Cmp polishing pad for wafer reconditioning and process for making same

Abstract

The application discloses a kind of CMP polishing pad for wafer regeneration polishing and its preparation process, belong to CMP polishing pad technical field, including substrate layer, reinforcing layer and polishing layer, the upper surface of substrate layer is provided with reinforcing layer, the upper surface of reinforcing layer is provided with polishing layer.The application solves the problem that the support strength of existing CMP polishing pad is low, easy to wear, leading to short service life of CMP polishing pad when using, the reinforcing bottom layer and the reinforcing surface layer are prepared by using polyurethane fiber and polyamide fiber as raw materials, and the support layer is processed in the reinforcing bottom layer, the support member is inflated by inflator, and the reinforcing bottom layer and the reinforcing surface layer are further supported by the air holes arranged on the support strip, the support strength of CMP polishing pad can be improved by setting the reinforcing layer, the wear of CMP polishing pad can be prevented, the wear resistance of CMP polishing pad can be improved, and the service life of CMP polishing pad can be prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the CMP polishing pad technical field, specifically to a CMP polishing pad for wafer regeneration polishing and a preparation process thereof. BACKGROUND

[0002] The CMP polishing pad is mainly used in the fields of semiconductor, sapphire, metal and ceramic, and is composed of polyurethane or a composite material mainly composed of polyurethane. The surface of the polishing pad is micro-convex, directly contacts with the polished piece to produce friction, removes the polishing layer in a mechanical way under the action of centrifugal force, uniformly sprays the polishing liquid to the surface of the polishing pad to remove the polishing layer in a chemical way, and carries out the reaction product out of the polishing pad. The properties of the polishing pad directly affect the surface quality of the polished piece, and are one of the direct factors related to the planarization effect.

[0003] The existing CMP polishing pad has low supporting strength and is easy to wear, resulting in short service life of the CMP polishing pad. SUMMARY

[0004] The present application provides a CMP polishing pad for wafer regeneration polishing and a preparation process thereof, which can improve the supporting strength of the CMP polishing pad, prevent the CMP polishing pad from wearing, improve the wear resistance of the CMP polishing pad, prolong the service life of the CMP polishing pad, and solve the problems in the above background.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0006] A CMP polishing pad for wafer regeneration polishing, comprising a base layer, a reinforcing layer and a polishing layer, the upper surface of the base layer is provided with the reinforcing layer, and the upper surface of the reinforcing layer is provided with the polishing layer, wherein the thickness ratio of the base layer, the reinforcing layer and the polishing layer is 2:3:1.

[0007] Preferably, the base layer takes polyurethane as raw material, the polyurethane raw material is added into an extruder, the polyurethane raw material is stirred, mixed, plasticized and compressed in the extruder, the pre-product is extruded, and the pre-product is repeatedly extruded and extended in a calendering machine to form a calendering product, and the calendering product is processed to form a base layer with uniform thickness.

[0008] Preferably, the reinforcing layer comprises a reinforcing bottom layer and a reinforcing surface layer, the reinforcing bottom layer is arranged on the base layer, and the reinforcing surface layer is arranged on the reinforcing bottom layer, and the reinforcing surface layer is connected with the polishing layer.

[0009] Preferably, the reinforcing layer further comprises a supporting layer, the supporting layer is arranged on the inner side of the reinforcing bottom layer and the reinforcing surface layer, the upper end of the supporting layer is connected with the inner side of the reinforcing surface layer, and the lower end of the supporting layer is connected with the inner side of the reinforcing bottom layer.

[0010] Preferably, the support layer comprises a support and support strips, the support strips are arranged on the support, and the support strips are distributed in a crisscross manner on the support.

[0011] Preferably, the support and the support strips are in communication, and the support strips are provided with air holes for inflating the reinforced bottom layer and the reinforced surface layer.

[0012] Preferably, the support is provided with an interface, the interface penetrates the reinforced bottom layer, and the interface is connected to an inflator.

[0013] Preferably, the polishing layer comprises the following raw materials in mass fraction: 50-70 parts of sub-micron cerium oxide, 2-5 parts of zirconium oxide, 5-10 parts of chromium oxide, 10-15 parts of rare earth, 5-10 parts of silicon dioxide, and the balance of cobalt.

[0014] According to another aspect of the present application, a preparation process of a CMP polishing pad for wafer regeneration polishing is provided, comprising the following steps:

[0015] S1, preparing a base layer:

[0016] The polyurethane raw material is added into an extruder, and the polyurethane raw material is stirred, mixed, plasticized and compacted by the extruder to extrude a pre-product. The pre-product is repeatedly extruded and stretched by a calender to form a calendered product. The calendered product is processed to form a base layer with uniform thickness.

[0017] S2, preparing a reinforcing layer:

[0018] The polyurethane fiber and the polyamide fiber are used as raw materials, and are melted, injected, solidified and formed by a forming machine to form a reinforced bottom layer and a reinforced surface layer.

[0019] Air holes are processed on the support strips, the support strips are processed on the support in a crisscross manner, and the support and the support strips are in communication to form a support layer.

[0020] The support layer is processed in the reinforced bottom layer, and the reinforced surface layer is bonded on the reinforced bottom layer to form a reinforcing layer.

[0021] S3, preparing a polishing layer:

[0022] The sub-micron cerium oxide, the zirconium oxide, the chromium oxide, the rare earth, the silicon dioxide and the cobalt are added into a mixing grinder in proportion, and are fully mixed and ground. After being formed by die molding, a polishing layer is formed.

[0023] S4, preparing a CMP polishing pad:

[0024] The CMP polishing pad is formed by laminating and shaping the base layer, the reinforcing layer and the polishing layer through a laminating machine.

[0025] Compared with the prior art, the CMP polishing pad has the following advantages:

[0026] The CMP polishing pad is prepared by using polyurethane fibers and polyamide fibers as raw materials to prepare the reinforcing bottom layer and the reinforcing surface layer, and the support layer is processed in the reinforcing bottom layer. When the CMP polishing pad is used, the support member is inflated by the inflator, the air is discharged through the air holes arranged on the support strip, and the reinforcing bottom layer and the reinforcing surface layer are further supported. The reinforcing layer can improve the support strength of the CMP polishing pad, prevent the CMP polishing pad from being worn, improve the wear resistance of the CMP polishing pad, and prolong the service life of the CMP polishing pad. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a forward schematic view of the CMP polishing pad for wafer regeneration polishing of the application;

[0028] Figure 2 It is a structural schematic view of the reinforcing layer of the first embodiment of the application;

[0029] Figure 3 It is a structural schematic view of the reinforcing layer of the second embodiment of the application;

[0030] Figure 4 It is an exploded view of the reinforcing layer of the second embodiment of the application;

[0031] Figure 5 It is a downward schematic view of the support layer of the second embodiment of the application;

[0032] Figure 6 It is an upward schematic view of the support layer of the second embodiment of the application.

[0033] In the figure: 1, base layer; 2, reinforcing layer; 21, reinforcing bottom layer; 22, reinforcing surface layer; 23, support layer; 231, support member; 2311, interface; 232, support strip; 2321, air hole; 3, polishing layer. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0035] In order to solve the problem of low supporting strength, easy to wear and short service life of the existing CMP polishing pad during use, please refer to Figures 1-6 The embodiment provides the following technical scheme:

[0036] Embodiment one

[0037] A CMP polishing pad for wafer regeneration polishing comprises a base layer 1, a reinforcing layer 2 and a polishing layer 3, the upper surface of the base layer 1 is provided with the reinforcing layer 2, and the upper surface of the reinforcing layer 2 is provided with the polishing layer 3, wherein the thickness ratio of the base layer 1, the reinforcing layer 2 and the polishing layer 3 is 2:3:1.

[0038] In the embodiment, the base layer 1 is prepared by using polyurethane as raw material, the polyurethane raw material is stirred, mixed, plasticized and compressed in an extruder, a pre-product is extruded, the pre-product is repeatedly extruded and stretched in a calendering machine to form a calendering product, and the calendering product is processed to form the base layer 1 with uniform thickness.

[0039] In the embodiment, the reinforcing layer 2 comprises a reinforcing bottom layer 21 and a reinforcing surface layer 22, the reinforcing bottom layer 21 is arranged on the base layer 1, the reinforcing surface layer 22 is arranged on the reinforcing bottom layer 21, and the reinforcing surface layer 22 is connected with the polishing layer 3.

[0040] It should be noted that the reinforcing bottom layer 21 and the reinforcing surface layer 22 are prepared by using polyurethane fibers and polyamide fibers as raw materials, the polyurethane fibers and the polyamide fibers have good supporting strength, wear resistance and elasticity, therefore, the supporting strength of the CMP polishing pad can be improved by arranging the reinforcing layer 2, the CMP polishing pad can be prevented from being worn, the wear resistance of the CMP polishing pad can be improved, and the service life of the CMP polishing pad can be prolonged.

[0041] In the embodiment, the polishing layer 3 comprises the following raw materials in mass fraction: 50-70 parts of submicron cerium oxide, 2-5 parts of zirconium oxide, 5-10 parts of chromium oxide, 10-15 parts of rare earth, 5-10 parts of silicon dioxide and the balance of cobalt.

[0042] In order to better show the preparation process of the CMP polishing pad for wafer regeneration polishing, the embodiment provides a preparation process of the CMP polishing pad for wafer regeneration polishing according to the above, which comprises the following steps:

[0043] S1, preparing the base layer 1:

[0044] The polyurethane raw material is added into an extruder, the polyurethane raw material is stirred, mixed, plasticized and compressed in the extruder, a pre-product is extruded, the pre-product is repeatedly extruded and stretched in a calendering machine to form a calendering product, and the calendering product is processed to form the base layer 1 with uniform thickness;

[0045] S2, preparing the reinforcing layer 2:

[0046] The polyurethane fiber and the polyamide fiber are used as raw materials, and the reinforcing bottom layer 21 and the reinforcing surface layer 22 are formed by melting, injection, solidification and molding through a molding machine.

[0047] The reinforcing surface layer 22 is bonded to the reinforcing bottom layer 21 to form the reinforcing layer 2.

[0048] S3, preparing the polishing layer 3:

[0049] The sub-micron cerium oxide, zirconium oxide, chromium oxide, rare earth, silicon dioxide and cobalt are added to a mixing grinder in a certain proportion, and are fully mixed and ground. After being molded by a molding machine, the polishing layer 3 is formed.

[0050] S4, preparing the CMP polishing pad:

[0051] The CMP polishing pad is formed by arranging the reinforcing layer 2 on the base layer 1 and arranging the polishing layer 3 on the reinforcing layer 2, and then laminating and shaping the base layer 1, the reinforcing layer 2 and the polishing layer 3 by a laminating machine.

[0052] Example two

[0053] The CMP polishing pad for wafer regeneration polishing comprises a base layer 1, a reinforcing layer 2 and a polishing layer 3. The upper surface of the base layer 1 is provided with the reinforcing layer 2, and the upper surface of the reinforcing layer 2 is provided with the polishing layer 3. The thickness ratio of the base layer 1, the reinforcing layer 2 and the polishing layer 3 is 2:3:1.

[0054] In this embodiment, the base layer 1 uses polyurethane as raw material. The polyurethane raw material is added into an extruder, and is stirred, mixed, plasticized and compacted by the extruder to extrude a pre-product. The pre-product is repeatedly extruded and extended by a calendering machine to form a calendered product. The calendered product is processed to form a base layer 1 with uniform thickness.

[0055] In this embodiment, the reinforcing layer 2 comprises a reinforcing bottom layer 21 and a reinforcing surface layer 22. The reinforcing bottom layer 21 is arranged on the base layer 1, and the reinforcing surface layer 22 is arranged on the reinforcing bottom layer 21. The reinforcing surface layer 22 is connected with the polishing layer 3.

[0056] In this embodiment, the reinforcing layer 2 further comprises a supporting layer 23. The supporting layer 23 is arranged on the inner side of the reinforcing bottom layer 21 and the reinforcing surface layer 22. The upper end of the supporting layer 23 is connected with the inner side of the reinforcing surface layer 22, and the lower end of the supporting layer 23 is connected with the inner side of the reinforcing bottom layer 21.

[0057] In this embodiment, the supporting layer 23 comprises a support 231 and a support strip 232. The support strip 232 is arranged on the support 231, and is distributed on the support 231 in a longitudinal and transverse staggered manner.

[0058] In the embodiment, the support 231 and the support strip 232 are communicated, and the support strip 232 is provided with the air hole 2321 for supporting the reinforced bottom layer 21 and the reinforced surface layer 22.

[0059] In the embodiment, the support 231 is provided with the interface 2311 penetrating the reinforced bottom layer 21, and the interface 2311 is connected with the inflator.

[0060] It should be noted that when the CMP polishing pad is used, the interface 2311 is connected with the inflator, the support 231 is inflated by the inflator, the gas in the support 231 is discharged through the air hole 2321 of the support strip 232, and the reinforced bottom layer 21 and the reinforced surface layer 22 are further supported, so that the support strength of the CMP polishing pad is further improved.

[0061] In the embodiment, the polishing layer 3 comprises the following raw materials in mass fraction: 50-70 parts of sub-micron cerium oxide, 2-5 parts of zirconium oxide, 5-10 parts of chromium oxide, 10-15 parts of rare earth, 5-10 parts of silicon dioxide, and the balance of cobalt.

[0062] In order to better show the preparation process of the CMP polishing pad for wafer regeneration polishing, the embodiment provides a preparation process of the CMP polishing pad for wafer regeneration polishing according to the above, which comprises the following steps:

[0063] S1, preparing the base layer 1:

[0064] The polyurethane raw material is added into the extruder, the polyurethane raw material is stirred, mixed, plasticized and compacted by the extruder, the pre-product is extruded, and the pre-product is repeatedly extruded and stretched by the calender to form a calender product, and the calender product is processed to form the base layer 1 with uniform thickness;

[0065] S2, preparing the reinforcing layer 2:

[0066] The polyurethane fiber and the polyamide fiber are used as raw materials, and are melted, injected, solidified and formed by the forming machine to form the reinforced bottom layer 21 and the reinforced surface layer 22;

[0067] The air hole 2321 is processed on the support strip 232, the support strip 232 is processed on the support 231 in a longitudinal and transverse staggered manner, and the support 231 and the support strip 232 are communicated to form the support layer 23;

[0068] The support layer 23 is processed in the reinforced bottom layer 21, and the reinforced surface layer 22 is bonded on the reinforced bottom layer 21 to form the reinforcing layer 2;

[0069] S3, preparing the polishing layer 3:

[0070] Submicron cerium oxide, zirconium oxide, chromium oxide, rare earth, silicon dioxide and cobalt are added into a mixing grinder in proportion, and are fully mixed and ground. After being molded by a molding machine, the polishing layer 3 is formed.

[0071] S4, preparing the CMP polishing pad:

[0072] The reinforcing layer 2 is arranged on the base layer 1, and the polishing layer 3 is arranged on the reinforcing layer 2. After the base layer 1, the reinforcing layer 2 and the polishing layer 3 are laminated and shaped by a laminating machine, the CMP polishing pad is formed.

[0073] Comparative example

[0074] A CMP polishing pad for wafer regeneration polishing comprises a base layer 1 and a polishing layer 3. The upper surface of the base layer 1 is provided with the polishing layer 3.

[0075] In the embodiment, the base layer 1 is prepared by using polyurethane as raw material. The polyurethane raw material is stirred, mixed, plasticized and compacted in an extruder to extrude a pre-product. The pre-product is repeatedly extruded and extended in a calendering machine to form a calendered product. The calendered product is processed to form the base layer 1 with uniform thickness.

[0076] In the embodiment, the polishing layer 3 comprises the following raw materials in mass fraction: submicron cerium oxide 50-70 parts, zirconium oxide 2-5 parts, chromium oxide 5-10 parts, rare earth 10-15 parts, silicon dioxide 5-10 parts and the balance cobalt.

[0077] Compared with the embodiment one, the reinforcing layer 2 structure is cancelled in the comparative example. The CMP polishing pad is prepared by using the same preparation process as that of the embodiment one, and the preparation step of the reinforcing layer 2 is cancelled accordingly.

[0078] The CMP polishing pads prepared in the embodiment 1-2 and the comparative example are tested for performance. The performance test results of the CMP polishing pads are shown in Table 1.

[0079] Table 1: Performance test results of CMP polishing pad

[0080] Example 1 Example 2 Comparative Example Reinforcement layer / yes / no Yes Yes No Support layer / yes / no No Yes No Support strength / 100% 92.84％ 98.36％ 82.64％ Wear resistance / 100% 93.17％ 98.79％ 82.73％

[0081] As shown in the above table, the CMP polishing pads prepared in the embodiment one to the embodiment two all have good support strength and wear resistance.

[0082] Among them, the embodiment two compared with the embodiment one, it increases the support layer 23 structure, makes the support strength and wear resistance of the CMP polishing pad all improve, explains that increases the support layer 23 structure can improve the support strength and wear resistance of the CMP polishing pad.

[0083] Among them, compared with Example 1, the support strength and wear resistance of the comparative example are both reduced. Since the reinforcing layer 2 structure is not added in the comparative example, the support strength and wear resistance of the CMP polishing pad are both reduced, indicating that the reinforcing layer 2 can improve the support strength and wear resistance of the CMP polishing pad.

[0084] Therefore, the reinforcing bottom layer 21 and the reinforcing surface layer 22 are prepared by using polyurethane fiber and polyamide fiber as raw materials, and the supporting layer 23 is processed in the reinforcing bottom layer 21. When the CMP polishing pad is in use, the air is inflated into the supporting part 231 by the inflator, and discharged through the air holes 2321 set on the support bar 232 to further support the reinforcing bottom layer 21 and the reinforcing surface layer 22. The reinforcing layer 2 set can improve the supporting strength of the CMP polishing pad, prevent the CMP polishing pad from wear, improve the wear resistance of the CMP polishing pad, and extend the service life of the CMP polishing pad.

[0085] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0086] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A CMP polishing pad for wafer regeneration polishing, comprising a base layer (1), a reinforcement layer (2) and a polishing layer (3), characterized in that: A reinforcing layer (2) is provided on the upper surface of the base layer (1), and a polishing layer (3) is provided on the upper surface of the reinforcing layer (2), wherein the thickness ratio of the base layer (1), the reinforcing layer (2) and the polishing layer (3) is 2:3:1; The reinforcing layer (2) comprises a reinforcing bottom layer (21) and a reinforcing surface layer (22), wherein the reinforcing bottom layer (21) is arranged on the base layer (1), and a reinforcing surface layer (22) is arranged on the reinforcing bottom layer (21), and the reinforcing surface layer (22) is connected to the polishing layer (3); The reinforcement layer (2) further comprises a support layer (23), wherein the support layer (23) is arranged on the inner side of the reinforcement bottom layer (21) and the reinforcement surface layer (22), and the upper end of the support layer (23) is connected to the inner side of the reinforcement surface layer (22), and the lower end of the support layer (23) is connected to the inner side of the reinforcement bottom layer (21); The support layer (23) comprises a support member (231) and a support strip (232); the support member (231) is provided with a support strip (232); the support strips (232) are distributed on the support member (231) in a crisscross pattern; the support member (231) and the support strips (232) are connected; and the support strips (232) are provided with air holes (2321); the air holes (2321) are used for inflating and supporting the enhanced bottom layer (21) and the enhanced surface layer (22); the support member (231) is provided with an interface (2311); the interface (2311) passes through the enhanced bottom layer (21), and the interface (2311) is connected to an inflator.

2. The CMP polishing pad for wafer regeneration polishing according to claim 1, characterized in that: The base layer (1) is made of polyurethane as raw material. The polyurethane raw material is added into an extruder, and the polyurethane raw material is stirred, mixed, plasticized and compacted by the extruder to extrude a pre-product. The pre-product is repeatedly extruded and stretched by a calender to form a calendered product. The calendered product is processed to form a base layer (1) with uniform thickness.

3. The CMP polishing pad for wafer regeneration polishing according to claim 1, characterized in that: The polishing layer (3) comprises the following raw materials in parts by mass: 50-70 parts of submicron cerium oxide, 2-5 parts of zirconium oxide, 5-10 parts of chromium oxide, 10-15 parts of rare earth, 5-10 parts of silicon dioxide and the balance of cobalt.

4. A process for preparing a CMP polishing pad for wafer regeneration polishing according to any one of claims 1 to 3, characterized in that: The steps include: S1. Preparation of base layer (1): The polyurethane raw material is added into an extruder, and the polyurethane raw material is stirred, mixed, plasticized and compacted by the extruder to extrude a pre-product, and the pre-product is repeatedly extruded and stretched by a calender to form a calendered product, and the calendered product is processed to form a base layer (1) with uniform thickness; S2. Preparation of reinforcement layer (2): Using polyurethane fiber and polyamide fiber as raw materials, the fibers are melted, injected, solidified, and molded in a molding machine to form a reinforcing bottom layer (21) and a reinforcing surface layer (22); Processing air holes (2321) on the support strips (232), processing the support strips (232) on the support member (231) in a crisscross manner, and connecting the support member (231) and the support strips (232) to form a support layer (23); Processing the support layer (23) into the reinforcing bottom layer (21), and bonding the reinforcing surface layer (22) to the reinforcing bottom layer (21) to form a reinforcing layer (2); S3. Preparation of polishing layer (3): Submicron cerium oxide, zirconium oxide, chromium oxide, rare earth, silicon dioxide and cobalt are added into a mixing grinder in proportion, mixed and ground thoroughly, and then molded to form a polishing layer (3); S4. Preparation of CMP polishing pad: A reinforcement layer (2) is provided on a base layer (1), and a polishing layer (3) is provided on the reinforcement layer (2). The base layer (1), the reinforcement layer (2), and the polishing layer (3) are laminated and shaped by a laminating machine to form a CMP polishing pad.

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