Surface treatment method for chamfered sheet sources

Abstract

The application discloses a chamfered wafer source surface treatment method, and belongs to the technical field of semiconductors. The chamfered wafer source surface treatment method comprises the following steps: S1, bonding a donor substrate and a support substrate to form a first bonding body; S2, beveling the edge of the first bonding body; S3, sleeving a reinforcing ring on the outer peripheral wall of the first bonding body, the reinforcing ring being made of the same material as the donor substrate; S4, making the reinforcing ring flush with the upper surface of the first bonding body; and S5, simultaneously polishing the first bonding body and the reinforcing ring by using a CMP device. In the CMP process, the edge of the wafer is prevented from collapsing, and the bonding quality between wafers is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a surface treatment method for chamfered wafer sources. Background Technology

[0002] Third-generation semiconductor materials currently have a wide range of applications, but generally suffer from low production capacity and high prices. However, a problem exists: during Chemical Mechanical Polishing (CMP), the wafer surface gradually becomes smoother due to mechanical grinding and chemical etching. However, if the chamfers at the edges are right angles, these right-angled areas may directly contact the polishing pad during CMP, leading to over-grinding of the right-angled areas and resulting in rounded corners or edge collapse. This edge collapse phenomenon reduces the bonding quality between wafers.

[0003] Therefore, there is an urgent need to provide a surface treatment method for chamfered wafers to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a surface treatment method for chamfered wafer sources, which avoids edge collapse of the wafer during CMP process and improves the bonding quality between wafers.

[0005] To achieve the above objectives, the following technical solution is provided:

[0006] The surface treatment method for chamfered wafer sources includes the following steps:

[0007] S1. Bond the donor substrate and the support substrate to form a first bond;

[0008] S2. Chamfer the edges of the first bonded body;

[0009] S3. A reinforcing ring is fitted onto the outer peripheral wall of the first bond body, wherein the reinforcing ring is made of the same material as the donor substrate;

[0010] S4. Make the reinforcing ring flush with the upper surface of the first bonded body;

[0011] S5. The first bonding body and the reinforcing ring are polished simultaneously using CMP equipment.

[0012] As an alternative to the surface treatment method for the chamfered wafer source, in step S1, the donor substrate and the support substrate are made of the same material.

[0013] As an alternative to the surface treatment method for the chamfered wafer source, in step S2, the chamfer depth of the right angle is greater than the thickness of the donor substrate.

[0014] As an alternative surface treatment method for the chamfered sheet source, in step S3, an adhesive layer is coated on the outer peripheral wall of the first bond body, and the reinforcing ring is fitted.

[0015] As an optional surface treatment method for the chamfered wafer source, the adhesive layer is cured by high-temperature baking, and the thickness of the adhesive layer is not less than the thickness of the first bond.

[0016] As an alternative surface treatment method for the chamfered sheet source, in step S4, the CMP equipment is used to eliminate the height difference between the reinforcing ring and the upper surface of the first bond body.

[0017] As an optional surface treatment method for the chamfered wafer source, in step S5, after polishing, the polishing fluid residue on the surfaces of the first bond and the reinforcing ring is cleaned and dried.

[0018] As an optional solution to the surface treatment method for the chamfered wafer source, the surface treatment method for the chamfered wafer source further includes the following steps:

[0019] S6. Remove the adhesive layer between the first bond and the reinforcing ring to detach the reinforcing ring from the first bond, and clean and dry the first bond.

[0020] As an optional solution to the surface treatment method for the chamfered wafer source, the surface treatment method for the chamfered wafer source further includes the following steps:

[0021] S7. A damage layer is formed in the donor substrate of the first bond.

[0022] As an optional solution to the surface treatment method for the chamfered wafer source, the surface treatment method for the chamfered wafer source further includes the following steps:

[0023] S8. Take another substrate and bond it to the donor substrate of the first bonding body, so that the donor substrate is separated and transferred along the damaged layer to the other substrate to form a composite substrate;

[0024] The remaining first bonded components proceed to step S2.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The surface treatment method for chamfered wafer sources provided by this invention involves bonding a donor substrate and a support substrate to form a first bond. The superposition of the two wafers enhances the strength of the donor substrate. The edges of the first bond are chamfered to ensure clean, tear-free wafer edges. A reinforcing ring is fitted onto the outer periphery of the first bond. The reinforcing ring is made of the same material as the donor substrate; this homogeneity ensures a consistent polishing rate during CMP processing and prevents the introduction of new impurities. The reinforcing ring is flush with the upper surface of the first bond. CMP equipment is used to simultaneously polish both the first bond and the reinforcing ring. The reinforcing ring resists chemical corrosion and mechanical abrasion during CMP, thus protecting the right-angled shape of the chamfered edges of the first bond. This method prevents edge collapse during CMP processing, ensuring the cleanliness of the wafer edges and the overall quality of the wafer surface. During CMP polishing, edge protection measures ensure full-surface contact between the first bonded wafer surface and the polishing pad. This facilitates the uniform removal of surface damage layers and defects, improving wafer surface processing performance and final product quality. The use of reinforcing rings reduces the likelihood of edge damage to the first bonded wafer during CMP, allowing it to withstand multiple CMP treatments without losing edge integrity, thus enhancing process stability and repeatability. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0028] Figure 1 This is a flowchart of the surface treatment method for the chamfered wafer source in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the process of CMP treatment of the first bond without the use of a reinforcing ring in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the process of CMP treatment performed on the first bond body with a reinforcing ring in an embodiment of the present invention;

[0031] Figure 4 This is a flowchart illustrating the formation of the composite substrate in an embodiment of the present invention.

[0032] Figure label:

[0033] 1. Chamfered edge; 2. Adhesive layer; 3. Reinforcing ring; 4. Collapsed edge defect; 5. Damaged layer; 6. Another substrate. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0038] To prevent edge collapse during CMP and improve the bonding quality between wafers, this embodiment provides a surface treatment method for chamfered wafer sources, which is described below. Figures 1 to 4 The specific content of this embodiment will be described in detail. For example... Figure 2 The image shows the first bond undergoing direct CMP processing, resulting in a collapsed edge defect 4 at the chamfered edge. (See image 4.) Figure 3 The image shows the first bond undergoing CMP treatment directly under the protection of the reinforcing ring 3. No edge collapse defect 4 was generated at the chamfered right-angle edge of the first bond, but the edge collapse defect 4 was generated at the edge of the reinforcing ring 3.

[0039] like Figure 1 Combination Figure 3 As shown, the surface treatment method for the chamfered wafer source in this embodiment includes the following steps: S1, bonding the donor substrate and the support substrate to form a first bond; S2, chamfering the edges of the first bond; S3, fitting a reinforcing ring 3 onto the outer peripheral wall of the first bond, the reinforcing ring 3 being made of the same material as the donor substrate; S4, making the reinforcing ring 3 flush with the upper surface of the first bond; S5, simultaneously polishing the first bond and the reinforcing ring 3 using CMP equipment.

[0040] In summary, the surface treatment method for the chamfered wafer source provided in this embodiment involves bonding a donor substrate and a support substrate to form a first bond. The strength of the donor substrate is increased by stacking the two wafers. The edges of the first bond are chamfered to ensure a clean, tear-free wafer edge. A reinforcing ring 3 is fitted onto the outer peripheral wall of the first bond. The reinforcing ring 3 is made of the same material as the donor substrate; this homogeneity ensures a consistent polishing rate during CMP processing and prevents the introduction of new impurities. The reinforcing ring 3 is flush with the upper surface of the first bond. Both the first bond and the reinforcing ring 3 are polished simultaneously using CMP equipment. The reinforcing ring 3 resists chemical corrosion and mechanical abrasion during CMP, thus protecting the right-angled shape of the chamfered edge of the first bond. This method prevents edge collapse during CMP processing, ensuring the cleanliness of the wafer edge and the overall quality of the wafer surface. During CMP polishing, edge protection measures ensure full-surface contact between the first bonded wafer surface and the polishing pad. This facilitates the uniform removal of surface damage layers and defects, improving the wafer surface processing performance and the quality of the final product. The use of the reinforcing ring 3 reduces the likelihood of edge damage to the first bonded wafer during CMP, allowing it to withstand multiple CMP treatments without losing edge integrity, thus enhancing process stability and repeatability.

[0041] Furthermore, in step S1, the donor substrate and the support substrate are made of the same material and are bonded using homogeneous materials. This helps to ensure that the thermal expansion coefficients of the donor substrate and the support substrate are the same, preventing deformation after high temperature.

[0042] Furthermore, in step S2, the chamfer depth of the right angle is greater than the thickness of the donor substrate. Since sharp edges on the wafer side are prone to breakage and chipping, the chamfer must not have sharp angles to ensure clean, tear-free wafer edges after composite dicing. The chamfer depth exceeding the depth of the top-layer donor substrate facilitates the complete recycling of high-quality material (also known as the donor substrate).

[0043] Furthermore, in step S3, adhesive layer 2 is applied to the outer peripheral wall of the first bonded body using a spin coating method, and reinforcing ring 3 is then fitted. Adhesive layer 2 ensures a stable connection between reinforcing ring 3 and the outer peripheral wall of the first bonded body, making the first bonded body and reinforcing ring 3 a single unit. This facilitates simultaneous grinding of the first bonded body and reinforcing ring 3 during the CMP process. Optionally, adhesive layer 2 can be added to the outer peripheral wall of the first bonded body first, followed by reinforcing ring 3; alternatively, reinforcing ring 3 can be added first, followed by adhesive layer 2. No further restrictions are imposed here.

[0044] Furthermore, the adhesive layer 2 is cured by high-temperature baking, wherein the thickness of the adhesive layer 2 is not less than the thickness of the first bonded body. Since there is a gap between the reinforcing ring 3 and the first bonded body, the gap can be filled with adhesive to form the adhesive layer 2, which can also buffer vibrations from the radial direction.

[0045] Furthermore, in step S4, the thickness of the protective ring is not less than the thickness of the first bond body, and a CMP device is used to eliminate the height difference between the reinforcing ring 3 and the upper surface of the first bond body. The CMP process pre-selects suitable polishing pads and polishing fluids, and adjusts polishing parameters such as pressure, rotation speed, and time. In this embodiment, CMP is used for two polishing processes. The first CMP treatment is used to correct the height difference between the reinforcing ring 3 and the first bond body (also called the wafer source), and the second CMP treatment is used to remove the damaged layer and defects on the surface of the first bond body, correcting the surface roughness and uniformity of the wafer source surface.

[0046] Furthermore, in step S5, after polishing, the polishing fluid residue on the surface of the first bond and the reinforcing ring 3 (sheet source) is cleaned and dried to eliminate the influence of polishing fluid from the CMP equipment.

[0047] Furthermore, the surface treatment method for the chamfered wafer source also includes the following steps: S6, removing the adhesive layer 2 between the first bond and the reinforcing ring 3, wherein sulfuric acid and hydrogen peroxide are used for photoresist removal: when hydrogen peroxide and sulfuric acid are used together, a strongly oxidizing hydrogen sulfate ion (HSO4) is generated. - The oxidizing agents, including hydroxyl radicals (·OH), oxidize the organic matter in the adhesive, converting it into lower molecular weight compounds that are more soluble in water. This removes the cured adhesive layer 2, causing the reinforcing ring 3 to detach from the first bond. The first bond is then thoroughly cleaned to ensure all adhesive residue is removed, and then dried.

[0048] Optionally, the surface treatment method for the chamfered wafer source further includes the following steps: performing a quality inspection on the first bond to confirm that the surface condition of the first bond is good, undamaged, and meets the requirements of subsequent processes.

[0049] Furthermore, such as Figure 4As shown, the surface treatment method for the chamfered wafer source further includes the following step: S7, forming a damage layer 5 in the donor substrate of the first bond. The damage layer 5 can be formed in the donor substrate by ion implantation, but is not limited to that used.

[0050] Furthermore, the surface treatment method for the chamfered wafer source also includes the following steps: S8, taking another substrate 6 and bonding it to the donor substrate of the first bond, so that the donor substrate is separated and transferred along the damaged layer 5 to the other substrate 6 to form a composite substrate; the remaining first bond enters step S2. Through cyclic steps, after multiple bonding and dicing of the donor substrate (high-quality wafer), it is easy to form multiple composite substrates. This allows the high-quality material wafer source to be recycled and reused multiple times, eliminating the need to replace the wafer after each bonding and dicing, which helps to save resources and reduce cost pressure.

[0051] In summary, the technical solution in this embodiment significantly improves the efficiency and product quality of semiconductor manufacturing while reducing production costs by improving material utilization efficiency, enhancing wafer edge and surface quality, reducing deformation risks, and strengthening process stability.

[0052] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A surface treatment method for a chamfered wafer source, characterized in that, Includes the following steps: S1. Bond the donor substrate and the support substrate to form a first bond; S2. Chamfer the edges of the first bonded body; S3. Coat the outer peripheral wall of the first bond body with an adhesive layer (2), and fit the reinforcing ring (3) onto the outer peripheral wall of the first bond body. The reinforcing ring (3) is made of the same material as the donor substrate. S4. Make the reinforcing ring (3) flush with the upper surface of the first bonded body; S5. The first bonding body and the reinforcing ring (3) are polished simultaneously using CMP equipment. S6. Remove the adhesive layer (2) between the first bond and the reinforcing ring (3) to separate the reinforcing ring (3) from the first bond, and clean and dry the first bond.

2. The surface treatment method for chamfered wafers according to claim 1, characterized in that, In step S1, the donor substrate and the support substrate are made of the same material.

3. The surface treatment method for chamfered wafers according to claim 1, characterized in that, In step S2, the chamfer depth of the right angle is greater than the thickness of the donor substrate.

4. The surface treatment method for chamfered wafers according to claim 1, characterized in that, The adhesive layer (2) is cured by high-temperature baking, and the thickness of the adhesive layer (2) is not less than the thickness of the first bond.

5. The surface treatment method for chamfered wafers according to claim 1, characterized in that, In step S4, the CMP device is used to eliminate the height difference between the reinforcing ring (3) and the upper surface of the first bond body.

6. The surface treatment method for chamfered wafers according to claim 1, characterized in that, In step S5, after polishing, the polishing fluid residue on the surfaces of the first bond and the reinforcing ring (3) is cleaned and dried.

7. The surface treatment method for a chamfered wafer source according to any one of claims 1-6, characterized in that, The surface treatment method for the chamfered wafer source further includes the following steps: S7. A damage layer (5) is formed in the donor substrate of the first bonded body.

8. The surface treatment method for chamfered wafers according to claim 7, characterized in that, The surface treatment method for the chamfered wafer source further includes the following steps: S8. Take another substrate (6) and bond it to the donor substrate of the first bonding body, so that the donor substrate is separated and transferred along the damaged layer (5) to the other substrate (6) to form a composite substrate; The remaining first bonded components proceed to step S2.

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