A method for manufacturing a metal wiring layer and a packaging structure

Abstract

The present invention provides a method for manufacturing a metal wiring layer and a packaging structure, the packaging structure comprising a wafer, a separation layer formed on the surface of the wafer; a rewiring layer dielectric layer formed on the surface of the separation layer; a patterned seed layer formed on the surface of the rewiring layer dielectric layer; a copper metal layer formed on the surface of the seed layer; the patterned seed layer and the copper layer formed on the surface of the seed layer constitute a metal wire wiring layer. The deionized water soaking step of the present invention can significantly reduce the temperature of the wafer, reduce the generation of CuO in the rinsing and drying process, and the obtained Cu layer has good appearance and electrical properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor packaging, and in particular relates to a manufacturing method and a packaging structure of a metal wiring layer. Background Art

[0002] Wafer Level Packaging (WLP) is a technical method that performs most or even all packaging and testing procedures directly on the wafer, and then cuts (Singulation) into single chips (Chip). It has the advantages of high packaging density, fast packaging speed and low cost.

[0003] In the WLP process, the photoresist needs to be removed after the copper layer is electroplated. During this process, CuO is easily formed on the Cu layer, which not only affects the appearance, but also causes the degradation of electrical properties and surface bonding properties. Therefore, it is necessary to provide a method for manufacturing a metal wiring layer and a packaging structure to reduce the CuO generated on the Cu surface after the photoresist removal process and improve the appearance and electrical properties of the copper layer. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for manufacturing a metal wiring layer and a packaging structure, so as to solve the problem of CuO generated on the Cu surface after removing the photoresist process in the prior art.

[0005] To achieve the above-mentioned purpose and other related purposes, the present invention provides a method for manufacturing a metal wiring layer, comprising the steps of: providing a wafer; forming a separation layer; forming a redistribution layer dielectric layer; depositing a seed layer on the dielectric layer; depositing a photoresist on the seed layer, and patterning the photoresist to form a window, wherein the window exposes the seed layer; electroplating copper in the window based on the seed layer to form a copper metal layer; removing the photoresist to expose the seed layer, wherein removing the photoresist comprises: using a degumming solution to remove the photoresist film layer, using deionized water to soak the copper metal layer, using deionized water to rinse the remaining photoresist, and finally using nitrogen to blow dry; removing the exposed seed layer to form a metal wiring layer.

[0006] Optionally, the deionized water soaking time is 30 to 60 seconds.

[0007] Optionally, the deionized water immersion temperature ranges from 10 to 40°C.

[0008] Optionally, the material of the redistribution layer dielectric layer includes one or a combination of two or more of epoxy resin, silicone, PI, BPO, BCB, silicon oxide, phosphosilicate glass, and fluorine-containing glass, and the method of forming the redistribution layer dielectric layer includes one of plastic sealing process, compression molding, transfer molding, liquid sealing molding, vacuum lamination molding and spin coating molding.

[0009] Optionally, the seed layer includes a Ti / Cu seed layer, and a method of depositing the Ti / Cu seed layer includes one or a combination of sputtering, chemical plating, and electroplating.

[0010] Optionally, the degumming solution includes a degumming solution containing dimethyl sulfoxide, ethylene glycol, N-methyl-2-pyrrolidone and tetramethylammonium hydroxide.

[0011] Optionally, the method for manufacturing the metal wiring layer includes a preparation method for wafer-level semiconductor packaging.

[0012] The present invention also provides a packaging structure, which includes: a wafer; a separation layer formed on the surface of the wafer; a redistribution layer dielectric layer formed on the surface of the separation layer; a patterned seed layer formed on the surface of the redistribution layer dielectric layer; a copper metal layer formed on the surface of the seed layer; the patterned seed layer and the copper metal layer formed on the surface of the seed layer constitute a metal wiring layer.

[0013] Optionally, the surface of the Cu metal layer is bright and has no CuO attached.

[0014] Optionally, the material of the redistribution layer dielectric layer includes one of epoxy resin, silica gel, PI, BPO, BCB, silicon oxide, phosphosilicate glass, and fluorine-containing glass.

[0015] Optionally, the seed layer includes a Ti / Cu seed layer.

[0016] Optionally, the metal wiring layer is in the shape of mutually independent metal wires, mutually intersecting metal meshes, or a combination of the above two, and the grid of the metal mesh is rectangular, rhombus, triangle, or a combination thereof.

[0017] As described above, the method for manufacturing the metal wiring layer and the packaging structure of the present invention have the following beneficial effects: the deionized water immersion step can isolate oxygen and significantly cool the wafer, and then due to the lowered temperature and drying in a nitrogen atmosphere, it is not easy to oxidize to form CuO, and the obtained Cu layer has good appearance and electrical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A flowchart showing a method for manufacturing a metal wiring layer according to the present invention is shown.

[0019] Figure 2-9 It is a schematic diagram showing the structure of each step of the method for making a metal wiring layer of the present invention; wherein, Fig. 9 Shown is a schematic diagram of the packaging structure of the present invention.

[0020] Component number description:

[0021] 100 Semiconductor Structure

[0022] 101 Wafer

[0023] 102 Separation Layer

[0024] 200 Rewiring layer Dielectric layer

[0025] 300 Ti / Cu seed layer

[0026] 301 Ti metal layer

[0027] 302 Cu metal layer

[0028] 400 Photoresist layer

[0029] 500 Electroplated Cu metal layer

[0030] Steps S1 to S9 DETAILED DESCRIPTION

[0031] The following describes the implementation of the present invention through specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0032] See also Figures 1 to 9 It should be noted that the illustrations provided in this embodiment are only schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the layout of the components may also be more complicated.

[0033] like Figure 1 As shown, the present invention provides a method for manufacturing a metal wiring layer, and the method for manufacturing a metal wiring layer includes a preparation method for wafer-level semiconductor packaging, but is not limited thereto. The manufacturing method includes: Figure 1 In steps S1 to S9 shown, the present invention introduces a deionized water soaking process during the photoresist removal process, thereby isolating oxygen and significantly cooling the wafer, reducing CuO generated in the Cu layer, and obtaining a Cu layer with good appearance and electrical properties.

[0034] like Figure 2 to Figure 9 As shown, the method for manufacturing the metal wiring layer includes the following steps:

[0035] like Figure 1 and Figure 2As shown, firstly, steps S1 to S2 are performed to provide a semiconductor structure 100, wherein the semiconductor structure includes a wafer 101 and a separation layer 102 formed on the upper surface of the wafer. The separation layer 102 may include one of an adhesive tape and a polymer layer. For example, the separation layer 102 may be a photothermal conversion layer, so that the subsequent process may heat the photothermal conversion layer by laser or the like, so that the supporting base wafer 101 is separated from the photothermal conversion layer, thereby improving the convenience of operation.

[0036] like Figure 1 and 3 As shown, step S3 is then performed to form a redistribution layer dielectric layer 200 on the upper surface of the semiconductor structure 100 .

[0037] The material of the redistribution layer dielectric layer includes one or a combination of two or more of epoxy resin, silicone, PI, BPO, BCB, silicon oxide, phosphosilicate glass, and fluorine-containing glass. The method of forming the redistribution layer dielectric layer includes one of plastic sealing process, compression molding, transfer molding, liquid sealing molding, vacuum lamination molding, and spin coating molding.

[0038] like Figure 1 and Figure 4 As shown, step S4 is then performed to form a Ti / Cu metal seed layer 300 on the upper surface of the rewiring layer dielectric layer 200, wherein the method for preparing the Ti / Cu metal seed layer includes one or a combination of sputtering, chemical plating, and electroplating. The present invention sputters a Ti metal layer 301 and a Cu metal layer 302 on the rewiring layer dielectric layer 200 in sequence.

[0039] The thickness of the Ti metal layer may be between 2 nm and 10 nm, and the thickness of the Cu metal layer may be between 2 nm and 10 nm. However, the thickness of the Ti metal layer and the Cu metal layer may be set as required and are not limited here.

[0040] like Figure 1 and Figure 5 As shown, step S5 is then performed to form a photoresist layer 400 on the upper surface of the Ti / Cu metal seed layer 300. Specifically, the photoresist layer 400 can be formed on the upper surface of the Ti / Cu metal seed layer 300 by spin coating to further improve the uniformity of the photoresist layer 400, but it is not limited thereto. The thickness of the photoresist layer can be selected as needed and is not limited here.

[0041] like Figure 1 and Figure 6As shown, after the photoresist layer 400 is formed, step S6 is performed to expose and develop the photoresist layer 400 to form a groove in the photoresist layer 400 to expose the Ti / Cu metal seed layer 300 for preparing RDL metal wiring.

[0042] like Figure 1 and Figure 7 As shown, step S7 is then performed, using the patterned photoresist layer 400 as a mask to deposit a Cu metal layer 500 to prepare RDL metal wiring. The shape of the RDL metal wiring can be independent metal wires, intersecting metal meshes, or a combination of the two. The shape can also be selected according to the required wiring function to achieve the corresponding electrical function. The grid of the metal mesh can be a rectangle, a diamond, a triangle, etc. or a combination thereof. The thickness of the RDL metal wiring can be between 1 micron and 200 microns, but is not limited to this range. The RDL metal wiring can also be subsequently transferred to the target device through a bonding process to achieve its wiring function.

[0043] like Figure 1 and Figure 8 As shown, after depositing the metal copper, step S8 is then performed to remove the photoresist layer 400. In this embodiment, the process of removing the photoresist layer 400 includes:

[0044] First, the photoresist film layer is removed by using a degumming solution, wherein the degumming solution may contain dimethyl sulfoxide, ethylene glycol, N-methyl-2-pyrrolidone and tetramethylammonium hydroxide.

[0045] Then, the substrate is immersed in deionized water for 30 to 60 seconds. The temperature of the deionized water immersion ranges from 10 to 40° C., for example, the temperature of the deionized water immersion can be 25° C.

[0046] Next, use deionized water to rinse the residual glue.

[0047] Finally, N2 is used for drying to obtain a bright Cu pad.

[0048] Compared with the process of directly using N2 drying, the direct use of N2 drying lacks the deionized water soaking process, and the wafer temperature is high during N2 drying, CuO is easily generated on the pad, and the obtained pad is dark brown. This embodiment introduces a deionized water soaking process during the photoresist removal process, which can isolate the copper metal layer from oxygen when the surface temperature is high and significantly cool the wafer, thereby reducing the CuO generated in the Cu layer. The obtained Cu layer changes from dark brown in the traditional process to bright, has good appearance and electrical properties, and improves the bonding ability.

[0049] like Figure 1 and 9Finally, step S9 is performed to etch away the exposed portion of the Ti / Cu metal seed layer to form an RDL metal line. The etching method includes a chemical etching process.

[0050] The chemical etching process is to immerse the wafer in a certain chemical reagent or reagent solution, and the thin layer on the surface of the pad and the Ti / Cu metal seed layer react with the chemical reagent and are removed.

[0051] like Fig. 9 As shown, this embodiment also provides a packaging structure, including a wafer 101; a separation layer 102, formed on the surface of the wafer; a rewiring layer dielectric layer 200, formed on the surface of the separation layer; a patterned Ti / Cu seed layer 300, formed on the surface of the rewiring layer dielectric layer; a Cu metal layer 500, formed on the surface of the Ti / Cu seed layer; the patterned Ti / Cu seed layer 300 and the Cu layer 500 formed on the surface of the Ti / Cu seed layer constitute the RDL metal line. The surface of the Cu metal layer is bright and has no CuO attached. The material of the rewiring layer dielectric layer includes one of epoxy resin, silica gel, PI, BPO, BCB, silicon oxide, phosphorus silicon glass, and fluorine-containing glass.

[0052] In summary, the present invention introduces a deionized water soaking process during the photoresist removal process, isolates oxygen and significantly cools the wafer, reduces the CuO generated in the Cu layer, and changes the obtained Cu layer from dark brown in the traditional process to bright, with good appearance and electrical properties, and improves the bonding ability. Therefore, the present invention effectively overcomes the shortcomings of the prior art and has a high industrial value.

[0053] 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 familiar with 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 a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for manufacturing a metal wiring layer, characterized in that: Includes steps: Provide wafers; forming a separation layer; forming a redistribution layer dielectric layer; depositing a seed layer on the dielectric layer; Depositing a photoresist on the seed layer, and patterning the photoresist to form a window, wherein the window exposes the seed layer; Electroplating copper in the window based on the seed layer to form a copper metal layer; Removing the photoresist to expose the seed layer, wherein removing the photoresist comprises: removing the photoresist film layer with a degumming solution, soaking the copper metal layer with deionized water, washing the remaining photoresist with deionized water, and finally drying with nitrogen gas; The exposed seed layer is removed to form a metal wiring layer.

2. The method for manufacturing a metal wiring layer according to claim 1, characterized in that: The deionized water soaking time is 30 to 60 seconds.

3. The method for manufacturing a metal wiring layer according to claim 1, characterized in that: The temperature range of the deionized water soaking is between 10 and 40°C.

4. The method for manufacturing a metal wiring layer according to claim 1, characterized in that: The material of the redistribution layer dielectric layer includes one or a combination of two or more of epoxy resin, silicone, PI, BPO, BCB, silicon oxide, phosphosilicate glass, and fluorine-containing glass. The method of forming the redistribution layer dielectric layer includes one of plastic sealing process, compression molding, transfer molding, liquid sealing molding, vacuum lamination molding, and spin coating molding.

5. The method for manufacturing a metal wiring layer according to claim 1, characterized in that: The seed layer includes a Ti / Cu seed layer, and a method of depositing the Ti / Cu seed layer includes one or a combination of sputtering, chemical plating, and electroplating.

6. The method for manufacturing a metal wiring layer according to claim 1, characterized in that: The degumming solution includes a degumming solution containing dimethyl sulfoxide, ethylene glycol, N-methyl-2-pyrrolidone and tetramethylammonium hydroxide.

7. The method for manufacturing a metal wiring layer according to any one of claims 1 to 6, characterized in that: The method for manufacturing the metal wiring layer includes a method for manufacturing a wafer-level semiconductor package.

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