A bonding method and bonding structure for reducing bubble formation in temporary bonding process

Abstract

The present invention provides a bonding method and bonding structure for reducing bubble formation in a temporary bonding process. By adding a plasma treatment process, the surface of a redistribution dielectric layer is roughened, making it hydrophilic, thereby facilitating the fluidity of a temporary bonding adhesive, achieving close contact between the temporary bonding adhesive and the redistribution dielectric layer, reducing the generation of bubbles in a subsequent high-temperature CVD process, thereby reducing the risk of edge rupture, and improving product yield and productivity.

Description

Technical Field

[0001] The present invention belongs to the field of advanced packaging, and in particular relates to a bonding method and a bonding structure for reducing bubble formation in a temporary bonding process. Background Art

[0002] With the rapid development of integrated circuit technology and the continuous improvement of chip performance, people are placing increasingly higher demands on corresponding packaging technologies. Since 2010, the emergence of intermediate packaging technologies such as wafer-level packaging (WLP), through-silicon vias (TSV), 2.5D interposers, 3DIC, and fan-out have greatly advanced the state of advanced packaging technology. Currently, with the slowdown of Moore's Law, packaging technology has become a key means to miniaturize, enhance multifunctionality, reduce power consumption, and increase bandwidth in electronic products. Advanced packaging technology is developing towards system integration, high speed, high frequency, and 3D.

[0003] In a 2.5D transfer plate processing platform, a glass substrate and a thinned silicon wafer need to be bonded together. However, during this bonding process, bubbles will appear in the subsequent high-temperature CVD. Bubbles will destroy the precision of the chemical mechanical polishing (CMP) process. The stability of the process is affected and the yield of the product is reduced. Therefore, reducing the bubbles generated during the temporary bonding and subsequent high-temperature CVD process is a technical difficulty faced by this field and is also the key to improving the quality competitiveness of packaging products. Summary of the Invention

[0004] In 2.5D adapter plate packaging technology, the substrate and thinned silicon wafer need to be temporarily bonded together. However, during the subsequent high-temperature CVD process, bubbles are easily generated at the bonding interface, affecting the accuracy of the subsequent CMP process and reducing process stability and product yield.

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a bonding method for reducing bubble formation during a temporary bonding process, so as to solve the problem of bubble generation during a temporary bonding process in the prior art.

[0006] To achieve the above-mentioned purpose and other related purposes, the present invention provides a bonding method for reducing bubble formation in a temporary bonding process, comprising the following steps: 1) providing a pad structure, comprising a substrate, a metal-filled TSV deep hole located in the substrate, a redistribution dielectric layer located on the surface of the substrate, and a metal electrode located on the redistribution dielectric layer; 2) cutting off the edges and corners of the substrate; 3) using plasma to treat the redistribution dielectric layer so that its surface has a roughened structure, thereby improving the hydrophilicity of the redistribution dielectric layer; 4) providing a substrate, and bonding the pad structure to the substrate using an adhesive layer.

[0007] Optionally, the material of the redistribution dielectric layer includes one or a combination of two or more of PI, epoxy resin, silica gel, BPO, BCB, silicon oxide, phosphosilicate glass, and fluorine-containing glass.

[0008] Optionally, the metal filling includes one of copper, gold, and silver filling; and the metal electrode is a copper-nickel-gold three-layer metal electrode.

[0009] Optionally, the method of cutting off the corners of the substrate includes one of blade cutting and grinding wheel cutting.

[0010] Optionally, the plasma includes plasma obtained by exciting O2 using a magnetic field, wherein the magnetic field power range is between 400 and 2000 W, the O2 flow range is between 400 and 1600 sccm, the gas pressure range is between 400 and 1600 mtorr, and the processing time range is between 20 and 120 seconds.

[0011] Optionally, the adhesive layer includes one of PI glue, PVB glue, and EVA glue, the bonding method includes one of compression molding, transfer molding, liquid sealing molding, plastic sealing process, and vacuum lamination process, and the substrate includes one of glass substrate, metal substrate, semiconductor substrate, polymer substrate, and ceramic substrate.

[0012] The present invention also provides a bonding structure, which at least includes: a pad structure, including a substrate, a metal-filled TSV deep hole located in the substrate, a redistribution dielectric layer located on the surface of the substrate, and a metal electrode located on the redistribution dielectric layer, wherein the surface of the redistribution dielectric layer has a roughened structure after plasma treatment; an adhesive layer formed on the redistribution dielectric layer; and a substrate attached to the adhesive layer.

[0013] Optionally, the substrate is a substrate with cut corners.

[0014] Optionally, the metal filling includes one of copper, gold, and silver filling; the metal electrode is a copper-nickel-gold three-layer metal electrode, and the material of the redistribution dielectric layer includes one of PI, epoxy resin, silicone, BPO, BCB, silicon oxide, phosphosilicate glass, and fluorine-containing glass.

[0015] Optionally, the adhesive layer includes one of PI adhesive, PVB adhesive, and EVA adhesive, and the substrate includes one of a glass substrate, a metal substrate, a semiconductor substrate, a polymer substrate, and a ceramic substrate.

[0016] As described above, the present invention provides a bonding method and bonding structure for reducing the formation of bubbles in the temporary bonding process, which has the following beneficial effects: the present invention adds a plasma treatment process to roughen the surface of the redistribution dielectric layer, making it have good hydrophilicity, which is beneficial to the fluidity of the temporary bonding adhesive, achieves close contact between the temporary bonding adhesive and the redistribution dielectric layer, reduces the generation of bubbles, and thus reduces the risk of edge rupture, which can improve product output and increase productivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of a bonding method for reducing bubble formation in a temporary bonding process using the present invention.

[0018] Figures 2 to 5 Shown is a schematic diagram of a bonding method for reducing bubble formation in a temporary bonding process according to the present invention, wherein: Figure 5 Shown is a schematic diagram of a bonding structure of the present invention.

[0019] Component number description

[0020] 100U type pad

[0021] 101 silicon wafer

[0022] 102TSV deep hole

[0023] 103 redistribution dielectric layer

[0024] 104 copper layer

[0025] 105 nickel layer

[0026] 106 Gold Layer

[0027] 200 cutter

[0028] 300 plasma

[0029] 400 adhesive layers

[0030] 500 substrates

[0031] Steps S1 to S4 DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0033] For example, when describing the embodiments of the present invention, cross-sectional views of device structures may be partially enlarged to scale for ease of explanation. Furthermore, these schematic views are merely illustrative and should not limit the scope of the present invention. Furthermore, in actual manufacturing, three-dimensional dimensions, including length, width, and depth, should be included.

[0034] For convenience, spatially relative terms such as "under," "below," "below," "below," "above," and "on" may be used herein to describe the relationship of one element or feature to other elements or features shown in the drawings. It will be understood that these spatially relative terms are intended to encompass orientations of the device in use or operation in addition to the orientation depicted in the drawings. Additionally, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

[0035] In the context of the present application, a structure described as a first feature being "above" a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where an additional feature is formed between the first and second features, such that the first and second features may not be in direct contact.

[0036] See Figures 1 to 5 It should be noted that the diagrams provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0037] To achieve high-density packaging, in the 2.5D adapter plate packaging solution, the substrate and the thinned silicon wafer are temporarily bonded together through a glue layer. However, during the subsequent high-temperature CVD process, bubbles are easily generated at the bonding interface, affecting the accuracy of the subsequent chemical mechanical polishing process. Figure 1 The present invention provides a bonding method for reducing bubble formation during a temporary bonding process, comprising the steps of: 1) providing a U-shaped pad; 2) cutting off corners of a substrate; 3) removing a bottom film from a dielectric layer using plasma; and 4) temporarily bonding the U-shaped pad to the substrate using an adhesive layer.

[0038] like Figure 2As shown, first, step 1) S1 is performed to provide a pad structure, for example, a U-shaped pad 100 is provided. The U-shaped pad 100 includes a silicon wafer 101, the back side of the silicon wafer 101 is thinned to a target thickness by grinding or etching, a metal-filled TSV deep hole 102 on the silicon wafer 101, a redistribution dielectric layer 103 on the surface of the silicon wafer, and a metal electrode on the redistribution dielectric layer 103; the material of the redistribution dielectric layer can be one or a combination of two or more of PI, epoxy resin, silica gel, BPO, BCB, silicon oxide, phosphosilicate glass, and fluorine-containing glass. The metal filling of the TSV deep hole includes one of copper, gold, and silver filling. The metal electrode is a three-layer metal electrode of copper layer 104-nickel layer 105-gold layer 106, and the manufacturing method of the metal electrode can be one or a combination of sputtering, chemical plating, and electroplating.

[0039] like Figure 3 As shown, step 2) S2 is then performed, wherein the blade 200 is used to cut off the corners of the silicon wafer 101 to reduce the possible deviation in the subsequent temporary bonding process. The corners of the silicon wafer 101 can also be cut by a grinding wheel.

[0040] like Figure 4 As shown, step 3) S3 is then performed, wherein a magnetic field is used to excite O2 to obtain plasma 300, and the redistribution dielectric layer is subjected to plasma treatment to provide a roughened surface structure and improve the hydrophilicity of the redistribution dielectric layer. In this embodiment, the magnetic field power of the plasma obtained by exciting O2 can be between 400 and 2000 W, the O2 flow rate can be between 400 and 1600 sccm, the gas pressure can be between 400 and 1600 mtorr, and the treatment time can be between 20 and 120 seconds. In a specific implementation process, the magnetic field power of the plasma obtained by exciting O2 can be 1000 W, the O2 flow rate can be 800 sccm, the gas pressure can be 800 mtorr, and the treatment time can be 60 seconds.

[0041] like Figure 5As shown, step 4) S4 is then performed to provide a substrate 500, and the U-shaped pad 100 is temporarily bonded to the substrate 500 using the adhesive layer 400. The adhesive layer 400 can be one of PI adhesive, PVB adhesive, and EVA adhesive. The initial form of the adhesive layer is liquid, and can be formed on the redistribution dielectric layer by a coating process or a dispensing process. Since the present invention roughens the surface of the redistribution dielectric layer by adding a plasma treatment process, it has good hydrophilicity, which is beneficial to improve the fluidity of the temporary bonding adhesive, achieve close contact, reduce the generation of bubbles, and thus reduce the risk of edge breakage, which can improve the output of the product and increase the yield. Then, the glass substrate is contacted with the adhesive layer and the adhesive layer is cured to temporarily bond the U-shaped pad 100 to the substrate 500. The temporary bonding method includes one of compression molding, transfer molding, liquid sealing molding, plastic sealing process, and vacuum lamination process. The substrate 500 includes one of a glass substrate, a metal substrate, a semiconductor substrate, a polymer substrate, and a ceramic substrate.

[0042] like Figure 5 As shown, this embodiment further provides a bonding structure, which at least includes: a U-shaped pad 100 , an adhesive layer 400 and a substrate 500 .

[0043] The U-shaped pad 100 includes a silicon wafer 101, a metal-filled TSV deep hole 102 on the silicon wafer, a redistribution dielectric layer 103 on the silicon wafer surface, and a metal electrode on the redistribution dielectric layer 103; the redistribution dielectric layer 103 is plasma-treated to provide a roughened surface structure, thereby increasing the hydrophilicity of the redistribution dielectric layer. For example, the silicon wafer 101 can be a silicon wafer with trimmed edges. The metal filling includes one of copper, gold, and silver filling; the metal electrode is a copper-nickel-gold three-layer metal electrode, and the material of the redistribution dielectric layer includes one of PI, epoxy resin, silicone, BPO, BCB, silicon oxide, phosphosilicate glass, and fluorine-containing glass.

[0044] The adhesive layer 400 is formed on the redistribution dielectric layer and includes one of PI adhesive, PVB adhesive, and EVA adhesive.

[0045] The substrate 500 is attached to the adhesive layer and includes one of a glass substrate, a metal substrate, a semiconductor substrate, a polymer substrate, and a ceramic substrate.

[0046] In summary, the present invention, through the addition of a plasma base film removal process, roughens the surface of the redistribution dielectric layer, imparting excellent hydrophilicity. This improves the fluidity of the temporary bonding adhesive, achieving close contact between the temporary bonding adhesive and the redistribution dielectric layer, and reduces the generation of bubbles, thereby lowering the risk of edge cracking, thereby increasing product production and yield. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and possesses high industrial value.

[0047] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A bonding method for reducing bubble formation in a temporary bonding process, characterized in that: Including steps: 1) Providing a pad structure, including a substrate, a metal-filled TSV deep hole located in the substrate, a redistribution dielectric layer located on a surface of the substrate, and a metal electrode located on the redistribution dielectric layer; 2) cutting off the corners of the substrate; 3) treating the redistribution dielectric layer with plasma to provide a roughened surface structure and improve the hydrophilicity of the redistribution dielectric layer; 4) Providing a substrate, and bonding the pad structure to the substrate using an adhesive layer, wherein the adhesive layer is initially in liquid form and is formed on the redistribution dielectric layer through a coating process or a dispensing process, and then contacting the substrate with the adhesive layer and curing the adhesive layer to temporarily bond the pad structure to the substrate.

2. The bonding method for reducing bubble formation in a temporary bonding process according to claim 1, wherein: The material of the redistribution dielectric layer includes one or a combination of two or more of PI, epoxy resin, silica gel, BPO, BCB, silicon oxide, phosphosilicate glass, and fluorine-containing glass.

3. The bonding method for reducing bubble formation in a temporary bonding process according to claim 1, wherein: The metal filling includes one of copper, gold and silver filling; the metal electrode is a copper-nickel-gold three-layer metal electrode.

4. The bonding method for reducing bubble formation during temporary bonding according to claim 1, wherein: The method of cutting off the corners of the substrate includes one of blade cutting and grinding wheel cutting.

5. The bonding method for reducing bubble formation in a temporary bonding process according to claim 1, wherein: The plasma includes plasma obtained by exciting O2 with a magnetic field, wherein the magnetic field power range is between 400 and 2000 W, the O2 flow range is between 400 and 1600 sccm, the gas pressure range is between 400 and 1600 mtorr, and the processing time range is between 20 and 120 seconds.

6. The bonding method for reducing bubble formation during a temporary bonding process according to claim 1, wherein: The adhesive layer includes one of PI adhesive, PVB adhesive, and EVA adhesive; the bonding method includes one of compression molding, transfer molding, liquid sealing molding, plastic sealing process, and vacuum lamination process; the substrate includes one of glass substrate, metal substrate, semiconductor substrate, polymer substrate, and ceramic substrate.

7. A bonding structure formed by the bonding method for reducing bubble formation in a temporary bonding process according to any one of claims 1 to 6, characterized in that: The structure shall include at least: A pad structure comprising a substrate, a metal-filled TSV deep hole located in the substrate, a redistribution dielectric layer located on a surface of the substrate, and a metal electrode located on the redistribution dielectric layer, wherein the surface of the redistribution dielectric layer has a roughened structure after plasma treatment; a glue layer formed on the redistribution dielectric layer; The substrate is attached to the adhesive layer.

8. The bonding structure according to claim 7, wherein: The substrate is a substrate with corners cut off, and the substrate includes a silicon wafer.

9. The bonding structure according to claim 7, wherein: The metal filling includes one of copper, gold, and silver filling; the metal electrode is a copper-nickel-gold three-layer metal electrode, and the material of the redistribution dielectric layer includes one of PI, epoxy resin, silicone, BPO, BCB, silicon oxide, phosphosilicate glass, and fluorine-containing glass.

10. The bonding structure according to claim 7, wherein: The adhesive layer includes one of PI adhesive, PVB adhesive, and EVA adhesive, and the substrate includes one of a glass substrate, a metal substrate, a semiconductor substrate, a polymer substrate, and a ceramic substrate.

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