Taiko ring wafer removing cutting film reattaching method

Abstract

The application provides a Taiko ring removing wafer cutting film re-pasting method, which comprises the following steps: placing a wafer with a Taiko ring upside down; placing an interlayer paper and a wafer to be pasted on the wafer surface in sequence; performing a back surface film pasting process to paste a cutting film; performing UV exposure on the cutting film above the Taiko ring; and removing the wafer with the Taiko ring and the interlayer paper. The application completes the re-pasting of the cutting film by means of the wafer with the Taiko ring, solves the problem that the wafer with the Taiko ring cannot be pasted with the cutting film, and improves the wafer yield. Moreover, the method can be completed by using the existing wafer and equipment of the production line, and there is no cost problem and pollution risk problem of purchasing equipment.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and more specifically to a method for re-attaching the dicing film on a wafer after removing the Taiko ring. Background Technology

[0002] Taiko thinning technology is a new technology for back-side wafer grinding. Unlike previous back-side grinding techniques, this technology preserves the outer edge (approximately 3mm) of the wafer during grinding, thinning only the inner edge. By leaving an edge around the wafer's perimeter, wafer warpage is reduced, and wafer strength is enhanced.

[0003] 12-inch wafers typically use the Taiko thinning process for back-side thinning, resulting in a Taiko ring at the edge of the back side of the wafer after thinning. Figure 1 As shown, the Taiko ring provides support for the wafer. After the dicing film is applied to the wafer, the Taiko ring is removed, followed by wafer dicing and packaging. Wafers without Taiko rings rely on the dicing film for support and positioning, as shown in the diagram. Figure 2 As shown. In cases of abnormalities such as dicing film damage, the wafer cannot be diced and packaged. It is necessary to reapply the dicing film to the wafer after the Taiko ring has been removed. However, due to the large warpage of the wafer after removing the Taiko ring, such as... Figure 3 As shown, the inability to re-attach the dicing film prevents wafer dicing and packaging from being completed, leading to scrap in subsequent processes and resulting in yield loss. Summary of the Invention

[0004] In view of this, the present invention provides a method for re-attaching the dicing film on a wafer after removing the Taiko ring, in order to solve the problem of difficulty in re-attaching the wafer after removing the Taiko ring in the existing method.

[0005] This invention provides a method for re-attaching the dicing film on a wafer after removing the Taiko ring, comprising the following steps:

[0006] Step 1: Place the wafer with the Taiko rings formed facing up;

[0007] Step 2: Place the interlayer paper and the wafer to be coated sequentially on the surface of the wafer;

[0008] Step 3: Perform the back-side film application process and attach the cut film;

[0009] Step 4: Expose the cut film located above the Taiko ring with UV light;

[0010] Step 5: Remove the wafer with the Taiko ring and the interlayer paper.

[0011] Preferably, in step one, the back side of the wafer is thinned to form a Taiko ring.

[0012] Preferably, in step two, the interlayer paper and the wafer to be laminated are placed between the Taiko rings.

[0013] Preferably, the inner diameter of the Taiko ring is 0.5 mm to 6 mm larger than the diameter of the wafer to be coated.

[0014] Preferably, the diameter of the interlayer paper is within ±5 mm of the diameter of the wafer to be coated.

[0015] Preferably, the thickness of the wafer with the Taiko ring formed in step one and the wafer to be coated in step two is 20um to 250um.

[0016] Preferably, the cutting membrane attached in step three extends beyond the Taiko ring.

[0017] Preferably, the UV exposure in step four is used to reduce the adhesion of the cut film.

[0018] Preferably, in step five, a ring-removal process is used to separate the wafer with the Taiko ring from the dicing film and allow the interlayer paper to fall off naturally.

[0019] This invention utilizes a wafer with a Taiko ring to complete the application of a dicing film. First, the wafer with the Taiko ring is placed with its back side facing up. Then, interlayer paper and the wafer to be coated are sequentially placed on the wafer surface. Next, a back-side coating process is performed to attach the dicing film. Then, the dicing film located above the Taiko ring is subjected to UV exposure. Finally, the wafer with the Taiko ring and the interlayer paper are removed. This solves the problem of existing Taiko ring removal methods where, in cases of dicing film damage or other abnormalities, the dicing film cannot be applied, leading to wafer scrap and inability to be diced and packaged. This improves wafer yield. Moreover, the method can be completed using existing wafers and equipment on the production line, eliminating the cost and pollution risks associated with purchasing equipment. Attached Figure Description

[0020] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0021] Figure 1 This is a schematic diagram showing the dicing film applied to a Taiko wafer.

[0022] Figure 2 This is a schematic diagram of the wafer after the Taiko ring has been removed;

[0023] Figure 3This diagram shows an abnormally damaged dicing film after the removal of the Taiko ring, resulting in a wafer without a dicing film.

[0024] Figure 4 The flowchart shown is a method for re-attaching the dicing film of a wafer by removing the Taiko ring according to an embodiment of the present invention.

[0025] Figures 5-8 The diagram shows the structural schematics of each step in the Taiko ring removal wafer dicing and re-attaching method according to an embodiment of the present invention. Detailed Implementation

[0026] The present invention is described below based on embodiments, but the invention is not limited to these embodiments. In the detailed description of the invention below, certain specific details are described in detail. Those skilled in the art will fully understand the invention even without these details. To avoid obscuring the essence of the invention, well-known methods, processes, flows, elements, and circuits are not described in detail.

[0027] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0028] Unless the context explicitly requires it, words such as "including" or "contains" throughout the application should be interpreted as including rather than exclusive or exhaustive; that is, meaning "including but not limited to".

[0029] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0030] Figure 4 The flowchart shown is a method for re-attaching the dicing film of a wafer by removing the Taiko ring according to an embodiment of the present invention. Figures 5-8 The diagram shows the structural schematics of each step in the Taiko ring removal wafer dicing and re-attaching method according to an embodiment of the present invention. Figure 4 As shown, the method for re-attaching the dicing film on a wafer by removing the Taiko ring according to an embodiment of the present invention includes the following steps:

[0031] Step 1: Place the wafer with the Taiko rings formed facing up.

[0032] In this embodiment of the invention, the wafer can be made of undoped single-crystal silicon, doped single-crystal silicon, silicon-on-insulator (SOI), etc. Before performing Taiko thinning on the back side of the wafer, the front side process is performed, which will not be described in detail here. Based on the thickness requirements and packaging conditions of the power device, the back side of the wafer is thinned to form a Taiko ring, thus reducing the wafer thickness.

[0033] Step 2: Place the interlayer paper and the wafer to be coated sequentially on the wafer surface.

[0034] like Figure 5 As shown in the embodiment of the invention, the wafer with the formed Taiko rings (wafer 2 in the figure) is placed with its back side facing upwards, and the interlayer paper and the wafer to be laminated (wafer 1 in the figure) are placed sequentially and positioned between the Taiko rings. The thickness of the wafer with the formed Taiko rings and the wafer to be laminated is 20µm to 250µm. The inner diameter of the Taiko rings is 0.5mm to 6mm larger than the diameter of the wafer to be laminated, and the diameter of the interlayer paper is within ±5mm of the diameter of the wafer to be laminated. In a preferred implementation, the inner diameter of the Taiko rings is 294mm, the diameter of the wafer to be laminated is 288mm, and the diameter of the interlayer paper is between 283mm and 293mm.

[0035] Step 3: Apply the backing film by attaching the cut film.

[0036] like Figure 6 As shown, the dicing film extends beyond the Taiko ring. As an example, a specific back-side lamination process can be implemented using an electrostatic chuck. The chuck in the upper cavity holds the dicing film, while the base in the lower cavity supports the Taiko wafer, interlayer paper, and the wafer to be laminated. With the upper and lower cavities closed, back-side lamination is performed using a back-pressure gas supply. Of course, other suitable methods can also be used.

[0037] Step 4: Expose the cut film located above the Taiko ring with UV light.

[0038] In this embodiment of the invention, the cut film located above the Taiko ring is subjected to UV exposure using a UV exposure device for 150 seconds. UV exposure reduces the adhesion of the cut film above the Taiko ring.

[0039] Step 5: Remove the wafer and interlayer paper containing the Taiko rings.

[0040] In this embodiment of the invention, a ring removal process is used to separate the wafer with the formed Taiko ring from the dicing film and allow the interlayer paper to fall off naturally, thereby obtaining a successfully coated Taiko ring-removed wafer.

[0041] The method of this invention first places the wafer with the Taiko ring formed on the back side facing up, then places the interlayer paper and the wafer to be coated on the wafer surface in sequence, then performs the back coating process to attach the dicing film, then exposes the dicing film above the Taiko ring with UV, and finally removes the wafer with the Taiko ring formed and the interlayer paper, thus obtaining a successfully coated Taiko ring removed wafer.

[0042] This invention utilizes wafers with formed Taiko rings to complete the application of dicing films, solving the problem that existing Taiko ring removal wafers cannot be diced and packaged due to the inability to apply dicing films in abnormal situations such as damaged dicing films, resulting in scrap. This improves wafer yield, and the method can be completed using existing wafers and equipment on the production line, eliminating the cost issues and pollution risks associated with purchasing equipment.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for re-attaching the dicing film on a wafer after removing the Taiko ring, characterized in that, Includes the following steps: Step 1: Place the wafer with the Taiko rings formed facing up; Step 2: Place the interlayer paper and the wafer to be coated sequentially on the surface of the wafer; Step 3: Perform the back-side film application process and attach the cut film; Step 4: Expose the cut film located above the Taiko ring with UV light; Step 5: Remove the wafer with the Taiko ring and the interlayer paper.

2. The method for re-attaching the dicing film on a wafer after removing the Taiko ring according to claim 1, characterized in that, In step one, the back side of the wafer is thinned to form a Taiko ring.

3. The method for re-attaching the dicing film on a wafer after removing the Taiko ring according to claim 1, characterized in that, In step two, the interlayer paper and the wafer to be laminated are placed between the Taiko rings.

4. The method for re-attaching the dicing film on a wafer after removing the Taiko ring according to claim 3, characterized in that, The inner diameter of the Taiko ring is 0.5 mm to 6 mm larger than the diameter of the wafer to be coated.

5. The method for re-attaching the dicing film on a wafer after removing the Taiko ring according to claim 4, characterized in that, The diameter of the interlayer paper is within ±5 mm of the diameter of the wafer to be coated.

6. The method for re-attaching the dicing film on a wafer after removing the Taiko ring according to claim 1, characterized in that, The thickness of the wafer with the Taiko ring formed in step one and the wafer to be coated in step two is 20um to 250um.

7. The method for re-attaching the dicing film on a wafer after removing the Taiko ring according to claim 1, characterized in that, The cutting membrane attached in step three extends beyond the Taiko ring.

8. The method for re-attaching the dicing film on a wafer after removing the Taiko ring according to claim 1, characterized in that, The UV exposure described in step four is used to reduce the adhesion of the cut film.

9. The method for re-attaching the dicing film on a wafer after removing the Taiko ring according to claim 1, characterized in that, In step five, a ring-removal process is used to separate the wafer with the Taiko ring from the dicing film and allow the interlayer paper to fall off naturally.

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