Buffing process method and system for thin wafer

Abstract

The invention belongs to the field of semiconductor manufacturing, and particularly relates to a bumping process method for a thin wafer, which comprises the following steps of: S1, cleaning and activating a bonding surface of a glass slide and a wafer; s2, coating bonding glue on the bonding surface of the glass slide, and then aligning and pressing a wafer and the glass slide coated with the temporary bonding glue to form a rigid composite structure; s3, performing a salient point manufacturing process on the composite structure; s4, laser de-bonding is carried out after the salient points are manufactured; and S5, cleaning the wafer after the de-bonding. According to the method, the wafer and the glass carrier are temporarily bonded, so that stable bonding of the thin wafer of 100-200 microns is realized, the problem of wafer deformation or fragmentation in a traditional method is avoided, and smooth proceeding of a subsequent process is ensured. The technological method is easy to operate, automatic production is easy to achieve, good universality and repeatability are achieved, the method is suitable for machining of various types of ultrathin wafers, and important practical value and application and popularization prospects are achieved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and more particularly to a method and system for a thin wafer bumping process. Background Technology

[0002] With the rapid development of semiconductor technology, chip structures are gradually evolving towards three-dimensionality to meet the demands for high integration, high performance, and low power consumption. As three-dimensional integrated circuit technology advances, chip thickness continues to decrease. However, thin wafers, such as those with a thickness of 100-200 micrometers, have low mechanical strength and are prone to warping. In traditional bump-based manufacturing processes, they struggle to withstand mechanical stress, thermal stress, and liquid surface tension, leading to difficulties in data transfer, high breakage rates, and decreased yield.

[0003] Therefore, there is an urgent need to develop a bumping process method suitable for thin wafers to solve the existing technical problems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to design a bumping process method for temporary bonding and debonding of thin wafers based on a glass substrate, thereby solving the existing technical problems.

[0005] To address the aforementioned technical problems, this invention provides a bumping process for thin wafers, which involves temporarily bonding a glass substrate to the thin wafer, specifically including the following steps: Step S1: Surface treatment: Cleaning and activation treatment of the bonding surfaces of the glass substrate and the wafer; Step S2: Temporary bonding: Apply bonding adhesive to the bonding surface of the glass substrate, then align and press the wafer with the glass substrate coated with temporary bonding adhesive to form a rigid composite structure. Step S3: Bump manufacturing: Perform a bump manufacturing process on the composite structure; Step S4: Laser debonding: Laser debonding is performed after the bump manufacturing is completed; Step S5: Clean the debonded wafer.

[0006] Furthermore, step S1 in this invention specifically includes the following steps: Step S101: Spray deionized water onto the bonding surfaces of the glass substrate and the wafer to completely cover the bonding surfaces; Step S102: Perform hydrophobic treatment on the bonding surface between the glass carrier and the wafer; Step S103: Perform scanning cleaning on the bonding surfaces of the glass carrier and the wafer.

[0007] Furthermore, in this invention, the glass substrate is a borosilicate glass substrate.

[0008] Furthermore, in step S2 of this invention, the thickness of the coated bonding adhesive is 0.5~1.0 μm.

[0009] In a further step of this invention, in step S4, a laser beam is used to irradiate the temporary bonding adhesive layer through the glass substrate, causing the adhesive layer to carbonize or ablate at the interface, thereby achieving non-destructive separation of the wafer from the glass substrate.

[0010] Furthermore, in this invention, the laser wavelength is 355 nm, the single-pulse energy density of the laser is 400~600 mJ / cm², and the scanning interval is 50~70 μm.

[0011] Furthermore, in this invention, a gas gun is used to remove the carbonized adhesive residue and to detect whether the bonding is completely broken.

[0012] In a further step of this invention, in step S5, the debonded wafer is transferred to a rotating platform, and an annular fixing member is used to press onto the non-circuit area of ​​the edge of the wafer for rigid fixation. Subsequently, the wafer surface is cleaned and dried.

[0013] The present invention also provides a thin wafer bumping process system, which employs the aforementioned thin wafer bumping process method, and specifically includes the following modules: Temporary bonding module, used to bond thin wafers and glass substrates into a composite structure using a temporary bonding adhesive layer; A bump manufacturing module is used to perform bump processing on the composite structure; The laser debonding module is used to irradiate a glass substrate with a laser to cause the temporary bonding adhesive layer to fail, thus separating the wafer from the substrate; A cleaning module for rotating and cleaning wafers includes a rotating platform and an annular fixing member, which is used to press against the edge area of ​​the thin wafer for fixation during cleaning.

[0014] The thin wafer bumping process of this invention is based on temporary bonding and debonding of a glass substrate, and has the following technical advantages compared with the prior art: 1. This invention achieves stable bonding of relatively thin wafers of 100-200 micrometers by temporarily bonding the wafer to the glass substrate by coating a layer of bonding adhesive of 0.5-1.0 μm on the glass substrate. This avoids the problems of wafer deformation or breakage in traditional methods and ensures the smooth progress of subsequent processes.

[0015] 2. The present invention employs a method of coating bonding adhesive on a glass substrate, which enables the laser to accurately act on the interface between the photosensitive material and the substrate wafer during the debonding process. This solves the problem of inaccurate laser ablation position in the prior art and significantly improves the effect and efficiency of debonding.

[0016] 3. This invention achieves an efficient debonding process by optimizing the parameters and scanning path of the laser beam, avoiding excessive ablation of the device wafer surface by high-energy-density laser, effectively reducing the residue of carbonized debris, and improving the cleaning effect and the yield of chip devices.

[0017] 4. The present invention uses a combination of a rotating platform and a ring ring for cleaning after debonding, which ensures the integrity and performance of the wafer, meets the requirements of high precision and high reliability, and overcomes the defect of uneven local bonding of wafers in the prior art.

[0018] 5. The process method of the present invention is simple to operate, easy to automate, has good universality and repeatability, and is applicable to various types of ultrathin wafer processing. It has important practical value and promising prospects for widespread application. Attached Figure Description

[0019] The specific embodiments of the present invention will be further explained below with reference to the accompanying drawings.

[0020] Figure 1 This is a flowchart of the thin wafer bumping process of the present invention.

[0021] Figure 2 This is a system diagram of the thin wafer bumping process system of the present invention. Detailed Implementation Example 1

[0022] Combination Figure 1 As shown, the thin wafer bumping process of this embodiment temporarily bonds the glass substrate to the thin wafer, specifically including the following steps: Step S1: Surface treatment: Clean and activate the bonding surfaces of the glass substrate and the wafer.

[0023] In this embodiment, step S1 preferably includes the following steps: Step S101: Spray deionized water onto the bonding surfaces of the glass substrate and the wafer to completely cover the bonding surfaces. Specifically, in this embodiment, the spray pressure is controlled at 0.1~0.5 MPa, and the spray time is 30~60 seconds.

[0024] Step S102: Perform hydrophobic treatment on the bonding surface between the glass carrier and the wafer. Specifically, in this embodiment, the wafer is immersed in a nano-silica solution for 15-30 minutes.

[0025] Step S103: Perform scanning cleaning on the bonding surfaces of the glass substrate and the wafer. Specifically, in this embodiment, the scanning frequency is 10~20 Hz and the scanning distance is 50~100 μm.

[0026] In this embodiment, preferably, the glass slide is a borosilicate glass slide.

[0027] Step S2: Temporary bonding: Apply bonding adhesive to the bonding surface of the glass substrate, then align and press the wafer with the glass substrate coated with temporary bonding adhesive to form a rigid composite structure.

[0028] In this embodiment, preferably, in step S2, the thickness of the bonding adhesive is 0.5~1.0 μm.

[0029] Step S3: Bump manufacturing: Perform a bump manufacturing process on the composite structure.

[0030] Step S4: Laser debonding: Laser debonding is performed after the bump manufacturing is completed.

[0031] In this embodiment, preferably, in step S4, a laser beam is used to irradiate the temporary bonding adhesive layer through the glass substrate, causing the adhesive layer to carbonize or ablate at the interface, thereby achieving non-destructive separation of the wafer and the glass substrate.

[0032] In this embodiment, preferably, the laser wavelength is 355 nm, the single-pulse energy density of the laser is 400~600 mJ / cm², and the scanning spacing is 50~70 μm.

[0033] In this embodiment, preferably, a gas gun is used to remove the carbonized adhesive residue and to check whether the bonding is completely broken. Specifically, in this embodiment, the gas pressure is 0.2~0.4 MPa and the blowing time is 10~20 seconds.

[0034] Step S5: Clean the debonded wafer.

[0035] Preferably, in step S5 of this embodiment, the debonded wafer is transferred to a rotating platform, and a ring-shaped fixing member is used to press against the non-circuit area of ​​the wafer edge for rigid fixation. The ring-shaped fixing member is a metal ring, and the metal ring pressure is 0.5~1.0 MPa. Subsequently, the wafer surface is cleaned and dried. Specifically, in this embodiment, the rotation speed is 100~200 rpm. Example 2

[0036] Combination Figure 2As shown, the thin wafer bumping process system in this embodiment adopts the thin wafer bumping process method in Embodiment 1, and specifically includes the following modules: Temporary bonding module, used to bond thin wafers and glass substrates into a composite structure using a temporary bonding adhesive layer; A bump manufacturing module is used to perform bump processing on the composite structure; The laser debonding module is used to irradiate a glass substrate with a laser to cause the temporary bonding adhesive layer to fail, thus separating the wafer from the substrate; A cleaning module for rotating and cleaning wafers includes a rotating platform and an annular fixing member, which is used to press against the edge area of ​​the thin wafer for fixation during cleaning.

[0037] Many specific details have been set forth in the foregoing description to provide a thorough understanding of the present invention. However, the above description is merely a preferred embodiment of the present invention, and the present invention can be implemented in many other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A bumping process for thin wafers, characterized in that: Temporarily bonding the glass substrate to the thin wafer involves the following steps: Step S1: Surface treatment: Cleaning and activation treatment of the bonding surfaces of the glass substrate and the wafer; Step S2: Temporary bonding: Apply bonding adhesive to the bonding surface of the glass substrate, then align and press the wafer with the glass substrate coated with temporary bonding adhesive to form a rigid composite structure. Step S3: Bump manufacturing: Perform a bump manufacturing process on the composite structure; Step S4: Laser debonding: Laser debonding is performed after the bump manufacturing is completed; Step S5: Clean the debonded wafer.

2. The thin wafer bumping process method according to claim 1, characterized in that: Step S1 specifically includes the following steps: Step S101: Spray deionized water onto the bonding surfaces of the glass substrate and the wafer to completely cover the bonding surfaces; Step S102: Perform hydrophobic treatment on the bonding surface between the glass carrier and the wafer; Step S103: Perform scanning cleaning on the bonding surfaces of the glass carrier and the wafer.

3. The thin wafer bumping process method according to claim 1, characterized in that: The glass slide is a borosilicate glass slide.

4. The thin wafer bumping process method according to claim 1, characterized in that: In step S2, the thickness of the bonding adhesive is 0.5~1.0 μm.

5. The thin wafer bumping process method according to claim 1, characterized in that: In step S4, a laser beam is used to irradiate the temporary bonding adhesive layer through the glass substrate, causing the adhesive layer to carbonize or ablate at the interface, thereby achieving non-destructive separation of the wafer from the glass substrate.

6. The thin wafer bumping process method according to claim 4, characterized in that: The laser wavelength is 355 nm, the single-pulse energy density is 400~600 mJ / cm², and the scanning interval is 50~70 μm.

7. The thin wafer bumping process method according to claim 4, characterized in that: The carbonized adhesive residue was removed by blowing with a gas gun, and the bonding was checked to see if it was completely broken.

8. The thin wafer bumping process method according to claim 1, characterized in that: In step S5, the debonded wafer is transferred to a rotating platform, and a ring-shaped fixing member is used to press onto the non-circuit area of ​​the wafer edge for rigid fixation. Subsequently, the wafer surface is cleaned and dried.

9. A thin wafer bumping process system, characterized in that: The thin wafer bumping process method according to any one of claims 1-8 specifically includes the following modules: Temporary bonding module, used to bond thin wafers and glass substrates into a composite structure using a temporary bonding adhesive layer; A bump manufacturing module is used to perform bump processing on the composite structure; The laser debonding module is used to irradiate a glass substrate with a laser to cause the temporary bonding adhesive layer to fail, thus separating the wafer from the substrate; A cleaning module for rotating and cleaning wafers includes a rotating platform and an annular fixing member, which is used to press against the edge area of ​​the thin wafer for fixation during cleaning.

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