer, and the wafer is fixed in the wafer thinning carrier. Specifically, a wafer to be thinned is disposed in the accommodating groove 11 of the carrier body 1, and the polishing apparatus can perform thinning processing on the wafer. The wafer thinning device further comprises a bonding machine and a force sensing mechanism, wherein the bonding machine is used for bonding the wafer with the carrier body 1 so that the wafer is fixed in the accommodating groove 11 of the carrier body 1, and the force sensing mechanism is connected with the grinding mechanism and is at least used for detecting the change of grinding force in the grinding process.

Example 6

As shown in fig. 3, the present embodiment provides a wafer thinning method, which specifically includes the following steps:

providing the wafer thinning carrier according to any of the above embodiments, and fixing a wafer to be thinned in the accommodating groove 11 of the wafer thinning carrier;

providing a wafer, performing a temporary bonding process on the carrier body 1 and the wafer, so that the wafer is fixed with the carrier body 1, and grinding the wafer until the thickness of the wafer is thinned to a set thickness value.

Thinning the wafer to the pre-processing thickness means thinning the wafer after being fixed with the carrier body 1 until the upper surface of the wafer is flush with the upper surface of the boss 12, and then thinning the wafer and the carrier body 1 simultaneously to the set thickness. Wherein, the set thickness is smaller than the depth of the accommodating groove 11 of the carrier body 1.

Referring to fig. 5-6, it is easy to understand that in step a, a carrier body 1 and a wafer are provided, wherein a receiving groove 11 and a spacing groove are formed on a first surface of the carrier body 1. In step b, the carrier body 1 is bonded to the wafer. In the method, a-b-c-d step can be performed to perform thinning treatment, wherein the wafer is thinned to a pre-treatment thickness in step c, and then the wafer and the carrier body 1 are thinned to a set thickness as shown in step d.

Further, the set thickness is 20um to 60um. Compared with the prior art, the wafer thinning method provided by the embodiment can be used for thinning the wafer and obtaining a thinner wafer.

Further, in the method, a laser stripping process, a dry etching process or a wet etching process is adopted to perform slotting treatment on the carrier body 1, and a containing groove 11 is formed on the first surface of the carrier body 1.

Preferably, the carrier body 1 is circular, the transverse section of the accommodating groove 11 is circular, and the accommodating groove 11 and the carrier body 1 are concentrically arranged. After the carrier body 1 is subjected to the grooving process, a containing groove 11 and an annular protruding part edge formed around the containing groove 11 are formed on the carrier body 1.

Further, in the method, a laser stripping process, a dry etching process or a wet etching process is adopted, a spacing groove is formed on the edge of the annular protruding part of the carrier body 1, and a plurality of protruding parts 12 which are arranged at intervals are formed on the first surface of the carrier body 1; and thinning the wafer by adopting a mechanical grinding mode. The wafer is thinned by adopting the mode of mechanically grinding the silicon carbide grinding wheel, and the thinning degree of the wafer can be fed back based on the strength detection result during grinding.

Taking the 6-hour sapphire as an example, grinding the set thickness, setting the height of an edge trapezoid to be 75um, setting the height of the edge trapezoid to be 1.5 times of the set thickness, setting interval grooves on the edge of an annular boss of the carrier body 1 to form a plurality of bosses 12 distributed at intervals, wherein the bosses 12 are trapezoid-like, the included angles formed by two sides of the trapezoid are 35 degrees, the interval angle between the trapezoids is 10 degrees, the feeding speed is 1um/s, the grinding force (the vertical direction of a grinding surface) is kept at 100N before the grinding to a trapezoid interface when the rotating speed is 1000rpm, the grinding force is kept at 100N immediately before the grinding to the trapezoid interface, the force is changed from 100N to 112N when the trapezoid upper surface is completely contacted, then the stress is gradually increased along with the increase of the grinding depth, the grinding force is 118N when the grinding depth is 60um, and the grinding force is increased to 134N when the grinding to the final thickness of 50 um.

By using the wafer thinning method provided by the application, the convex part 12 on the carrier body 1 can disperse grinding stress, so that the problem of wafer fragments during grinding is avoided, and the uniformity of the wafer after grinding is improved; the protruding part 12 arranged along the circumferential direction of the carrier body 1 can also play a role in monitoring the grinding thickness, and in the process of grinding the wafer to the set thickness, particularly when the wafer is ground from the pretreatment thickness to the set thickness, the grinding force can be changed, and the process can be predicted to be finished according to the change of the force; the wafer on the carrier body 1 is in trapezoid-like distribution, so that the stress in grinding can not generate larger mutation, the stability of the process can be maintained, the mutation of the power of grinding equipment is prevented, and the problems of wafer fragments and grinding non-uniformity are avoided.

Of course, the wafer manufactured by the wafer thinning method provided by the application also belongs to the protection scope of the application.

Example 7

1. Through dry etching mode, etch out the accommodation groove that diameter is 152mm on the circular sapphire that diameter is 159mm, encircle the annular bellying edge that the accommodation groove formed is high and is 30um, and the degree of depth of accommodation groove is 30um.

2. Spacing grooves are formed in the edges of the annular protruding portions of the carrier body in a photoetching and etching mode, a plurality of protruding portions which are distributed at intervals are formed, wherein the protruding portions are trapezoid-like, the height of each protruding portion is 30um, included angles formed by two sides of each trapezoid are 35 degrees, the spacing angle between the trapezoids is 10 degrees, the height of each trapezoid is 30um, and the carrier body shown in the step a in fig. 6 is formed.

3. The sapphire wafer to be bonded and the processed bonding carrier body are placed on a bonding machine, the bonding temperature is 180 ℃, the bonding pressure is 20N, the dwell time is 150s, and the bonding is carried out as shown in the step b in fig. 6.

4. And thinning the bonded sapphire wafer by using a diamond grinding wheel, wherein the feeding speed of the diamond grinding wheel is 1um/s, the rotating speed of the diamond grinding wheel is 1000rpm, and the set thickness of the thinned sapphire wafer is 20um.

The steps in the example were repeated to perform thinning processing on the wafer 100 times, and sapphire wafer fragments were generated in the thinning processing 7 times in total, and the sapphire wafer fragment rate was 7%.

Example 8

1. Through dry etching mode, etch out the accommodation groove that diameter is 152mm on the circular sapphire that diameter is 159mm, encircle the annular bellying edge that the accommodation groove formed is high and is 45um, and the degree of depth of accommodation groove is 45um.

2. Spacing grooves are formed in the edges of the annular protruding portions of the carrier body in a photoetching and etching mode, a plurality of protruding portions which are distributed at intervals are formed, wherein the protruding portions are trapezoid-like, the height of each trapezoid protruding portion is 45um, an included angle formed by two sides of each trapezoid is 35 degrees, and the spacing angle between the trapezoids is 10 degrees.

3. And placing the sapphire wafer to be bonded and the processed bonding carrier body on a bonding machine, wherein the bonding temperature is 180 ℃, the bonding pressure is 20N, and the pressure maintaining time is 150s.

4. And thinning the bonded sapphire wafer by using a diamond grinding wheel, wherein the feeding speed of the diamond grinding wheel is hm/s, the rotating speed of the diamond grinding wheel is 000rpm, and the set thickness of the thinned sapphire wafer is 30um.

The difference between the present embodiment and embodiment 7 is that the set thickness of the sapphire wafer to be thinned is 30um, and the depth of the accommodating groove of the wafer thinning carrier provided by the present embodiment is 45um.

The steps in the example were repeated to perform thinning processing on the wafer 100 times, and sapphire wafer fragments were generated 5 times in total in the thinning processing, and the sapphire wafer fragment rate was 5%.

Example 9

1. And (3) etching a containing groove with the diameter of 152mm on the round sapphire with the diameter of 159mm in a dry etching mode, wherein the height of the edge of the annular protruding part formed around the containing groove is 75um, and the depth of the containing groove is 75um.

2. Spacing grooves are formed in the edges of the annular protruding portions of the carrier body in a photoetching and etching mode, a plurality of protruding portions which are distributed at intervals are formed, the protruding portions are trapezoid-like, the height of each trapezoid protruding portion is 75um, an included angle formed by two sides of each trapezoid is 35 degrees, and the spacing angle between the trapezoids is 10 degrees.

4. And thinning the bonded sapphire wafer by using a diamond grinding wheel, wherein the feeding speed of the diamond grinding wheel is 1um/s, the rotating speed of the diamond grinding wheel is 1000rpm, and the set thickness of the thinned sapphire wafer is 60um.

The difference between the present embodiment and embodiment 7 is that the set thickness of the sapphire wafer to be thinned is 60um, and the depth of the accommodating groove of the wafer thinning carrier provided by the present embodiment is 75um.

The steps in the example were repeated to perform thinning processing on the wafer 100 times, and sapphire wafer fragments were generated 2 times in total in the thinning processing, and the sapphire wafer fragment rate was 2%.

Comparative example 1

In this embodiment, a wafer thinning manner common in the art is adopted:

1. and etching a containing groove with the diameter of 152mm on the round sapphire with the diameter of 159mm in a dry etching mode, wherein the height of the edge of the annular protruding part formed around the containing groove is 28um, and the depth of the containing groove is 28um.

2. And placing the sapphire wafer to be bonded and the processed bonding carrier body on a bonding machine, wherein the bonding temperature is 180 ℃, the bonding pressure is 20N, and the pressure maintaining time is 150s.

3. And thinning the bonded sapphire wafer by using a diamond grinding wheel, wherein the feeding speed of the diamond grinding wheel is 1um/s, the rotating speed of the diamond grinding wheel is 1000rpm, and the set thickness of the thinned sapphire wafer is 30um. In the thinning treatment process, the gold steel grinding wheel is not contacted with the carrier body.

The difference between the present embodiment and embodiment 8 is that, in this embodiment, a wafer thinning manner common in the art is adopted, where, more specifically, in the common manner, only the wafer to be thinned is thinned, and the depth of the accommodating groove for accommodating the sapphire wafer provided on the wafer thinning carrier is smaller than the set thickness.

The steps in the example were repeated to perform thinning processing on the wafer 100 times, and sapphire wafer fragments were generated 47 times in total in the thinning processing, and the sapphire wafer fragment rate was 47%.

Comparative example 1 has a higher chipping rate than example 8 when the wafer thinning operation is performed in a conventional manner with the same set thickness. By the wafer thinning carrier and the wafer thinning method, thinner wafers can be obtained, the wafer fragment rate is lower in the processing thinning operation, and the processing loss problem is avoided.

Comparative example 2

In this embodiment, the wafer thinning method provided by the application is adopted to perform:

1. through dry etching mode, etch out the accommodation groove that diameter is 152mm on the circular sapphire that diameter is 159mm, encircle the annular bellying edge that the accommodation groove formed is 60um in height, and the degree of depth of accommodation groove is 60um.

2. Spacing grooves are formed in the edges of the annular protruding portions of the carrier body in a photoetching and etching mode, a plurality of protruding portions which are distributed at intervals are formed, wherein the protruding portions are trapezoid-like, included angles formed by two sides of each trapezoid are 35 degrees, the spacing angle between the trapezoids is 10 degrees, the height of each trapezoid is 60um, and the height of each trapezoid is 2 times of the set thickness.

4. And thinning the bonded sapphire wafer by using a diamond grinding wheel, wherein the feeding speed of the diamond grinding wheel is 1um/s, the rotating speed of the diamond grinding wheel is 1000rpm, and the set thickness of the thinned sapphire wafer is 30um. In the thinning treatment process, the gold steel grinding wheel is not contacted with the carrier body.

The steps in the example were repeated to perform thinning processing on the wafer 100 times, and sapphire wafer fragments were generated in the thinning processing 17 times in total, with a sapphire wafer fragment rate of 17%.

In this comparative example, the height of the convex portion was 2 times the set thickness, and the chipping rate was high during processing, as compared with example 8. When the height of the protruding portion is 1.5 times of the set thickness, not only a thinner wafer can be obtained, but also the wafer fragment rate is lower in the process thinning operation.

Comparative example 3

1. through dry etching mode, etch out the accommodation groove that diameter is 152mm on the circular sapphire that diameter is 159mm, encircle the height of the annular bellying edge that the accommodation groove formed is 45um, and the degree of depth of accommodation groove is 45um, is 2 times of settlement thickness.

2. Spacing grooves are formed in the edges of the annular protruding portions of the carrier body in a photoetching and etching mode, a plurality of protruding portions which are distributed at intervals are formed, wherein the protruding portions are triangular, included angles formed by two sides of the triangular portions are 35 degrees, the spacing angle between the triangular portions is 10 degrees, and the triangular height is 30um.

The steps in the example were repeated to perform thinning processing on the wafer 100 times, and sapphire wafer fragments were generated 26 times in total in the thinning processing, and the sapphire wafer fragment rate was 26%.

This comparative example differs from example 8 in that the protrusions are provided in a triangular shape, and since the contact area is small and the contact stress is large when the grinding reaches the upper surface of the triangle, the risk of chipping of the edge pattern increases during the grinding, and therefore in a preferred embodiment, the protrusions are trapezoidal.

Further, when the present comparative example is compared with the comparative example 1, in the case that the set thickness of the thinned sapphire wafer is the same, the breakage rate of the protruding portion of the present comparative example is still lower than that of the conventional method, so that the breakage rate of the wafer can be greatly reduced in the thinning work of the wafer.

It should be understood that the above embodiments are merely for illustrating the technical concept and features of the present application, and are intended to enable those skilled in the art to understand the present application and implement the same according to the present application without limiting the scope of the present application. All equivalent changes or modifications made in accordance with the spirit of the present application should be construed to be included in the scope of the present application.

Claims

1. A wafer thinning carrier, comprising:

the carrier comprises a carrier body (1), a containing groove (11) and a plurality of protruding parts (12); wherein, the carrier body (1) is provided with a first surface and a second surface which are opposite; the accommodating groove (11) is formed on the first surface of the carrier body (1) and is used for accommodating a wafer; the plurality of protruding parts (12) are arranged on the first surface of the carrier body (1) at intervals and distributed around the accommodating groove (11).

2. Wafer thinning carrier body (1) according to claim 1, characterized in that:

the size of the protruding portion (12) in a first direction is gradually reduced along a second direction, the first direction is parallel to the first surface of the carrier body (1), and the second direction is perpendicular to the first direction and gradually away from the carrier body (1).

3. Wafer thinning carrier body (1) according to claim 1, characterized in that:

the convex part (12) is trapezoid;

and/or the carrier body (1) is made of any one material of sapphire, SIC or Si.

4. Wafer thinning carrier body (1) according to claim 1, characterized in that:

the accommodating groove (11) is circular, the plurality of protruding portions (12) are uniformly distributed at the edge of the accommodating groove (11), and the central angle corresponding to each protruding portion (12) is 30-45 degrees.

5. Wafer thinning carrier body (1) according to claim 1, characterized in that:

the height of the protruding part (12) is larger than the thickness of the wafer;

or, the sum of the depth of the accommodating groove (11) and the height of the protruding part (12) is smaller than or equal to the thickness of the wafer, and the depth of the accommodating groove (11) is larger than the thickness of the wafer thinned to the set thickness value.

6. The preparation method of the wafer thinning carrier is characterized by comprising the following steps of:

providing a carrier body (1), wherein the carrier body (1) is provided with a first surface and a second surface which are opposite;

a containing groove (11) is formed on the first surface of the carrier body (1), and the containing groove (11) is used for containing a wafer;

a plurality of protruding parts (12) which are distributed at intervals are formed on the first surface of the carrier body (1) in a machining mode, and the protruding parts (12) are arranged around the accommodating groove (11).

7. A wafer thinning apparatus comprising a grinding mechanism, and further comprising the wafer thinning carrier of any one of claims 1-6, the grinding mechanism being configured to grind a wafer, the wafer being secured within the wafer thinning carrier.

8. The wafer thinning apparatus according to claim 7, wherein:

the grinding machine further comprises a force sensing mechanism, wherein the force sensing mechanism is connected with the grinding mechanism and is at least used for detecting the change of grinding force in the grinding process.

9. A method of thinning a wafer, comprising:

providing a wafer thinning carrier according to any one of claims 1-8 and fixing a wafer to be thinned in a receiving groove (11) of the wafer thinning carrier;

10. The method of claim 9, further comprising:

and grinding the wafer and the protruding part (12), continuously monitoring the grinding force in the grinding process, and judging that the thickness of the wafer reaches a set thickness value when the grinding force reaches a preset threshold value.