A white pad for wafer rough polishing

Abstract

The utility model discloses a white pad for wafer rough polishing belongs to the technical field of polishing pad, a white pad for wafer rough polishing, including polishing pad layer, the upper end of polishing pad layer is provided with fluid storage pad, the upper end sealed coupling of fluid storage pad has base surface layer, the inside of fluid storage pad is provided with integrative fluid flow cavity, and the inside of fluid flow cavity has non - newtonian fluid layer. The utility model solves the problem that the existing wafer grinding pad in actual use process, and the partial buffer invalidation of polishing pad caused by the breakage of micro air bag will affect the continuity work, the non - newtonian fluid layer of the utility model in the grinding process, and the viscosity changes with the real - time change of pressure, shear rate, realizes adaptive buffer, reduces the wafer edge collapse response speed that partial stress concentration leads to, and the action of cooperation grinding particle can reduce partial leakage, and the surface uniformity is promoted.

Description

Technical Field

[0001] This utility model relates to the field of polishing pad technology, specifically a white pad for rough polishing of wafers. Background Technology

[0002] In the manufacturing process of semiconductor wafers, a polishing step is generally combined to planarize and mirror-finish the surface. In this polishing step, after the polishing pad is fixed to the polishing device, the wafer and other components to be polished are pressed against the polishing pad. While the polishing slurry is being supplied, the two slide relative to each other to perform polishing.

[0003] Chinese patent CN218364024U discloses a wafer polishing pad doped with micro-airbags, comprising a lower part and an upper part. The upper part contains multiple micro-airbags distributed unevenly, each with a diameter of 1-3 mm, exhibiting an irregular distribution within the upper part. This patent can buffer micro-vibrations during the polishing process, maintaining the stability of the polishing pad, facilitating heat dissipation, ensuring uniform heating, and guaranteeing the quality of wafer polishing.

[0004] In actual use, damage to the micro-airbags in the wafer polishing pads of the aforementioned patent can cause localized buffer failure of the polishing pads, affecting continuous operation. Utility Model Content

[0005] The purpose of this invention is to provide a white pad for rough polishing of wafers, which solves the problem mentioned in the background art that damage to the micro-airbags in the wafer polishing pad during actual use can lead to local buffer failure of the polishing pad and affect continuous operation.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a white pad for rough polishing of wafers, comprising a polishing pad layer, a fluid storage pad disposed at the upper end of the polishing pad layer, a base layer sealed to the upper end of the fluid storage pad, an integrally formed fluid flow cavity disposed inside the fluid storage pad, and a non-Newtonian fluid layer stored inside the fluid flow cavity.

[0007] Preferably, the lower end of the base layer is embedded outside the fluid storage pad and between the base layer and the fluid storage pad, and a combined sealing structure of an inner polytetrafluoroethylene anti-corrosion film and an outer silicone elastic film is provided.

[0008] Preferably, a corrosion-resistant encapsulation film is provided between the lower end of the fluid storage pad and the polishing pad layer, and the corrosion-resistant encapsulation film is sealed to the polishing pad layer and the fluid storage pad by laser encapsulation.

[0009] Preferably, the bottom of the fluid storage pad is provided with a plurality of equally spaced grid-like cavities, and the non-Newtonian fluid layer extends into the grid-like cavities and is sealed to the fluid storage pad.

[0010] Preferably, the lower surface of the polishing pad is provided with an integrally formed grinding groove, the position of which corresponds to the position of the mesh cavity.

[0011] Preferably, the fluid storage pad is surrounded by a plurality of nested pad blocks, which are embedded inside the base layer and the polishing pad layer and are sealed to the polishing pad layer and the base layer.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] 1. This utility model introduces a non-Newtonian fluid layer into the fluid flow cavity. During the grinding process, the viscosity of the non-Newtonian fluid layer changes in real time with the pressure and shear rate, achieving adaptive buffering. At low pressure, it is in a liquid state, flexibly adhering to the wafer surface like a micro-airbag. Under high pressure or high frequency vibration, the viscosity rises sharply to a semi-solid state, forming a rigid support, reducing the wafer edge collapse caused by local stress concentration, and the response speed is faster. Combined with the action of the grinding particles, it can reduce local missed polishing and improve surface uniformity.

[0014] 2. The non-Newtonian fluid layer of this utility model can achieve an encapsulated thin-layer structure by using a fluid storage pad with nested pads. After the fluid flow cavity is filled with the non-Newtonian fluid layer and then sealed, the non-Newtonian fluid layer is filled with the grid-like cavity set in the polishing pad layer and then sealed. The non-Newtonian fluid layer in the grid-like cavity forms an airbag-like array. This structure does not require inflation, and the continuity of the non-Newtonian fluid layer can avoid the problem of local failure caused by the single damage of the micro airbag. The fluid storage pad only needs to bear the internal stress of the fluid, which can extend the service life under the same material.

[0015] 3. In the rough polishing stage, the grinding temperature increases. A high-temperature non-Newtonian fluid layer with a shear thickening liquid based on silicone oil can be selected. A grid-like cavity is built into the fluid storage pad. Combined with the grinding grooves at the bottom of the polishing pad layer, heat dissipation is carried out to control the local temperature below 50 degrees Celsius, thereby enabling long-term operation. By applying different pressures to different areas simultaneously by the polishing head, the polishing rate of the grinding grooves and grid-like cavities in the corresponding areas can be adjusted, optimizing the global flatness of the wafer surface. This is beneficial for dealing with complex wafer silicon wafer surface conditions and effectively improving the flatness of the silicon wafer after polishing. Attached Figure Description

[0016] Figure 1 This is an axonometric view of the front view of this utility model;

[0017] Figure 2 This is an axonometric view of the present invention viewed from below;

[0018] Figure 3 This is an axonometric view of the interior of the fluid storage pad of this utility model from the front.

[0019] Figure 4 This is a partial internal structural diagram of the present invention.

[0020] In the diagram: 1. Polishing pad; 2. Base layer; 3. Fluid storage pad; 4. Grinding groove; 5. Fluid flow cavity; 6. Nested pad; 7. Non-Newtonian fluid layer; 8. Mesh cavity. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] To address the issue of uneven localized stress during grinding using existing wafer polishing pads, which negatively impacts work quality, please refer to [link to relevant documentation]. Figure 1 - Figure 4 This embodiment provides the following technical solution:

[0023] A white pad for rough polishing of wafers includes a polishing pad layer 1, a fluid storage pad 3 disposed at the upper end of the polishing pad layer 1, a base layer 2 sealed to the upper end of the fluid storage pad 3, an integrally formed fluid flow cavity 5 disposed inside the fluid storage pad 3, and a non-Newtonian fluid layer 7 stored inside the fluid flow cavity 5. By introducing the non-Newtonian fluid layer 7 into the fluid flow cavity 5, the viscosity of the non-Newtonian fluid layer 7 changes in real time with pressure and shear rate during the polishing process, achieving adaptive buffering. At low pressure, it is in a liquid state and flexibly adheres to the wafer surface like a micro airbag.

[0024] Under high pressure or high frequency vibration, the viscosity rises sharply and becomes semi-solid, forming a rigid support. This reduces the impact of local stress concentration on wafer edge collapse and results in a faster response speed. Combined with the action of abrasive particles, it can reduce local missed polishing and improve surface uniformity.

[0025] The lower surface of the polishing pad 1 is provided with an integrally formed grinding groove 4. The position of the grinding groove 4 corresponds to the position of the mesh cavity 8. A high-temperature resistant non-Newtonian fluid layer 7 based on silicone oil shear thickening fluid can be selected. The mesh cavity 8 is built into the fluid storage pad 3. Together with the grinding groove 4, heat is dissipated at the bottom of the polishing pad 1, and the local temperature is controlled below 50 degrees Celsius, so as to achieve long-term operation. By applying different pressures to different areas simultaneously by the polishing head, the polishing rate of the grinding groove 4 and the mesh cavity 8 in the corresponding areas can be adjusted, optimizing the global flatness of the wafer surface. This is beneficial for dealing with complex wafer silicon wafer surface conditions and effectively improving the flatness of the silicon wafer after polishing.

[0026] Specifically, by introducing a non-Newtonian fluid layer 7 into the fluid flow cavity 5, the viscosity of the non-Newtonian fluid layer 7 changes in real time with pressure and shear rate during the grinding process, achieving adaptive buffering. At low pressure, it is in a liquid state, flexibly adhering to the wafer surface like a micro-airbag. Under high pressure or high frequency vibration, the viscosity rises sharply to a semi-solid state, forming a rigid support, reducing the wafer edge collapse caused by local stress concentration, and the response speed is faster. Combined with the effect of the grinding particles, it can reduce local missed polishing and improve surface uniformity.

[0027] To address the issue that damage to the micro-airbags in existing wafer polishing pads during practical use can lead to localized buffer failure of the polishing pad and disrupt continuous operation, please refer to [link to relevant documentation]. Figure 1 - Figure 4 This embodiment provides the following technical solution:

[0028] The lower end of the base layer 2 is embedded outside the fluid storage pad 3 and is provided with a combined sealing structure of an inner polytetrafluoroethylene anti-corrosion film and an outer silicone elastic film between the fluid storage pad 3 and the base layer 2. A corrosion-resistant encapsulation film is provided between the lower end of the fluid storage pad 3 and the polishing pad layer 1, and the corrosion-resistant encapsulation film is sealed to the polishing pad layer 1 and the fluid storage pad 3 by laser encapsulation.

[0029] The fluid storage pad 3 is surrounded by several nested pads 6. The nested pads 6 are embedded inside the base layer 2 and the polishing pad layer 1 and are sealed to the polishing pad layer 1 and the base layer 2. The non-Newtonian fluid layer 7 can be encapsulated into a thin-layer structure by using the fluid storage pad 3 in conjunction with the nested pads 6. The fluid flow cavity 5 is filled with the non-Newtonian fluid layer 7 and then sealed.

[0030] The bottom of the fluid storage pad 3 is provided with several equally spaced grid-like cavities 8. The non-Newtonian fluid layer 7 extends into the grid-like cavities 8 and is sealed to the fluid storage pad 3. After filling the non-Newtonian fluid layer 7 through the grid-like cavities 8 in the polishing pad layer 1, it is sealed. The non-Newtonian fluid layer 7 in the grid-like cavities 8 forms an airbag-like array. This structure does not require inflation, and the continuity of the non-Newtonian fluid layer 7 can avoid the problem of local failure caused by the single rupture of micro-airbags. The fluid storage pad 3 only needs to bear the internal stress of the fluid, which can extend the service life under the same material.

[0031] Specifically, the non-Newtonian fluid layer 7 can be encapsulated into a thin-layer structure by using a fluid storage pad 3 in conjunction with a nested pad block 6. The fluid flow cavity 5 is filled with the non-Newtonian fluid layer 7 and then sealed. The non-Newtonian fluid layer 7 is filled into the mesh-like cavity 8 set in the polishing pad layer 1 and then sealed. The non-Newtonian fluid layer 7 in the mesh-like cavity 8 forms an airbag-like array. This structure does not require inflation, and the continuity of the non-Newtonian fluid layer 7 can avoid the problem of local failure caused by the single rupture of the micro airbag. The fluid storage pad 3 only needs to bear the internal stress of the fluid, which can extend the service life under the same material.

[0032] Working principle: During use, the base layer 2 is connected to the polishing head to perform rough polishing on the wafer. By introducing a non-Newtonian fluid layer 7 into the fluid flow cavity 5, the viscosity of the non-Newtonian fluid layer 7 changes in real time with pressure and shear rate during the polishing process, achieving adaptive buffering. At low pressure, it is in a liquid state, flexibly adhering to the wafer surface like a micro-airbag. Under high pressure or high-frequency vibration, the viscosity rises sharply to a semi-solid state, forming a rigid support, reducing wafer edge collapse caused by local stress concentration, and resulting in a faster response speed. Combined with the action of the polishing particles, it can reduce local missed polishing and improve surface uniformity. By applying different pressures to different areas simultaneously by the polishing head, the polishing speed of the corresponding polishing grooves 4 and mesh cavities 8 can be adjusted. The efficiency of the non-Newtonian fluid layer 7 is optimized to improve the global flatness of the wafer surface, which is beneficial for dealing with complex wafer surface conditions and effectively improving the flatness of the wafer after polishing. In long-term operation, the non-Newtonian fluid layer 7 can be encapsulated into a thin-layer structure by using the fluid storage pad 3 in combination with the nested pad block 6. The fluid flow cavity 5 is filled with the non-Newtonian fluid layer 7 and then sealed. The non-Newtonian fluid layer 7 is filled with the grid-like cavity 8 set in the polishing pad layer 1 and then sealed. The non-Newtonian fluid layer 7 in the grid-like cavity 8 forms a gasbag-like array. This structure does not require inflation, and the continuity of the non-Newtonian fluid layer 7 can avoid the problem of local failure caused by the single damage of micro-gasbags. The fluid storage pad 3 only needs to bear the internal stress of the fluid, which can extend the service life under the same material.

[0033] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0034] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A white pad for rough polishing of a wafer, comprising a polishing pad layer (1), characterized in that, The upper end of the polishing pad (1) is provided with a fluid storage pad (3), and the upper end of the fluid storage pad (3) is sealed with a base layer (2). The fluid storage pad (3) is provided with an integrally formed fluid flow cavity (5), and the fluid flow cavity (5) contains a non-Newtonian fluid layer (7).

2. The white pad for wafer rough polishing according to claim 1, wherein, The lower end of the base layer (2) is embedded outside the fluid storage pad (3) and is provided with a combined sealing structure of an inner polytetrafluoroethylene anti-corrosion film and an outer silicone elastic film.

3. The white pad for wafer rough polishing according to claim 1, wherein, A corrosion-resistant encapsulation film is provided between the lower end of the fluid storage pad (3) and the polishing pad layer (1), and the corrosion-resistant encapsulation film is sealed to the polishing pad layer (1) and the fluid storage pad (3) by laser encapsulation.

4. The white pad for wafer rough polishing according to claim 1, wherein, The bottom of the fluid storage pad (3) is provided with several equally spaced grid-like cavities (8), and the non-Newtonian fluid layer (7) extends into the grid-like cavities (8) and is sealed to the fluid storage pad (3).

5. The white pad for wafer rough polishing according to claim 4, wherein, The polishing pad (1) has an integrally formed grinding groove (4) on its lower surface, and the position of the grinding groove (4) corresponds to the position of the mesh cavity (8).

6. The white pad for wafer rough polishing according to claim 4, wherein, The fluid storage pad (3) is surrounded by a plurality of nested pad blocks (6), which are embedded inside the base layer (2) and the polishing pad layer (1) and are sealed to the polishing pad layer (1) and the base layer (2).

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