Laminated film for wafer back grinding

Abstract

The utility model relates to a laminated film for wafer back grinding, and belongs to the technical field of semiconductors. The laminated film for grinding the back surface of the wafer comprises a release layer, an ultraviolet curing visbreaking layer, a first buffer layer, a first base material layer, a second buffer layer, a second base material layer and a third buffer layer which are arranged in sequence, the first buffer layer, the second buffer layer and the third buffer layer are made of different materials. And a multi-layer composite structure is adopted, so that embedding of the bump bumps and protection of the surface of the wafer are realized. Particularly, the first buffer layer, the second buffer layer and the third buffer layer are compounded, so that the elasticity of the laminated film is remarkably improved, and embedding of the bulges is realized. Through the design of the ultraviolet curing visbreaking layer, no pollution on the surface of the wafer is realized. Through the design of the double base material layers, the laminated film is more flexible, has better fitting performance and has better embedding performance on bump bumps. In the use process of the laminated film for wafer back grinding, no residue is left on the surface of a wafer, the wafer is small in warping after grinding, and water seepage is avoided in the grinding process.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor technology, and in particular relates to a laminated film for wafer backside polishing. Background Technology

[0002] Semiconductor wafers are used in a variety of applications, such as personal computers, smartphones, and automobiles. In the semiconductor wafer fabrication process, pressure-sensitive adhesive sheets are used to protect the surface of the wafer during processing. In recent years, the miniaturization and increasing functionality of large-scale integrated circuits (LSI) have developed rapidly, resulting in more complex surface structures for wafers, especially semiconductor wafers with uneven structures such as bumps.

[0003] Bumps are protrusions with metallic conductivity that are directionally grown on the surface of a chip and directly or indirectly connected to the chip pads. The height of bumps is about 60μm-100μm and the diameter is about 80μm-125μm. The materials are generally Si, GaAs, glass and other materials.

[0004] When protecting the surface of a wafer containing bumps, existing protective tapes cannot effectively embed the bumps and therefore cannot meet application requirements. Utility Model Content

[0005] To solve the above-mentioned technical problems, this utility model provides a laminated film for wafer backside grinding.

[0006] The purpose of this invention is to provide a laminated film for back-side grinding of wafers, the laminated film for back-side grinding of wafers comprising a release layer, an ultraviolet-cured anti-adhesion layer, a first buffer layer, a first substrate layer, a second buffer layer, a second substrate layer, and a third buffer layer arranged sequentially; the materials of the first buffer layer, the second buffer layer, and the third buffer layer are all different.

[0007] In one embodiment of this utility model, the release layer is selected from release film or release paper.

[0008] Furthermore, the release film is selected from PET release film, PE release film or PP release film.

[0009] In one embodiment of this utility model, the thickness of the release film is 25μm-100μm, and the release force is 15gf / 25mm-150gf / 25mm.

[0010] Further, the thickness of the release film is 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, 56μm, 57μm, 58μm, etc. μm, 59μm, 60μm, 61μm, 62μm, 63μm, 64μm, 65μm, 66μm, 67μm, 68μm, 69μm, 70μm, 71μm, 72μm, 73μm, 74μm, 75μm, 76 μm, 77μm, 78μm, 79μm, 80μm, 81μm, 82μm, 83μm, 84μm, 85μm, 86μm, 87μm, 88μm, 89μm, 90μm, 91μm, 92μm, 93μm, 94μm The thicknesses are 95μm, 96μm, 97μm, 98μm, 99μm, 100μm; or any thickness value between any two values; the release force is 15gf / 25mm, 20gf / 25mm, 25gf / 25mm, 30gf / 25mm, 35gf / 25mm, 40gf / 25mm, 45gf / 25mm, 50gf / 25mm, 55gf / 25mm, 60gf / 25mm, 65gf / 25mm, 70gf / 25mm, 75gf / 25mm. 5mm, 80gf / 25mm, 85gf / 25mm, 90gf / 25mm, 95gf / 25mm, 100gf / 25mm, 105gf / 25mm, 110gf / 25mm, 115gf / 25mm, 120gf / 25mm, 125gf / 25mm, 130gf / 25mm, 135gf / 25mm, 140gf / 25mm, 145gf / 25mm, 150gf / 25mm; or any release force between any two values.

[0011] In one embodiment of this utility model, the basis weight of the release paper is 40 g / m². 2 -80g / m 2 The release force is 15gf / 25mm-150gf / 25mm.

[0012] Furthermore, the basis weight of the release paper is 40 g / m². 2 41g / m 2 42g / m 2 43g / m 2 44g / m 2 45g / m 2 46g / m2 47g / m 2 48g / m 2 49g / m 2 50g / m 2 51g / m 2 52g / m 2 53g / m 2 54g / m 2 55g / m 2 56g / m 2 57g / m 2 58g / m 2 59g / m 2 60g / m 2 61g / m 2 62g / m 2 63g / m 2 64g / m 2 65g / m 2 66g / m 2 67g / m 2 68g / m 2 69g / m 2 70g / m 2 71g / m 2 72g / m 2 73g / m 2 74g / m 2 75g / m 2 76g / m 2 77g / m 2 78g / m 2 79g / m 2 80g / m 2 Or any weight between any two values; the release force is 15gf / 25mm, 20gf / 25mm, 25gf / 25mm, 30gf / 25mm, 35gf / 25mm, 40gf / 25mm, 45gf / 25mm, 50gf / 25mm, 55gf / 25mm, 60gf / 25mm, 65gf / 25mm, 70gf / 25mm, 75gf / 25mm, 80gf / 25mm, 85gf / 25mm. Release force of gf / 25mm, 90gf / 25mm, 95gf / 25mm, 100gf / 25mm, 105gf / 25mm, 110gf / 25mm, 115gf / 25mm, 120gf / 25mm, 125gf / 25mm, 130gf / 25mm, 135gf / 25mm, 140gf / 25mm, 145gf / 25mm, 150gf / 25mm; or any release force between any two values.

[0013] In one embodiment of the present invention, the first buffer layer, the second buffer layer, and the third buffer layer are independently selected from one or more of acrylic resins, acrylic block copolymers, and rubber.

[0014] In one embodiment of this utility model, the thicknesses of the first buffer layer, the second buffer layer, and the third buffer layer are independently 10μm-500μm.

[0015] Furthermore, the thicknesses of the first buffer layer, the second buffer layer, and the third buffer layer are independently 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, etc. μm, 260μm, 270μm, 280μm, 290μm, 300μm, 310μm, 320μm, 330μm, 340μm, 350μm, 360μm, 370μm, 380μm, 390μm, 400μm, 410μm, 420μm, 430μm, 440μm, 450μm, 460μm, 470μm, 480μm, 490μm, 500μm; or any thickness value between any two values.

[0016] In one embodiment of this utility model, the peel strength of the UV-cured anti-adhesion layer after UV irradiation is 5gf / 25mm-100gf / 25mm.

[0017] Furthermore, the peel strength of the UV-cured anti-adhesion layer after UV irradiation is 5gf / 25mm, 10gf / 25mm, 15gf / 25mm, 20gf / 25mm, 25gf / 25mm, 30gf / 25mm, 35gf / 25mm, 40gf / 25mm, 45gf / 25mm, 50gf / 25mm, 55gf / 25mm, 60gf / 25mm, 65gf / 25mm, 70gf / 25mm, 75gf / 25mm, 80gf / 25mm, 85gf / 25mm, 90gf / 25mm, 95gf / 25mm, 100gf / 25mm; or any peel strength between any two values.

[0018] In one embodiment of this utility model, the thickness of the UV-curable anti-adhesion layer is 5μm-50μm.

[0019] Further, the thickness of the UV-curable anti-adhesion layer is 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 2 8μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm; or any thickness value between any two values.

[0020] In one embodiment of this utility model, the first substrate layer and the second substrate layer are independently selected from polyethylene terephthalate film (PET), polyolefin film (PO), polypropylene film (PP), polyethylene film (PE), polyimide film (PI), polyethylene naphthalate film (PEN), or polyamide-imide film (PAI) to provide support, facilitate production and processing, and facilitate die-cutting in use.

[0021] In one embodiment of the present invention, the thickness of the first substrate layer and the second substrate layer are independently 20μm-100μm.

[0022] Further, the thicknesses of the first substrate layer and the second substrate layer are independently 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, 56μm, 57μm, 58μm, and 59μm. m, 60μm, 61μm, 62μm, 63μm, 64μm, 65μm, 66μm, 67μm, 68μm, 69μm, 70μm, 71μm, 72μm, 73μm, 74μm, 75μm, 76μm, 77μm, 78μm, 79μm, 80μm, 81μm, 82μm, 83μm, 84μm, 85μm, 86μm, 87μm, 88μm, 89μm, 90μm, 91μm, 92μm, 93μm, 94μm, 95μm, 96μm, 97μm, 98μm, 99μm, 100μm; or any thickness value between any two values.

[0023] The technical solution of this utility model has the following advantages compared with the prior art:

[0024] (1) The wafer back-side polishing laminated film of this utility model adopts a multi-layer composite structure to achieve embedding of bumps and protection of the wafer surface. In particular, the elasticity of the laminated film is significantly improved by the combination of the first buffer layer, the second buffer layer and the third buffer layer, thus achieving embedding of the bumps.

[0025] (2) The wafer back-side grinding laminated film of the present invention achieves no residue on the wafer surface, minimal wafer warping after grinding, and no water seepage during the grinding process.

[0026] (3) The wafer back-side grinding laminated film of this utility model achieves a non-polluting wafer surface through the design of an ultraviolet light curing anti-sticking layer.

[0027] (4) The wafer back-side grinding laminated film of this utility model has a double substrate layer design, which makes the laminated film more flexible, more conformable, and better for embedding bumps. Attached Figure Description

[0028] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0029] Figure 1 This is a schematic diagram of the structure of the laminated film for wafer backside grinding according to this utility model;

[0030] Explanation of reference numerals in the attached drawings: 1-release layer, 2-UV-cured anti-adhesion layer, 3-first buffer layer, 4-first substrate layer, 5-second buffer layer, 6-second substrate layer, 7-third buffer layer. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0032] In this utility model, unless otherwise stated, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this utility model 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 this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0033] In this utility model, unless otherwise stated, the terms "set", "connected", and "linked" 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; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0034] In this invention, unless otherwise specified, a thickness gauge is used to measure the thickness of the substrate layer, the puncture-resistant layer and the adhesive layer. The specific test standard refers to GB / T 7125-2014.

[0035] In this utility model, unless otherwise stated, the preparation of the adhesive used in the UV-curable anti-tack layer in the embodiments specifically includes the following steps: weigh 100g of UV-curable anti-tack adhesive (purchased from Changxing Chemical, model 7768U), 0.4g of curing agent L-75, and 0.6g of photoinitiator TPO, mix thoroughly and evenly, and let stand for 30 minutes to remove bubbles to obtain the adhesive.

[0036] In this invention, unless otherwise stated, the acrylic resin used in the embodiments was purchased from Changxing Chemical, model 7770R.

[0037] In this invention, unless otherwise stated, the acrylic block copolymers used in the embodiments were purchased from DuPont, model VMX3020.

[0038] In this invention, unless otherwise stated, the rubber used in the embodiments is purchased from Kronen, model FG1924.

[0039] Example 1

[0040] Reference Figure 1 As shown, this embodiment provides a laminated film for wafer backside polishing, including a release layer 1, an ultraviolet-cured anti-adhesion layer 2, a first buffer layer 3, a first substrate layer 4, a second buffer layer 5, a second substrate layer 6, and a third buffer layer 7 arranged sequentially from bottom to top;

[0041] Specifically, the following steps are included:

[0042] Release layer 1 is a PET release film with a thickness of approximately 30μm and a release force of approximately 30gf / 25mm.

[0043] The peel strength of the UV-cured anti-tack layer 2 after UV irradiation is approximately 20gf / 25mm;

[0044] The first buffer layer 3 is made of acrylic resin and has a thickness of approximately 100 μm.

[0045] The first substrate layer 4 is a polyethylene terephthalate (PET) film with a thickness of approximately 25 μm;

[0046] The second buffer layer 5 is made of rubber and has a thickness of approximately 100 μm.

[0047] The second substrate layer 6 is a polyethylene terephthalate (PET) film with a thickness of approximately 25 μm;

[0048] The third buffer layer 7 is an acrylic block copolymer with a thickness of approximately 100 μm.

[0049] Example 2

[0050] Basically the same as in Embodiment 1, except that the materials of the second buffer layer 5 and the first buffer layer 3 are changed, as follows:

[0051] This embodiment provides a laminated film for wafer backside polishing, comprising, from bottom to top, a release layer 1, an ultraviolet-cured anti-adhesion layer 2, a first buffer layer 3, a first substrate layer 4, a second buffer layer 5, a second substrate layer 6, and a third buffer layer 7;

[0052] Specifically, the following steps are included:

[0053] Release layer 1 is a PET release film with a thickness of approximately 30μm and a release force of approximately 30gf / 25mm.

[0054] The peel strength of the UV-cured anti-tack layer 2 after UV irradiation is approximately 20gf / 25mm;

[0055] The first buffer layer 3 is made of rubber and has a thickness of approximately 100 μm;

[0056] The first substrate layer 4 is a polyethylene terephthalate (PET) film with a thickness of approximately 25 μm;

[0057] The second buffer layer 5 is made of acrylic resin and has a thickness of approximately 100 μm.

[0058] The second substrate layer 6 is a polyethylene terephthalate (PET) film with a thickness of approximately 25 μm;

[0059] The third buffer layer 7 is an acrylic block copolymer with a thickness of approximately 100 μm.

[0060] Example 3

[0061] Basically the same as in Example 1, except that the materials of the second buffer layer 5 and the second buffer layer 7 are changed, as follows:

[0062] This embodiment provides a laminated film for wafer backside polishing, comprising, from bottom to top, a release layer 1, an ultraviolet-cured anti-adhesion layer 2, a first buffer layer 3, a first substrate layer 4, a second buffer layer 5, a second substrate layer 6, and a third buffer layer 7;

[0063] Specifically, the following steps are included:

[0064] Release layer 1 is a PET release film with a thickness of approximately 30μm and a release force of approximately 30gf / 25mm.

[0065] The peel strength of the UV-cured anti-tack layer 2 after UV irradiation is approximately 20gf / 25mm;

[0066] The first buffer layer 3 is made of acrylic resin and has a thickness of approximately 100 μm.

[0067] The first substrate layer 4 is a polyethylene terephthalate (PET) film with a thickness of approximately 25 μm;

[0068] The second buffer layer 5 is an acrylic block copolymer with a thickness of approximately 100 μm;

[0069] The second substrate layer 6 is a polyethylene terephthalate (PET) film with a thickness of approximately 25 μm;

[0070] The third buffer layer 7 is made of rubber and has a thickness of approximately 100 μm.

[0071] Example 4

[0072] Basically the same as Example 1, except that the thickness of the second buffer layer 5 is adjusted to 150 μm, as follows:

[0073] This embodiment provides a laminated film for wafer backside polishing, comprising, from bottom to top, a release layer 1, an ultraviolet-cured anti-adhesion layer 2, a first buffer layer 3, a first substrate layer 4, a second buffer layer 5, a second substrate layer 6, and a third buffer layer 7;

[0074] Specifically, the following steps are included:

[0075] Release layer 1 is a PET release film with a thickness of approximately 30μm and a release force of approximately 30gf / 25mm.

[0076] The peel strength of the UV-cured anti-tack layer 2 after UV irradiation is approximately 20gf / 25mm;

[0077] The first buffer layer 3 is made of acrylic resin and has a thickness of approximately 100 μm.

[0078] The first substrate layer 4 is a polyethylene terephthalate (PET) film with a thickness of approximately 25 μm;

[0079] The second buffer layer 5 is made of rubber and has a thickness of approximately 150 μm.

[0080] The second substrate layer 6 is a polyethylene terephthalate (PET) film with a thickness of approximately 25 μm;

[0081] The third buffer layer 7 is an acrylic block copolymer with a thickness of approximately 100 μm.

[0082] Comparative Example 1

[0083] It is basically the same as Example 1, except that the first buffer layer 3 is not set.

[0084] Comparative Example 2

[0085] It is basically the same as Example 1, except that a second buffer layer 5 is not provided.

[0086] Comparative Example 3

[0087] It is basically the same as Example 1, except that a third buffer layer 7 is not provided.

[0088] Comparative Example 4

[0089] It is basically the same as Example 1, except that the material of the second buffer layer 5 is replaced with the material of the first buffer layer 3, which is an acrylic resin.

[0090] Test case

[0091] The peel strength, embedding properties, and other properties of the laminated films used for wafer backside polishing in Examples 1-4 and Comparative Examples 1-4 were tested:

[0092] 180° peel strength (gf / 25mm): Determined according to the standard of GB / T 2792-2014 "Test method for peel strength of adhesive tapes";

[0093] Embedding properties (μm): The laminated film is attached to the surface of the bump wafer, pressed with a pressure of 0.2 MPa for 10 seconds, the laminated film is peeled off, and the depth of the depression is tested;

[0094] Residual adhesive test: The laminated film is attached to the surface of the bump wafer, pressed with a pressure of 0.2MPa for 10s, placed at 60℃ for 48h, and then the laminated film is peeled off. The wafer surface is then observed for any residual adhesive.

[0095] Table 1 shows the relevant test results:

[0096] Table 1

[0097] Sample 180° peel force of steel plate 180° peel force for wafers Embedding Residual adhesive Example 1 1500 1300 54 none Example 2 1460 1280 52 none Example 3 1450 1270 53 none Example 4 1380 1340 60 none Comparative Example 1 1180 1090 41 none Comparative Example 2 1200 930 32 none Comparative Example 3 1160 1080 40 none Comparative Example 4 1250 1100 42 none

[0098] As shown in Table 1, the laminated films of the embodiments exhibit good adhesion to the steel plate and wafer surface, excellent embedding properties for bump wafers, and no residue was observed in the accelerated aging residue test. Examples 1-3 show that placing the rubber in the middle results in a better embedding depth; this is because when the rubber is in the first buffer layer, its greater elasticity and hardness make embedding the bump slightly more difficult; similarly, when the rubber is on the surface, after compression deformation, its high elasticity and high compressive rebound force gradually reduce the embedding depth. Relatively speaking, placing the rubber in the middle yields better results. Examples 1 and 4 show that increasing the thickness of the buffer layer can increase the embedding depth of the bump to a certain extent.

[0099] Compared with Example 1, Comparative Examples 1-3, which do not have three buffer layers, can significantly reduce the embedment depth.

[0100] Compared to Example 1, Comparative Example 4, which replaced two of its buffer layers with the same material, also significantly reduced the embedment depth.

[0101] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A laminated film for back-side grinding of a wafer, characterized in that, The wafer backside polishing laminate includes a release layer, an ultraviolet-cured anti-adhesion layer, a first buffer layer, a first substrate layer, a second buffer layer, a second substrate layer, and a third buffer layer arranged sequentially; the materials of the first buffer layer, the second buffer layer, and the third buffer layer are all different.

2. The laminated film for wafer backside polishing according to claim 1, characterized in that, The release layer is selected from release film or release paper.

3. The laminated film for wafer backside polishing according to claim 2, characterized in that, The thickness of the release film is 25μm-100μm, and the release force is 15gf / 25mm-150gf / 25mm.

4. The laminated film for wafer backside polishing according to claim 2, characterized in that, The release paper has a basis weight of 40 g / m³. 2 -80g / m 2 The release force is 15gf / 25mm-150gf / 25mm.

5. The laminated film for wafer backside polishing according to claim 1, characterized in that, The thicknesses of the first buffer layer, the second buffer layer, and the third buffer layer are independently 10 μm-500 μm.

6. The laminated film for wafer backside polishing according to claim 1, characterized in that, The UV-cured anti-adhesion layer has a peel strength of 5gf / 25mm-100gf / 25mm after UV irradiation.

7. The laminated film for wafer backside polishing according to claim 1, characterized in that, The thickness of the UV-curable anti-adhesion layer is 5μm-50μm.

8. The laminated film for wafer backside polishing according to claim 1, characterized in that, The first substrate layer and the second substrate layer are independently selected from polyethylene terephthalate film, polyolefin film, polypropylene film, polyethylene film, polyimide film, polyethylene naphthalate film or polyamide-imide film.

9. The laminated film for wafer backside polishing according to claim 1, characterized in that, The thickness of the first substrate layer and the second substrate layer are independently 20μm-100μm.

Images