A processing pad assembly for wafer grinding equipment and a grinding method

Abstract

The technical solution of the present application discloses a processing pad assembly and a grinding method for a wafer grinding device, wherein the processing pad assembly comprises a first processing pad, a second processing pad and a release adhesive layer, wherein the first processing pad and the second processing pad are bonded and fixed by the release adhesive layer, wherein when grinding the wafer, the first processing pad is used to bond and fix to an upper grinding disc, and the second processing pad is used to bond and fix to a lower grinding disc, and after removing the release adhesive layer, the wafer is placed between the first processing pad and the second processing pad for grinding, and a front downward pressure pasting method is adopted when the first processing pad and the upper grinding disc are bonded and fixed, and when the second processing pad and the lower grinding disc are bonded and fixed, the occurrence rate of bubbles and wrinkles of the processing pad during the pasting process can be greatly reduced by using such a processing pad, thereby effectively reducing the damage to the wafer surface, reducing the breakage rate of the wafer during double-sided processing, and improving the double-sided processing yield.

Description

Technical Field

[0001] The invention relates to the field of wafer processing, and in particular to a processing pad assembly for wafer grinding equipment and a grinding method based on the processing pad assembly. Background Art

[0002] Grinding is the main means of chip surface finishing. Under a certain pressure, the damage on the chip surface is removed through the interaction between the abrasive and the chip surface, and finally the chip surface is slightly damaged or undamaged.

[0003] The existing grinding disc is generally a metal disc, which is hard and cannot be embedded with abrasives. Generally, a soft pad is attached to the surface of the grinding disc. The soft pad is soft and easy to embed the abrasives, so as to achieve the interaction between the wafer and the abrasives during the grinding process. However, it is currently very difficult to attach the soft pad to the grinding disc. When attaching, bubbles and wrinkles are easily generated between the two. These bubbles and wrinkles will cause uneven distribution of polishing liquid or grinding liquid on the surface of the wafer, resulting in damage to the wafer surface, or even wafer breakage, reducing the wafer processing yield. Summary of the invention

[0004] In view of this, the present application provides a processing pad assembly for a wafer polishing device and a polishing method based thereon, and the scheme of the processing pad assembly is as follows:

[0005] A processing pad assembly for a wafer grinding device, wherein the grinding device has an upper grinding disc and a lower grinding disc that can rotate relatively, and wherein the processing pad assembly comprises:

[0006] The first processing pad and the second processing pad are bonded and fixed by a release adhesive layer;

[0007] Among them, when polishing the wafer, the first processing pad is used to bond and fix to the upper polishing disk, and the second processing pad is used to bond and fix to the lower polishing disk. After removing the release adhesive layer, the wafer is placed between the first processing pad and the second processing pad for polishing.

[0008] Preferably, the first processing pad comprises: a first functional layer for grinding the wafer, and a first adhesive layer bonded and fixed to the first functional layer;

[0009] The second processing pad comprises: a second functional layer for grinding the wafer, and a second adhesive layer bonded and fixed to the second functional layer;

[0010] The first functional layer and the second functional layer are bonded and fixed by the release adhesive layer. When the wafer is polished, the first adhesive layer is used to bond and fix the first functional layer to the upper polishing disc, and the second adhesive layer is used to bond and fix the second functional layer to the lower polishing disc.

[0011] Preferably, a removable first protective layer is adhered to the surface of the first adhesive layer facing away from the first functional layer;

[0012] A removable second protective layer is adhered to the surface of the second adhesive layer facing away from the second functional layer;

[0013] When the wafer is polished, the first protective layer is removed so that the first functional layer is bonded and fixed to the upper polishing disc through the first adhesive layer, and the second protective layer is removed so that the second functional layer is bonded and fixed to the lower polishing disc through the second adhesive layer.

[0014] Preferably, the first protective layer and the second protective layer both include a base layer and an isolation layer;

[0015] In the same protective layer, the base layer is located on a side of the isolation layer facing the release adhesive layer.

[0016] Preferably, the base layer comprises a laminate of one or more of a white paper layer, a yellow paper layer, a kraft paper layer, a glassine paper layer and a cloth layer;

[0017] The isolation layer is a laminate of one or more of a polytetrafluoroethylene layer, a polyolefin layer, a polycarbonate layer, a polyamide layer, a polyacrylonitrile layer and a polyester layer;

[0018] The thickness of the isolation layer is 0.1 mm-0.5 mm.

[0019] Preferably, a surface of one side where the first functional layer is bonded and fixed to the release adhesive layer has a protrusion;

[0020] A surface of one side where the second functional layer is bonded and fixed to the release adhesive layer has a protrusion.

[0021] Preferably, the first functional layer and the second functional layer both include at least one of the following modes:

[0022] The first functional layer and the second functional layer are both laminated layers of one or more of a polyurethane layer and a non-woven fabric layer;

[0023] The protrusions of the first functional layer and the protrusions of the second functional layer both include at least one of a circular shape and a spiral shape;

[0024] The thickness of the first functional layer and the second functional layer is 0.2 mm-1 mm.

[0025] Preferably, the release adhesive layer is a water-soluble glue layer and / or the thickness of the release adhesive layer is 0.1 mm-1 mm.

[0026] The technical solution of the present application also provides a grinding method based on the processing pad assembly, and the grinding method comprises:

[0027] Placing the processing pad assembly horizontally between the upper grinding disc and the lower grinding disc;

[0028] Bonding and fixing the upper grinding disc to the first processing pad;

[0029] Bonding and fixing the lower grinding disc and the second processing pad;

[0030] The first processing pad is separated from the second processing pad by relative movement of the upper grinding disc and the lower grinding disc in the vertical direction;

[0031] After the upper grinding disc and the lower grinding disc are separated from each other, cleaning and removing the release adhesive layer adhered to the surfaces of the first processing pad and the second processing pad;

[0032] The wafer is placed between the first processing pad and the second processing pad, and the wafer is polished based on the relative rotation of the upper polishing disc and the lower polishing disc.

[0033] Preferably, the method further comprises:

[0034] Abrasives are added between the wafer and the first functional layer and between the wafer and the second functional layer.

[0035] Preferably, the upper grinding disc has a feeding hole penetrating the upper grinding disc, and the method of adding the abrasive comprises:

[0036] After the release adhesive layer is cleaned and removed, a through hole is formed at a position of the first processing pad corresponding to the feeding hole based on the feeding hole;

[0037] After the wafer is placed between the first processing pad and the second processing pad, abrasive is added based on the feeding hole and the through hole.

[0038] Preferably, the first processing pad comprises: a first functional layer for grinding the wafer; a first adhesive layer bonded and fixed to the first functional layer; the second processing pad comprises: a second functional layer for grinding the wafer; a second adhesive layer bonded and fixed to the second functional layer; the first adhesive layer is used to bond and fix the first functional layer to the upper grinding disc, and the second adhesive layer is used to bond and fix the second functional layer to the lower grinding disc;

[0039] Wherein, the adhesive force of the first adhesive layer and the adhesive force of the second adhesive layer are both greater than the adhesive force of the release adhesive layer.

[0040] From the above description, it can be known that the technical solution of the present application provides a processing pad assembly for a wafer polishing device, comprising a first processing pad, a second processing pad and a release adhesive layer, wherein the first processing pad and the second processing pad are bonded and fixed by the release adhesive layer, wherein when the wafer is polished, the first processing pad is used to be bonded and fixed to the upper polishing disk, and the second processing pad is used to be bonded and fixed to the lower polishing disk, after removing the release adhesive layer, the wafer is placed between the first processing pad and the second processing pad for polishing, and a front downward pressure pasting method is adopted when the first processing pad and the upper polishing disk are bonded and fixed, and when the second processing pad and the lower polishing disk are bonded and fixed, a front downward pressure pasting method is adopted, by using such a processing pad, the occurrence rate of bubbles and wrinkles of the processing pad during the pasting process can be greatly reduced, and the flatness and stability of the patch of the double-sided processing equipment can be improved, thereby effectively reducing the damage to the wafer surface, reducing the breakage rate of the double-sided processing of the wafer, and improving the double-sided processing yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0042] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0043] Figure 1 A schematic structural diagram of a processing pad assembly provided in an embodiment of the present application;

[0044] Figure 2 A schematic diagram of the structure of a first processing pad in a processing pad assembly provided in an embodiment of the present application;

[0045] Figure 3 A schematic diagram of the structure of a second processing pad in a processing pad assembly provided in an embodiment of the present application;

[0046] Figure 4 A schematic structural diagram of another processing pad assembly provided in an embodiment of the present application;

[0047] Figure 5 A schematic structural diagram of another processing pad assembly provided in an embodiment of the present application;

[0048] Figure 6 A schematic diagram of the structure of the first protective layer and the second protective layer provided in an embodiment of the present application;

[0049] Figure 7 A top view of a functional layer is provided for an embodiment of the present application;

[0050] Figure 8 It is a flow chart of a grinding method of a processing pad assembly according to an embodiment of the present application;

[0051] Fig. 9 It is a schematic diagram of the structure of a grinding device based on the processing pad assembly described in an embodiment of the present application. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the embodiments in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0053] Among the third-generation semiconductor materials, silicon carbide has the characteristics of large bandgap width, high breakdown electric field, high saturated electron drift velocity, and high thermal conductivity. It is suitable for the preparation of high-voltage and high-frequency power devices. It is an ideal material for emerging fields such as electric vehicles, 5G base stations, and satellites.

[0054] Silicon carbide wafers are an important foundation for device manufacturing. The quality and precision of their surface processing directly affect the quality of epitaxial films and the performance of their devices. Therefore, in their applications, the wafer surface is required to be ultra-smooth, defect-free, and damage-free, with a surface roughness value below the nanometer level, and polishing is the main means of wafer surface finishing. Grinding discs are generally metal discs with a hard material that cannot be embedded with abrasives, so a polishing pad is attached to the surface of the polishing disc. The polishing pad is made of a soft material to facilitate the embedding of abrasives. In double-sided polishing equipment, the diameter of the polishing pad used is 1300mm. The existing polishing pad and the polishing disc are attached separately, using a method of pressing while attaching the cloth. The process will cause deformation of the processing pad, resulting in the bonding area of ​​the final standing polishing pad being larger than the disc area, resulting in wrinkles and a long bonding time.

[0055] In order to solve the above problems, the present application provides a processing pad assembly for a wafer polishing equipment and a polishing method based on the processing pad assembly. In the processing pad assembly, the first processing pad and the second processing pad are bonded by a release adhesive layer, and the processing pad assembly is placed between an upper polishing disc and a lower polishing disc. After removing the first protective layer, the bonding and fixation between the upper polishing disc and the first processing pad is performed by a front-down pressure pasting method. After the first processing pad and the upper polishing disc are pasted and fixed, the processing pad assembly as a whole rises vertically upward with the upper polishing disc, and the second protective layer is removed. The second processing pad is pasted by the front-up pressure of the lower polishing disc. By this front-down pressure and front-up pressure pasting method, the generation of bubbles and wrinkles during the pasting process is reduced.

[0056] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0057] refer to Figure 1 , Figure 1 A schematic diagram of the structure of a processing pad assembly provided in an embodiment of the present application, wherein the processing pad assembly is used for a grinding device, and the grinding device can be as follows Fig. 9 As shown, there are an upper grinding disc 7 and a lower grinding disc 8 that can rotate relatively, and the processing pad assembly described in the first embodiment of the present application includes:

[0058] The first processing pad 1 and the second processing pad 2 are bonded and fixed by the release adhesive layer 3;

[0059] Among them, when polishing the chip, the first processing pad 1 is used to bond and fix with the upper polishing disk 7, and the second processing pad 2 is used to bond and fix with the lower polishing disk 8. After removing the release adhesive layer 3, the chip is placed between the first processing pad 1 and the second processing pad 2 for polishing.

[0060] In the processing pad assembly provided in the embodiment of the present application, the first processing pad 1 and the second processing pad 2 are bonded and fixed by the release adhesive layer 3, the first processing pad 1 is bonded and fixed to the upper grinding disk 7, and the second processing pad 2 is bonded and fixed to the lower grinding disk 8. Before grinding, the first processing pad 1 and the second processing pad 2 need to be separated, and the bonding force of the release adhesive layer 3 needs to be smaller than the bonding force between the first processing pad 1 and the upper grinding disk 7 and the bonding force between the second processing pad 2 and the lower grinding disk 8. Before grinding, the release adhesive layer 3 bonded to the surface of the first processing pad 1 and the second processing pad 2 needs to be cleaned, and then the chip is placed between the first processing pad 1 and the second processing pad 2 for grinding.

[0061] refer to Figure 2 , Figure 2This is a schematic structural diagram of the first processing pad in the processing pad assembly provided in an embodiment of the present application. The first processing pad 1 includes: a first functional layer 11 for polishing the wafer, and a first backing layer 12 bonded and fixed to the first functional layer 11.

[0062] refer to Figure 3 , Figure 3 This is a schematic structural diagram of the second processing pad in the processing pad assembly provided in an embodiment of the present application, wherein the second processing pad 2 comprises: a second functional layer 21 for polishing the wafer, and a second adhesive layer 22 bonded and fixed to the second functional layer.

[0063] refer to Figure 4 , Figure 4 A schematic structural diagram of another processing pad assembly provided in an embodiment of the present application, wherein the first functional layer 11 and the second functional layer 21 are bonded and fixed by the release adhesive layer 3, and when the wafer is polished, the first adhesive layer 12 is used to bond and fix the first functional layer 11 to the upper polishing disk 7, and the second adhesive layer 22 bonds and fixes the second functional layer 21 to the lower polishing disk 8.

[0064] In the embodiment of the present application, the first adhesive layer 12 is attached to the first functional layer 11 by spin coating, and the second adhesive layer 22 is also attached to the second functional layer 21 by spin coating. The first adhesive layer 12 and the second adhesive layer 22 are both epoxy resin layers with a thickness of 0.2 mm.

[0065] The first processing pad 1 includes the first adhesive layer 12 and the first functional layer 11, and the second processing pad 2 includes the second adhesive layer 22 and the second functional layer 21, and the wafer is placed between the first functional layer 11 and the second functional layer 21. The first adhesive layer 12 is used to bond and fix the first functional layer 11 to the upper grinding disc 7, and the second adhesive layer 22 is used to bond and fix the second functional layer to the lower grinding disc 8. Before grinding, the first functional layer 11 and the second functional layer 12 are bonded and fixed by the release adhesive layer 3. During grinding, the first adhesive layer 12 is bonded to the upper grinding disc 7, and the second adhesive layer 22 is bonded to the lower grinding disc 8. Among them, the bonding force of the release adhesive layer 3 must be smaller than the bonding force between the first adhesive layer 12 and the upper grinding disc 7 and the bonding force between the second adhesive layer 22 and the lower grinding disc 8. If the bonding force of the release adhesive layer 3 is greater than the bonding force between the first adhesive layer 12 and the upper grinding disk 7 or the bonding force between the second adhesive layer 22 and the lower grinding disk 8, it will result in that when the upper grinding disk 7 and the lower grinding disk 8 are relatively vertically separated, the first functional layer 11 and the second functional layer 21 cannot be separated, thereby making it impossible to grind the chip.

[0066] refer to Figure 5 , Figure 5 A structural diagram of another processing pad assembly provided in an embodiment of the present application is shown in FIG. Figure 5 As shown, a removable first protective layer 13 is attached to the surface of the first adhesive layer 12 facing away from the first functional layer 11 , and a removable second protective layer 23 is attached to the surface of the second adhesive layer 22 facing away from the second functional layer 21 .

[0067] When the chip is polished, the first protective layer 13 is removed so that the first functional layer 11 is bonded and fixed to the upper polishing disk 7 through the first adhesive layer 12, and the second protective layer 23 is removed so that the second functional layer 21 is bonded and fixed to the lower polishing disk 8 through the second adhesive layer 22.

[0068] like Figure 5 As shown, the first protective layer 13 is provided on the surface of the first adhesive layer 12 away from the first functional layer 11. Before the first adhesive layer 12 is bonded and fixed to the upper grinding disc, the first protective layer 13 protects the first adhesive layer 12. When the wafer is polished, the first adhesive layer 12 is bonded and fixed to the upper grinding disc 7 to ensure that the first functional layer 11 is bonded and fixed to the upper grinding disc 7 through the first adhesive layer 12. Therefore, the first protective layer 13 needs to be removed during polishing. The second protective layer 23 is provided on the surface of the second adhesive layer 22 away from the second functional layer 21. Before the second adhesive layer 22 is bonded and fixed to the lower grinding disc 8, the second protective layer 23 protects the second adhesive layer 22. When the wafer is polished, the second adhesive layer 22 is bonded and fixed to the lower grinding disc 8 to ensure that the second functional layer 21 is bonded and fixed to the lower grinding disc 8 through the second adhesive layer 22. Therefore, the second protective layer 23 needs to be removed during polishing.

[0069] refer to Figure 6 , Figure 6 The schematic diagram of the structure of the first protective layer and the second protective layer provided in the embodiment of the present application, the upper figure is a schematic diagram of the structure of the first protective layer 13, and the lower figure is a schematic diagram of the structure of the second protective layer 23, based on Figure 6 It can be seen that both the first protective layer 13 and the second protective layer 23 include a base layer 4 and an isolation layer 5 .

[0070] In the same protective layer, the base layer 4 is located on the side of the isolation layer 5 facing the release adhesive layer 3 .

[0071] As described above, in the same protective layer, the base layer 4 is located on the side of the isolation layer 5 facing the release adhesive layer 3, and the base layer 4 of the first protective layer 13 is bonded to the first adhesive layer 12, and the base layer 4 of the second protective layer 23 is bonded to the second adhesive layer 22.

[0072] The base layer 4 comprises a laminate of one or more of a white paper layer, a yellow paper layer, a kraft paper layer, a glassine paper layer and a cloth layer.

[0073] The isolation layer 5 is a laminate of one or more of a polytetrafluoroethylene layer, a polyolefin layer, a polycarbonate layer, a polyamide layer, a polyacrylonitrile layer and a polyester layer.

[0074] The thickness of the isolation layer is 0.1 mm-0.5 mm.

[0075] The base layer 4 can be prepared by at least one of spin coating, spraying and pasting on a stack of one or more of the white paper layer, yellow paper layer, kraft paper layer, glassine paper layer and cloth layer to obtain a stack of one or more of the polytetrafluoroethylene layer, polyolefin layer, polycarbonate layer, polyamide layer, polyacrylonitrile layer and polyester layer included in the isolation layer 5.

[0076] The first functional layer 11 has a protrusion on one side of the surface where it is bonded and fixed to the release adhesive layer 3;

[0077] The second functional layer 21 has a protrusion on one side of the surface where it is bonded and fixed to the release adhesive layer 3 .

[0078] The first functional layer 11 and the second functional layer 21 are both used to polish the wafer. If the first functional layer and the second functional layer are used to polish one side of the wafer and a smooth surface, no polishing effect can be produced. Therefore, the first functional layer 11 and the second functional layer 12 are used to polish one side of the wafer and both have protrusions. The protrusion of the first functional layer 11 is located on the side where the first functional layer 11 is bonded to the release adhesive layer 3, and the protrusion of the second functional layer 21 is located on the side where the second functional layer 21 is bonded to the release adhesive layer 3. Before polishing the wafer, the release adhesive layer 3 is removed, the wafer is placed between the first functional layer 11 and the second functional layer 21, abrasives are added, and the wafer is polished using the protrusions of the first functional layer 11 and the second functional layer 21.

[0079] The first functional layer 11 and the second functional layer 21 include at least one of the following modes:

[0080] The first functional layer 11 and the second functional layer 21 are both laminated layers of one or more of a polyurethane layer and a non-woven fabric layer;

[0081] refer to Figure 7 , Figure 7 FIG. 1 is a top view of a functional layer provided in an embodiment of the present application. The protrusions 6 of the first functional layer 11 and the protrusions 6 of the second functional layer 21 can be as shown in FIG. Figure 7 As shown, it includes at least one of a circular shape and a spiral shape. The first functional layer 11 and the second functional layer 21 can be Figure 7 The circle shown in the middle left picture, or Figure 7 The spiral line shown in the middle right picture. It should be noted that Figure 7 The two methods only show that the first functional layer and the second functional layer only include one protrusion structure. Obviously, the same functional layer can also include a variety of different protrusion structures.

[0082] The thickness of the first functional layer 11 and the second functional layer 21 is 0.2 mm-1 mm.

[0083] The first functional layer 11 and the second functional layer 21 can be a laminate of polyurethane layers or a laminate of polyurethane layers and non-woven fabric layers. The thickness range of the first functional layer 11 and the second functional layer 21 is 0.2 mm-1 mm, but the thickness is preferably 0.6 mm. The protrusions 6 of the first functional layer 11 and the second functional layer 21 can be different, but both the first functional layer 11 and the second functional layer 21 must have protrusions 6. The shape of the protrusions 6 of the first functional layer 11 and the second functional layer 21 can be at least one of circular or spiral.

[0084] The release adhesive layer 3 is a water-soluble glue layer and / or the thickness of the release adhesive layer 3 is 0.1 mm-1 mm.

[0085] The release adhesive layer 3 is a water-soluble glue layer, preferably a polyvinyl acetate layer, and the thickness of the release adhesive layer 3 is in the range of 0.1 mm to 1 mm. The first functional layer 11 and the second functional layer 21 are bonded through the release adhesive layer 3, and the bonding force of the release adhesive layer 3 is smaller than the bonding force between the first back adhesive layer 12 and the upper grinding disk 7 and the bonding force between the second back adhesive layer 22 and the lower grinding disk 8.

[0086] Based on the processing pad assembly described in the above embodiment, another embodiment of the present application provides a wafer polishing method based on the processing pad assembly of the above embodiment as follows:

[0087] refer to Figure 8 , Figure 8 Flow chart of a grinding method of a processing pad assembly according to an embodiment of the present application. The grinding method of a processing pad assembly according to an embodiment of the present application includes:

[0088] Step S11: placing the processing pad assembly horizontally between the upper grinding disc 7 and the lower grinding disc 8 .

[0089] Step S12: bonding and fixing the upper grinding disc 7 to the first processing pad 1 .

[0090] Step S13: bonding and fixing the lower grinding disc 8 and the second processing pad 2 .

[0091] Step S14: The first processing pad 1 is separated from the second processing pad 2 by relative movement of the upper grinding disc 7 and the lower grinding disc 8 in the vertical direction.

[0092] Step S15: After the upper grinding disc 7 and the lower grinding disc 8 are separated from each other, the release adhesive layer 3 adhered to the surfaces of the first processing pad 1 and the second processing pad 2 is cleaned and removed.

[0093] Step S16: placing the wafer between the first processing pad 1 and the second processing pad 2, and grinding the wafer based on the relative rotation of the upper grinding disc 7 and the lower grinding disc 8.

[0094] refer to Fig. 9 , Fig. 9 This is a schematic diagram of the structure of a grinding device based on the processing pad assembly described in the embodiment of the present application, wherein the grinding device includes: a first rotating device 9, an upper grinding disc 7, a first processing pad 1, a release adhesive layer 3, a second processing pad 2, a lower grinding disc 8, and a second rotating device 10. The first rotating device 9 is used to drive the rotation and movement of the upper grinding disc 7, and the second rotating device 10 is used to drive the rotation and movement of the lower grinding disc 8. When the grinding device is pasting the processing pad assembly, the processing pad assembly is horizontally placed on the lower grinding disc 8. The first rotating device 9 drives the upper grinding disc 7 to press the processing pad assembly downward, so that the upper grinding disc 7 is pasted and fixed to the first processing pad 1. The second rotating device 10 drives the lower grinding disc 8 to press vertically toward the upper grinding disc 7, so that the lower grinding disc 8 is pasted and fixed to the second processing pad 2. The upper grinding disc 7 and the lower grinding disc 8 move relative to each other in the vertical direction, so that the first processing pad 1 is separated from the second processing pad 2. The release adhesive layer 3 is only used to bond and fix the first processing pad 1. Processing pad 1 and second processing pad 2, so after the first processing pad 1 and the second processing pad 2 are separated, the release adhesive layer 3 bonded to the surface of the first processing pad 1 and the second processing pad 2 is cleaned, and then the chip is placed between the upper grinding disc 7 and the lower grinding disc 8 for grinding. In this method, the upper grinding disc 7 and the first processing pad 1 and the lower grinding disc 8 and the second processing pad 2 are both pasted by vertical pressing. This method can effectively reduce the bubbles and wrinkles formed between the grinding disc and the processing pad during pasting, thereby effectively reducing the damage to the chip surface, reducing the double-sided processing breakage rate of the chip, and improving the double-sided processing yield.

[0095] The grinding method of the processing pad assembly according to the embodiment of the present application also includes:

[0096] Abrasives are added between the wafer and the first functional layer 11 and between the wafer and the second functional layer 21 .

[0097] In wafer grinding, adding abrasive is also a necessary step. Abrasive is the main grinding medium used to grind the wafer surface. The selection of abrasive is also very important for wafer grinding. In this embodiment, the abrasive can be one of diamond powder, aluminum oxide powder, silicon carbide powder, and silicon dioxide powder.

[0098] The upper grinding disc 7 has a feeding hole penetrating the upper grinding disc 7, and the method of adding the abrasive includes:

[0099] After the release adhesive layer 3 is cleaned and removed, a through hole is formed at a position of the first processing pad 1 corresponding to the feeding hole based on the feeding hole;

[0100] After the wafer is placed between the first processing pad 1 and the second processing pad 2 , abrasive is added based on the feeding hole and the through hole.

[0101] The abrasive is added into the processing pad through the feeding hole that penetrates the upper grinding disk 7. Since there is no through hole for adding abrasive on the first processing pad 1, a through hole needs to be formed at a position corresponding to the filling hole on the first processing pad 1 after cleaning and removing the release adhesive layer 3. The through hole is obtained by punching the first processing pad 1 with a puncher. After the through hole is punched and the chip is placed, abrasive is added based on the feeding hole and the through hole to start grinding the chip.

[0102] The first processing pad 1 includes: a first functional layer 11 for grinding the wafer; a first adhesive layer 12 bonded and fixed to the first functional layer 11; the second processing pad 2 includes: a second functional layer 21 for grinding the wafer; a second adhesive layer 22 bonded and fixed to the second functional layer 21; the first adhesive layer 12 is used to bond and fix the first functional layer 11 to the upper grinding disc 7, and the second adhesive layer 22 bonds and fixes the second functional layer 21 to the lower grinding disc 8;

[0103] The adhesive force of the first adhesive layer 12 and the adhesive force of the second adhesive layer 22 are both greater than the adhesive force of the release adhesive layer 3 .

[0104] The first functional layer 11 is bonded and fixed to the upper grinding disk 7 through the first back adhesive layer 12. If the bonding force of the first back adhesive layer 12 is less than or equal to the bonding force of the release adhesive layer 3, the first functional layer 11 cannot be separated from the release adhesive layer 3, resulting in an inability to place a chip for grinding. The second functional layer 21 is bonded and fixed to the lower grinding disk 8 through the second back adhesive layer 22. If the bonding force of the second back adhesive layer 22 is less than or equal to the bonding force of the release adhesive layer 3, the second functional layer 21 cannot be separated from the release adhesive layer 3, resulting in an inability to place a chip for grinding.

[0105] In this specification, each embodiment is described in a progressive, parallel, or progressive and parallel manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the method disclosed in the embodiment, since it corresponds to the components disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0106] It should be noted that in the description of the present application, it should be understood that the description of the drawings and embodiments is illustrative rather than restrictive. The same drawings throughout the embodiments of the specification mark the same structure. In addition, for the sake of understanding and ease of description, the drawings may exaggerate the thickness of some layers, films, panels, regions, etc. It is also understood that when an element such as a layer, film, region or substrate is referred to as "on" another element, the element may be directly on the other element or there may be an intermediate element. In addition, "on" refers to positioning an element on or below another element, but does not essentially mean positioning on the upper side of another element according to the direction of gravity.

[0107] The terms "upper", "lower", "top", "bottom", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. When a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time.

[0108] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such components. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the presence of other identical elements in the components including the above elements.

[0109] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A processing pad assembly for a wafer grinding device, wherein the grinding device has an upper grinding disc and a lower grinding disc that can rotate relative to each other, characterized in that: The processing pad assembly comprises: The first processing pad and the second processing pad are bonded and fixed by a release adhesive layer; Wherein, when grinding the wafer, the first processing pad is used to bond and fix with the upper grinding disc, and the second processing pad is used to bond and fix with the lower grinding disc, and after removing the release adhesive layer, the wafer is placed between the first processing pad and the second processing pad for grinding; The first processing pad comprises: a first functional layer for grinding the wafer, and a first adhesive layer bonded and fixed to the first functional layer; the second processing pad comprises: a second functional layer for grinding the wafer, and a second adhesive layer bonded and fixed to the second functional layer; Among them, the bonding force of the release adhesive layer is smaller than the bonding force between the first back adhesive layer and the upper grinding disk and the bonding force between the second back adhesive layer and the lower grinding disk; the first functional layer and the second functional layer are bonded and fixed by the release adhesive layer. When the wafer is polished, the first back adhesive layer is used to bond and fix the first functional layer to the upper grinding disk. After the second back adhesive layer bonds and fixes the second functional layer to the lower grinding disk, the first processing pad and the second processing pad are separated by relative movement of the upper grinding disk and the lower grinding disk in the vertical direction. After cleaning and removing the release adhesive layer, a through hole is formed at the position of the first processing pad corresponding to the feeding hole based on the feeding hole that penetrates the upper grinding disk.

2. The processing pad assembly according to claim 1, characterized in that A removable first protective layer is adhered to the surface of the first adhesive layer facing away from the first functional layer; A removable second protective layer is adhered to the surface of the second adhesive layer facing away from the second functional layer; When the wafer is polished, the first protective layer is removed so that the first functional layer is bonded and fixed to the upper polishing disc through the first adhesive layer, and the second protective layer is removed so that the second functional layer is bonded and fixed to the lower polishing disc through the second adhesive layer.

3. The processing pad assembly according to claim 2, characterized in that The first protective layer and the second protective layer both include a base layer and an isolation layer; In the same protective layer, the base layer is located on a side of the isolation layer facing the release adhesive layer.

4. The processing pad assembly according to claim 3, characterized in that The base layer comprises a laminate of one or more of a white paper layer, a yellow paper layer, a kraft paper layer, a glassine paper layer and a cloth layer; The isolation layer is a laminate of one or more of a polytetrafluoroethylene layer, a polyolefin layer, a polycarbonate layer, a polyamide layer, a polyacrylonitrile layer and a polyester layer; The thickness of the isolation layer is 0.1 mm-0.5 mm.

5. The processing pad assembly according to claim 1, characterized in that The first functional layer has a protrusion on one side of the surface where it is bonded and fixed to the release adhesive layer; A surface of one side where the second functional layer is bonded and fixed to the release adhesive layer has a protrusion.

6. The processing pad assembly according to claim 5, characterized in that At least one of the following methods: The first functional layer and the second functional layer are both laminated layers of one or more of a polyurethane layer and a non-woven fabric layer; The protrusions of the first functional layer and the protrusions of the second functional layer both include at least one of a circular shape and a spiral shape; The thickness of the first functional layer and the second functional layer is 0.2 mm-1 mm.

7. The processing pad assembly according to claim 1, characterized in that The release adhesive layer is a water-soluble glue layer and / or the thickness of the release adhesive layer is 0.1 mm-1 mm.

8. A grinding method based on the processing pad assembly according to any one of claims 1 to 7, characterized in that: The polishing method comprises: Placing the processing pad assembly horizontally between the upper grinding disc and the lower grinding disc; Bonding and fixing the upper grinding disc to the first processing pad; Bonding and fixing the lower grinding disc and the second processing pad; The first processing pad is separated from the second processing pad by relative movement of the upper grinding disc and the lower grinding disc in the vertical direction; After the upper grinding disc and the lower grinding disc are separated from each other, cleaning and removing the release adhesive layer adhered to the surfaces of the first processing pad and the second processing pad; Placing the wafer between the first processing pad and the second processing pad, and grinding the wafer based on the relative rotation of the upper grinding disc and the lower grinding disc; The first processing pad comprises: a first functional layer for grinding the wafer; a first adhesive layer bonded and fixed to the first functional layer; the second processing pad comprises: a second functional layer for grinding the wafer; a second adhesive layer bonded and fixed to the second functional layer; the first adhesive layer is used to bond and fix the first functional layer to the upper grinding disc, and the second adhesive layer is used to bond and fix the second functional layer to the lower grinding disc; wherein the bonding force of the first adhesive layer and the bonding force of the second adhesive layer are both greater than the bonding force of the release adhesive layer; Among them, the upper grinding disc has a feeding hole that runs through the upper grinding disc, and the method of adding the abrasive includes: after cleaning and removing the release adhesive layer, based on the feeding hole, forming a through hole in the first processing pad corresponding to the feeding hole position; after placing the chip between the first processing pad and the second processing pad, adding abrasive based on the feeding hole and the through hole.

9. The grinding method according to claim 8, characterized in that: The method further comprises: Abrasives are added between the wafer and the first functional layer and between the wafer and the second functional layer.

Images