Bionic friction-increasing pad for fixing wafer in CMP (chemical mechanical polishing) process

Abstract

The utility model discloses a bionic friction-increasing pad for fixing a wafer in a CMP (chemical mechanical polishing) process, which comprises a supporting layer and a microstructure array layer, a straight column array with an arc-shaped bulge at the tail end forms an effect of tearing off the edge of a contact surface when the straight column array is subjected to normal tension, and the viscosity reduction and desorption are realized. According to the bionic friction increasing pad, the proportion distribution of the two arrays is controlled, so that the effective contact area between materials and the interaction surfaces of the materials is controlled, and the adhesion force between the two surfaces is allowed to be maintained in a moderate range. The two mechanisms are beneficial to effective grabbing and releasing of wafers before and after CMP polishing. Meanwhile, the straight column array of the arc-shaped protrusions of the microstructure array can make contact with the micro-recesses in the surface of the wafer to form mechanical interlocking, the friction performance of the friction increasing pad is effectively guaranteed, and the mechanism effectively prevents the wafer from tangentially sliding in the CMP polishing process. According to the design of the utility model, the fixing requirement of the wafer in the CMP polishing process can be met.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, and particularly relates to a bionic friction-increasing pad for wafer fixation during the CMP polishing process. Background Technique

[0002] Semiconductors are the basic components of modern electronic devices. Almost all electronic products require the use of semiconductor chips, including smartphones, computers, tablets, automobiles, household appliances, etc. The development of the semiconductor industry directly supports the infrastructure of modern society and the convenience of daily life. CMP polishing is a crucial process step in semiconductor manufacturing. This process step can improve the flatness and smoothness of the wafer surface, remove residual impurities and damaged layers, and adjust the electrical properties of the wafer surface. During the CMP polishing process, the fixation of the wafer is very important because it directly affects the quality, uniformity, and efficiency of polishing. Due to the fragile and surface-sensitive characteristics of the wafer, providing a reliable wafer fixation technology during the polishing process can prevent wafer damage and reduce the residual internal stress of the wafer, ensure the surface quality of the wafer, and thus ensure the quality and efficiency of polishing. Therefore, during the CMP polishing process, traditional fixation methods pose a series of challenges.

[0003] Patent CN112234008B proposes a mechanical clamping and transportation mechanism for CMP polishing wafers. This mechanism drives the first jaw group and the second jaw group away through a jaw driving device, and drives the first jaw group and the second jaw group to approach each other through an elastic member to achieve the clamping of the wafer. The setting of the elastic member can accelerate the closing speed of the jaws and improve work efficiency, and has the advantages of high stability and simple operation, but it is easy to cause surface damage and uneven stress distribution to the wafer. Patent CN214135525U proposes a vacuum system for CMP polishing wafers. This system realizes functions such as vacuum detection and monitoring, aggregation and collection of pipeline solutions, and automatic purging of pipelines, improves the pipeline vacuum degree, and fixes the wafer on the polishing head by vacuum adsorption, and has the advantages of good stability and high reliability, but the required equipment cost is high and the operation is complex. Patent CN104369085A proposes a paraffin fixation method for CMP polishing wafers. This method directly adheres the wafer to be polished and the glass sheet, and adopts the method that the paraffin bonding area is only in the through-hole area of the glass sheet, which shortens the time for the melted liquid wax to fully penetrate. This method improves the CMP paraffin fixation efficiency, and has the advantages of high consistency and reliability, and easy implementation of the process. However, the procedures involved in paraffin fixation are cumbersome, and chemical residues are easily formed on the wafer surface. Therefore, it is crucial to find a new CMP polishing wafer fixation method. Summary of the Utility Model

[0004] The purpose of the present utility model is to provide a bionic friction-increasing pad for wafer fixation during the CMP polishing process, aiming to obtain a CMP polishing wafer fixation product that is more stable, reliable and causes less damage to the wafer surface.

[0005] To achieve the above object, the present utility model proposes the following technical solution: A bionic friction-increasing pad for wafer fixation during the CMP polishing process, comprising:

[0006] A support layer;

[0007] A micro-structure array layer, the micro-structure array layer is integrally formed with the support layer, the micro-structure array layer includes a first straight column array and a second straight column array, both the first straight column array and the second straight column array include a number of straight column bodies, the end of the straight column body of the first straight column array is an arc-shaped protrusion, and the end of the straight column body of the second straight column array is a plane.

[0008] Further, in the present utility model, the micro-structure array layer is arranged in an array on the support layer, and the array arrangement methods include one or more of hexagonal close-packed arrangement, circular close-packed arrangement, triangular close-packed arrangement, and rectangular close-packed arrangement.

[0009] Further, in the present utility model, the discrete distribution of the first straight column array and the second straight column array is uniform discrete distribution and non-uniform discrete distribution, and the ratio of the two arrays can be freely adjusted.

[0010] Further, in the present utility model, the convex curvature of the arc-shaped protrusion at the end of the straight column body is between 4000 and 12000 m-1.

[0011] Further, in the present utility model, the size of the micro-structure array layer is at the centimeter level and below the centimeter level, and the aspect ratio is in the range of 0-1.

[0012] Further, in the present utility model, the cross-section of the straight column body includes a circle, a square, a hexagon or a polygon.

[0013] Further, in the present utility model, the materials for making the micro-structure array layer and the support layer are high molecular organic polymers.

[0014] Further, in the present utility model, the high molecular organic polymers include polydimethylsiloxane and fluororubber.

[0015] Beneficial effects, the technical solution of this application has the following technical effects:

[0016] The micro-structure array includes two different structural morphologies: the first is a straight column array with a circular arc-shaped protrusion at the end, which mainly functions to increase friction; the second is a straight column array with a flat end, which mainly functions to adhere. When the straight column array with a circular arc-shaped protrusion at the end is subjected to a normal tensile force, the effect of peeling at the edge of the contact surface is formed, realizing reduced adhesion and detachment. The advantages of the present utility model are as follows: The bionic friction-increasing pad has excellent performance, is convenient to use, can better guarantee the surface quality of the wafer compared with the existing CMP wafer fixing method, reduce the residual internal stress, is simpler and more convenient to use, has a lower cost, and can also customize the shape of the bionic friction-increasing pad according to the size of the wafer and the required fixing force. The bionic friction-increasing pad designed by the present utility model can be used for fixing fragile wafers in CMP. In addition, it can also be used in other similar industries, such as the fixing of glass processing in the glass industry. It has good promotion prospects and economic value.

[0017] It should be understood that all combinations of the foregoing concepts and additional concepts described in greater detail below can be regarded as part of the inventive subject matter of the present disclosure as long as such concepts do not conflict with each other.

[0018] The foregoing and other aspects, embodiments, and features of the teachings of the present utility model can be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present utility model, such as the features and / or beneficial effects of exemplary embodiments, will be apparent from the following description or will be learned through the practice of specific embodiments according to the teachings of the present utility model. Brief Description of the Drawings

[0019] The drawings are not intended to be drawn to scale. In the drawings, each identical or approximately identical component shown in each figure may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the present utility model will be described by way of example and with reference to the drawings, wherein:

[0020] Figure 1 It is a schematic structural diagram of the present utility model.

[0021] In the figure, the meanings of the respective reference numerals are as follows: 1, support layer; 2, micro-structure array layer. Detailed Description of the Specific Embodiment

[0022] To better understand the technical content of the present utility model, specific embodiments are hereby given and described in conjunction with the accompanying drawings as follows. In this disclosure, aspects of the present utility model are described with reference to the drawings, and many illustrative embodiments are shown in the drawings. The embodiments of this disclosure do not necessarily define all aspects of the present utility model. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed in the present utility model are not limited to any implementation manner. Additionally, some aspects disclosed in the present utility model can be used alone, or in any suitable combination with other aspects disclosed in the present utility model.

[0023] This embodiment provides a bionic friction-increasing pad for wafer fixation during the CMP polishing process. The inspiration comes from the van der Waals force and mechanical locking force generated between the microstructure with terminal protrusions on the locust foot and the contact surface. Among them, the van der Waals force provides adhesion, and the mechanical locking force provides friction. By mimicking the adhesion and friction mechanisms of the locust foot, we designed a novel bionic friction-increasing pad with excellent functions. One side surface of it has a microstructure array. The side with the microstructure array is the working surface for increasing friction and reducing adhesion, and the side without structure is the fixing functional area. An adhesive can be used to fix the side without structure to the CMP polishing head to realize the assembly and application of the bionic friction-increasing pad. The present utility model has excellent performance and is convenient to use. Compared with the existing wafer fixation methods for CMP polishing, it can better ensure the surface quality of the wafer and reduce stress residue, and the required cost is lower. It has good promotion prospects and economic value.

[0024] As Figure 1 shown, the fixing functional area is improved, changing from the common current methods such as mechanical clamping, vacuum adsorption, and paraffin bonding to using intermolecular forces and microstructure mechanical locking forces for fixation. There is no need to equip complex clamping equipment, vacuum equipment, or paraffin bonding equipment. A polymer material is used to mimic the adhesion and friction mechanisms of the locust foot, making full use of the van der Waals force and mechanical locking force to fabricate the surface with structures as the wafer fixation functional area.

[0025] Specifically, a bionic friction-increasing pad for wafer fixation during the CMP polishing process includes a support layer 1 and a microstructure array layer 2. The microstructure array layer 2 is the fixing functional area. The microstructure array layer 2 includes several straight columns, and the cross-section of the straight columns includes a circle, a square, a hexagon, or a polygon, etc.

[0026] The microstructure array layer 2 includes a first straight column array and a second straight column array. The first straight column array and the second straight column array have two different structural morphologies. The first straight column array is a straight column array with an arc-shaped protrusion at the end, and the end of the second straight column array is a straight column with a flat surface. The two arrays can be regularly distributed or discretely distributed.

[0027] The first straight post array and the second straight post array are arranged in an array on the support layer 1, which can be a hexagonal close-packed arrangement, a circumferential close-packed arrangement, a triangular close-packed arrangement, a rectangular close-packed arrangement, etc.

[0028] Furthermore, the bionic friction-increasing pad is integrally formed, and the material can be a polymer such as polydimethylsiloxane and fluororubber.

[0029] Furthermore, the size of the micro-structure array layer 2 is at the centimeter level and below, the aspect ratio is in the range of 0-1, and the convex curvature of the arc-shaped protrusion is between 4000 and 12000 m-1.

[0030] Furthermore, the chemical composition of the material of the bionic friction-increasing pad is stable after being completely formed, and it is not easy to leave residual marks on the wafer surface under the working environment.

[0031] According to the above design, the innovation of the present utility model lies in that: the micro-structure array layer 2 includes two different structural morphologies: the first is a straight post array with an arc-shaped protrusion at the end, which mainly plays a role in increasing friction; the second is a straight post array with a flat end, which mainly plays an adhesion role. The straight post array with an arc-shaped protrusion at the end forms the effect of tearing at the edge of the contact surface when subjected to a normal tensile force, realizing reduced adhesion and detachment. The advantages of the present utility model are as follows: the bionic friction-increasing pad has excellent adhesive performance and is easy to use. Compared with the existing CMP wafer fixing method, it can better guarantee the surface quality of the wafer, reduce the residual internal stress, is simpler and more convenient to use, has a lower cost, and can also customize the shape of the bionic friction-increasing pad according to the size of the wafer and the required fixing force. The bionic friction-increasing pad designed by the present utility model can be used for fixing fragile wafers in CMP. In addition, it can also be used in other similar industries, such as the fixing of glass processing in the glass industry. It has good promotion prospects and economic value.

[0032] Although the present utility model has been disclosed above with preferred embodiments, it is not intended to limit the present utility model. Those with ordinary knowledge in the technical field to which the present utility model belongs can make various modifications and refinements without departing from the spirit and scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to what is defined by the claims.

Claims

1. A bionic friction-increasing pad for wafer fixation during CMP polishing, characterized in that: include: Support layer; A microstructure array layer, wherein the microstructure array layer is integrally formed with the support layer, and the microstructure array layer comprises a first straight column array and a second straight column array, wherein the first straight column array and the second straight column array both comprise a plurality of straight columns, wherein the ends of the straight columns of the first straight column array are arc-shaped protrusions, and the ends of the straight columns of the second straight column array are flat surfaces.

2. The bionic friction-enhancing pad for wafer fixation during CMP polishing according to claim 1, characterized in that: The microstructure array layer is arranged on the support layer in an array, and the array arrangement includes one or more of hexagonal close-packed arrangement, circular close-packed arrangement, triangular close-packed arrangement, and rectangular close-packed arrangement.

3. The bionic friction-enhancing pad for wafer fixation during CMP polishing according to claim 1, characterized in that: The discrete distribution of the first straight column array and the second straight column array is uniform discrete distribution and non-uniform discrete distribution, and the ratio of the two arrays can be freely adjusted.

4. The bionic friction-enhancing pad for wafer fixation during CMP polishing according to claim 1, characterized in that: The curvature of the arc-shaped protrusion at the end of the straight cylinder is between 4000 and 12000 m-1.

5. The bionic friction-enhancing pad for wafer fixation during CMP polishing according to claim 1, characterized in that: The size of the microstructure array layer is at or below the centimeter level, and the aspect ratio is in the range of 0-1.

6. The bionic friction-enhancing pad for wafer fixation during CMP polishing according to claim 1, characterized in that: The cross section of the straight column includes a circle, a square or a hexagon.

7. The bionic friction-enhancing pad for wafer fixation during CMP polishing according to claim 1, characterized in that: The microstructure array layer and the support layer are made of high molecular organic polymer.

8. The bionic friction-enhancing pad for wafer fixation during CMP polishing according to claim 7, characterized in that: The high molecular organic polymer includes polydimethylsiloxane and fluororubber.

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