A chip placement method to improve the yield of thin chips

Abstract

The present invention discloses a patch method for improving the yield of thin chips, and the patch steps are as follows: (1) firstly, the front side of a dummy chip is pasted on a substrate using insulating glue, and the back side of the dummy chip has a DAF film; (2) then, a thin chip with a failed DAF film or without a DAF film is pasted on the DAF film on the back side of the dummy chip. In the patch method of the present invention, the DAF film on the back side of the dummy chip is good, which can solve the problem of uneven pasting and warping of thin chips due to failed DAF films or without DAF films in the existing patch method, thereby preventing the thin chip from cracking, so that the patch yield is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor packaging, and in particular relates to a chip mounting method for improving the yield of thin chips. Background Art

[0002] In the chip packaging process, there will be some thin chips, such as those below 50um. Due to long-term placement or improper storage conditions, the DAF film (a sticky film that softens and adheres at high temperatures) under the thin chip will fail, resulting in abnormalities when attaching the chip in the DB process. Because the DAF film of the thin chip fails, poor chip attachment will cause the chip to warp. At the same time, the DAF fails and loses moisture, resulting in pores inside, and the chip is not attached flat. In the plastic sealing process, due to the huge mold clamping pressure and injection molding pressure, die cracks will occur, affecting the yield. The second situation is that the thin chip has no DAF film. In the above two cases, the use of existing chip mounting technology will result in abnormal thin chip mounting and low chip mounting yield (existing technology mounting methods such as Figure 2 As shown), therefore, in view of the above situation, it is necessary to provide a special production method to solve this problem. Summary of the invention

[0003] The purpose of the present invention is to provide a chip bonding method for improving the yield of thin chips in response to the above problems. A layer of Dummy chip is added, and the back of the Dummy chip has a DAF film. This can solve the problem of uneven bonding and warping of thin chips due to failure of the DAF film or the absence of the DAF film in the existing chip bonding method.

[0004] The technical solution of the present invention is achieved in this way.

[0005] A chip mounting method for improving the yield of thin chips, characterized in that the chip mounting steps are as follows:

[0006] (1) First, the front side of the Dummy chip is attached to the substrate using insulating glue, and the back side of the Dummy chip is provided with a DAF film.

[0007] (2) Then stick a thin chip with an invalid DAF film or without a DAF film on the DAF film on the back of the Dummy chip.

[0008] Furthermore, the thickness ratio of the dummy chip to the thin chip is 2-4:1.

[0009] It adds a layer of Dummy chip on the basis of the normal patch technology of the prior art. The back of the Dummy chip has a DAF film. During the patch process, the side of the Dummy chip with the DAF film is reversely pasted, and the front side of the Dummy chip is pasted on the substrate. After the Dummy chip is pasted, a thin chip with an invalid DAF film or without a DAF film is pasted, thereby completing the entire patch process.

[0010] The beneficial effects of the present invention are as follows: the chip mounting method of the present invention adds a layer of Dummy chip, and the DAF film on the back of the Dummy chip is good, which can solve the problem of uneven mounting and warping of thin chips due to failure of the DAF film or no DAF film in the existing chip mounting method, thereby preventing the thin chip from cracking and effectively improving the chip mounting yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the product structure of the patch method of the present invention.

[0012] Figure 2 It is a schematic diagram of the product structure of the prior art patch method.

[0013] In the figure, 1. substrate, 2. thin chip, 3. DAF film, 4. Dummy chip, 5. insulating glue. DETAILED DESCRIPTION

[0014] The technical solution of the present invention is further described in detail below through embodiments and accompanying drawings.

[0015] like Figure 1 As shown, a chip mounting method for improving the yield of thin chips of the present invention, the chip mounting steps are as follows:

[0016] (1) First, the front side of the Dummy chip 4 is attached to the substrate 1 by using insulating glue 5, and the back side of the Dummy chip 4 is provided with a DAF film 3.

[0017] (2) Then, a thin chip 2 with an invalid DAF film or without a DAF film is attached to the DAF film 3 on the back of the dummy chip 4.

[0018] The thickness ratio of the dummy chip 4 to the thin chip 2 is 3:1.

[0019] On the basis of normal patch, a layer of Dummy chip 4 is added, and the back of Dummy chip 4 is also DAF film 3. During patch, the side of Dummy chip 4 with DAF film 3 is reversely pasted, and the front side of Dummy chip 4 is pasted on substrate 1, and is combined with substrate 1 by using insulating glue 5. After pasting Dummy chip 4, thin chip 2 with invalid DAF film or without DAF film is pasted, so as to complete the whole patch process.

[0020] Figure 2The figure shows the chip mounting method of the prior art, which is to directly use the DAF film 3 on the back of the thin chip 2 to stick on the substrate 1. However, due to long-term placement or improper storage conditions, the DAF film 3 under the thin chip 2 fails, resulting in the thin chip 2 not being properly attached, which will cause the thin chip 2 to warp. At the same time, the DAF film 3 loses moisture due to failure, and there are pores inside, so the thin chip 2 cannot be attached flat. In the plastic sealing process, due to the huge mold clamping pressure and injection molding pressure, die cracks are caused, which affects the chip mounting yield and also leads to the waste of the thin chip 2.

[0021] From the above comparison, the patch method of the present invention has a good DAF film 3 on the back of the Dummy chip 4, which can solve the problem of uneven pasting and warping of the thin chip 2 due to failure of the DAF film or no DAF film in the existing patch method, prevent the thin chip 2 from cracking, and effectively improve the yield. After test data analysis, the yield of the existing patch method is about 80%, while the yield can be increased to about 95% after adopting the patch method of the present invention.

[0022] The above are preferred embodiments of the present invention. It should be noted that a person skilled in the art may make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications are also considered to be within the protection scope of the present invention.

Claims

1. A chip mounting method for improving the yield of thin chips, characterized in that: The patch steps are as follows: (1) First, the front side of the Dummy chip is attached to the substrate using insulating glue, and the back side of the Dummy chip is provided with a DAF film; (2) The thin chip with the failed DAF film is then attached to the DAF film on the back of the Dummy chip. After the attachment, the failed DAF film of the thin chip contacts the DAF film on the back of the Dummy chip.

2. The method for improving the yield of thin chips according to claim 1, characterized in that: The thickness ratio of the dummy chip to the thin chip is 2-4:1.

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