A chip structure for improving glue overflow and its exposed chip packaging structure

Abstract

The utility model discloses a chip structure for improving glue overflow and a bare chip packaging structure thereof, the chip structure for improving glue overflow comprises a chip body, a groove is provided around the effective area of ​​the chip body, an invalid area is reserved on the chip body outside the groove, and the groove is an annular closed groove or a non-closed groove; the bare chip packaging structure comprises a substrate, and a chip structure for improving glue overflow arranged on the substrate, the side of the chip body facing away from the substrate is an exposed end, the groove is located at the exposed end, the exposed end is covered with a release film, a space for plastic encapsulation material to be filled is formed between the release film and the substrate, the plastic encapsulation material is filled into the substrate surface and around the chip body, a small amount of plastic encapsulation material overflows the invalid area through the gap between the release film and the exposed end of the chip body to fill the groove, and the effective area is not covered with plastic encapsulation material. The chip structure with pre-opened grooves provided by the utility model is divided into an effective area and an invalid area, and is applied to a bare chip packaging structure to improve the poor glue overflow on the chip surface.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor packaging, and more particularly to a chip structure for improving glue overflow and a bare chip packaging structure thereof. Background Art

[0002] To ensure high heat dissipation from the chip surface, some products require bare chip packaging to facilitate heat dissipation. During the packaging process for bare chip products, a release film is typically used as an insulating material to separate the chip from the mold. This soft material protects the chip while also preventing plastic encapsulation compound from overflowing onto the chip surface.

[0003] Due to the high injection pressure, the plastic compound easily penetrates into the gap between the chip and the release film, making it easy for the plastic to overflow at the edge of the chip, thus causing product defects. If the injection pressure is reduced, the product will have defects such as internal voids. Utility Model Content

[0004] In order to solve the above problems, the present invention provides a novel chip structure, which is applied to a bare chip packaging structure, can improve the glue overflow defect on the chip surface and improve the yield rate of the packaged product.

[0005] According to one aspect of the present invention, a chip structure for improving glue overflow is provided, comprising a chip body, wherein a groove is provided around an active area of ​​the chip body, and an inactive area is reserved on the chip body outside the groove. The groove is used to fill the molding compound that overflows the inactive area to prevent the molding compound from flowing into the active area. Thus, during the injection molding process, a small amount of molding compound overflows the inactive area outside the groove and flows into the groove. Since the inactive area blocks the high pressure during the injection molding process, the molding compound is no longer subjected to the high pressure of the injection molding process after flowing into the groove. Therefore, the molding compound in the groove will not flow into the active area of ​​the chip body, thereby keeping the active area of ​​the chip body clean.

[0006] In some embodiments, the width of the groove is 20-300 μm, the depth of the groove is 10-100 μm, and the width of the inactive area is 50-300 μm. Thus, the width of the inactive area outside the groove is retained to increase the high pressure resistance of the inactive area during the injection molding process.

[0007] In some embodiments, the groove is an annular closed groove. Thus, the annular closed groove can be processed outside the active area of ​​the chip body by laser grooving.

[0008] In some embodiments, the groove is a non-enclosed groove, which is composed of four grooves that intersect vertically and horizontally, and the active area of ​​the chip body is located in the middle of the four grooves. Therefore, the four grooves can be processed by cutting to form a non-enclosed groove outside the active area of ​​the chip body.

[0009] According to another aspect of the present invention, a bare chip packaging structure is provided, which includes a substrate, a metal circuit layer inside the substrate, a metal pad on the front of the substrate, and the above-mentioned chip structure with improved glue overflow on the substrate. The side of the chip body facing away from the substrate is an exposed end, and the groove is located at the exposed end of the chip body. The exposed end of the chip body is covered with a release film, and a space for plastic encapsulation material to be filled is formed between the release film and the substrate. The plastic encapsulation material is filled into the surface of the substrate and around the chip body. A small amount of plastic encapsulation material overflows the invalid area through the gap between the release film and the exposed end of the chip body to fill the groove. The effective area of ​​the exposed end of the chip body is not covered with plastic encapsulation material.

[0010] Therefore, grooves are pre-machined on the surface of the chip body, and the chip body is mounted on the substrate. Depending on the design requirements, some products will be filled with bottom filler at the bottom of the chip body. Then, the product is placed in the injection mold. A release film is installed on the side of the mold close to the groove of the chip body. The release film is adsorbed on the mold surface by vacuum. After the product and the molding compound are ready, the mold is closed, and the melted molding compound slowly fills into the substrate surface and around the chip body. As the pressure increases, a small amount of resin in the molding compound will enter the gap between the release film and the chip body and flow into the groove. Because the pressure on the groove is very small, this part of the resin will not continue to overflow to the surface of the active area of ​​the chip. After the molding compound solidifies, the upper and lower molds are separated. A small amount of resin will remain in the groove of the chip body, while the surface of the active area of ​​the chip body remains clean.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a new chip structure with a simple structure. By opening grooves on the periphery of the effective area on the surface of the chip body and distinguishing the invalid area, the new chip structure is applied to the exposed chip packaging structure. After the chip body is mounted on the substrate, the surrounding area of ​​the chip body and the surface of the substrate are injection-molded with plastic encapsulation material. During the injection molding process, as the pressure increases, a small amount of resin in the plastic encapsulation material will enter the gap between the release film and the chip body, overflow the invalid area and flow into the groove. Since the invalid area will block the high pressure during the injection molding process, the plastic encapsulation material will no longer be subjected to the injection molding high pressure after flowing into the groove, and this part of the resin will not continue to overflow to the surface of the effective area of ​​the chip. In this way, the glue overflow problem on the chip surface can be improved and the yield rate of the packaged product can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic structural diagram of an embodiment of a chip structure for improving glue overflow using a closed groove according to the present invention, wherein: Figure 1 A is the main view of the chip structure. Figure 1 B is a top view of the chip structure;

[0013] Figure 2This is a schematic structural diagram of an embodiment of a chip structure for improving glue overflow using a non-enclosed groove according to the present invention, wherein: Figure 2 A is the main view of the chip structure. Figure 2 B is a top view of the chip structure;

[0014] Figure 3 This is a schematic diagram of a plastic encapsulation process of an embodiment of a bare chip packaging structure of the present invention;

[0015] Figure 4 It is a structural schematic diagram of an embodiment of a bare chip packaging structure of the present invention. DETAILED DESCRIPTION

[0016] The present invention will be further described below in conjunction with specific implementation methods.

[0017] Example 1

[0018] like Figure 1 and 2 As shown, an embodiment of the present invention provides a chip structure for improving glue overflow. The chip structure includes a chip body 1, a groove 13 formed around an active area 11 of the chip body 1, and an inactive area 12 reserved on the chip body 1 outside the groove 13. The groove 13 is used to fill the plastic encapsulation compound that overflows the inactive area 12 to prevent the plastic encapsulation compound from flowing into the active area 11. The front surface of the chip body 1 can be a metal bump.

[0019] The width W1 of the groove 13 is 20 to 300 μm, and the depth H of the groove 13 is 10 to 100 μm. The width W2 of the retained inactive area 12 is 50 to 300 μm, ensuring that the inactive area 12 outside the groove 13 has a certain width, which can increase the inactive area 12's resistance to high pressure during the injection molding process.

[0020] In practical applications, an annular closed groove can be processed outside the active area 11 of the chip body 1 by laser grooving, such as Figure 1 shown.

[0021] The groove 13 can also be a non-closed groove. By cutting and grooving, four grooves 13 are processed. The four grooves 13 are perpendicular to each other and cross each other vertically and horizontally. The effective area 11 of the chip body 1 is surrounded by the middle of the four grooves 13. In this way, four non-closed grooves 13 are formed. Figure 2 shown.

[0022] During the injection molding process, a small amount of molding compound overflows the ineffective area 12 on the outer circle of the groove 13 and flows into the groove 13. Since the ineffective area 12 blocks the high pressure during the injection molding process, the molding compound is no longer subjected to the injection high pressure after flowing into the groove 13. Therefore, the molding compound in the groove 13 will not flow into the effective area 11 of the chip body 1, so that the effective area 11 of the chip body 1 remains clean.

[0023] Example 2

[0024] like Figure 3 and 4 As shown, another embodiment of the present invention is an exposed chip packaging structure, which includes a substrate 2 and the above-mentioned chip structure with improved glue overflow arranged on the substrate 2, the substrate 2 has a metal circuit layer inside, the substrate 2 has a metal pad on the front, the side of the chip body 1 facing away from the substrate 2 is an exposed end 10, the groove 13 is located at the exposed end 10 of the chip body 1, and the surface of the substrate 2 and the surrounding of the chip body 1 are sealed with plastic encapsulation material 3.

[0025] The plastic encapsulation process of the exposed chip packaging structure is as follows: prepare a substrate 2 and a pre-grooved chip body 1; there is a metal pad on the front of the substrate 2, and the distribution of the metal pads of the substrate 2 matches the distribution of the bumps on the front of the chip, and the pre-grooved chip body 1 is mounted on the substrate 2. According to design requirements, some products will fill the bottom of the chip with bottom filling glue; put the product into an injection mold (not shown), and a release film 4 is installed on the side of the mold close to the groove 13 of the chip body 1. The release film 4 is adsorbed on the mold surface by vacuum. After the product and the plastic encapsulation material are ready, the mold is closed; after the mold is closed, the release film 4 covers the exposed end 10 of the chip body 1. A space for the molding compound 3 to be filled is formed between the release film 4 and the substrate 2. The melted molding compound 3 slowly fills into the surface of the substrate 2 and around the chip body 1. As the pressure increases, a small amount of resin in the molding compound will enter the gap between the release film 4 and the exposed end 10 of the chip body 1, overflow over the inactive area 12, and flow into the groove 13. Since the pressure on the groove 13 is very small, this part of the resin will not continue to overflow to the surface of the chip active area 11. After the molding compound 3 is solidified, the upper and lower molds are separated. A small amount of resin will remain in the groove 13 of the chip body 1, and the surface of the active area 11 of the exposed end 10 of the chip body 1 will be free of molding compound and remain clean.

[0026] The present utility model provides a novel chip structure with a simple structure. By opening a groove 13 on the periphery of an effective area 11 on the surface of a chip body 1 and distinguishing an ineffective area 12, the novel chip structure is applied to a bare chip packaging structure. After the chip body 1 is mounted on a substrate 2, the periphery of the chip body 1 and the surface of the substrate 2 are injection-molded and filled with plastic encapsulation material. During the injection molding process, as the pressure increases, a small amount of resin in the plastic encapsulation material will enter the gap between the release film 4 and the chip body 1, overflow over the ineffective area 12 and flow into the groove 13. Since the ineffective area 12 will block the high pressure during the injection molding process, the plastic encapsulation material will no longer be subjected to the injection molding high pressure after flowing into the groove 13, and this part of the resin will not continue to overflow to the surface of the chip effective area 11. In this way, the glue overflow problem on the chip surface can be improved, and the yield rate of the packaged product can be improved.

[0027] The above are only some embodiments of the present invention. It should be pointed out that for ordinary technicians in this field, other variations and improvements can be made without departing from the creative concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A chip structure for improving glue overflow, comprising a chip body (1), characterized in that: A groove (13) is provided around the effective area (11) of the chip body (1), an ineffective area (12) is reserved on the chip body (1) outside the groove (13), and the groove (13) is used to fill the molding compound that overflows the ineffective area (12) to prevent the molding compound from flowing into the effective area (11).

2. The chip structure for improving glue overflow according to claim 1, characterized in that: The width of the groove (13) is 20 to 300 μm, the depth of the groove (13) is 10 to 100 μm, and the width of the ineffective area (12) is 50 to 300 μm.

3. The chip structure for improving glue overflow according to claim 2, characterized in that: The groove (13) is an annular closed groove.

4. The chip structure for improving glue overflow according to claim 2, characterized in that: The groove (13) is a non-closed groove, which is composed of four grooves that cross each other vertically and horizontally, and the effective area (11) of the chip body (1) is located in the middle of the four grooves.

5. A bare chip packaging structure, comprising a substrate (2), wherein the substrate (2) has a metal circuit layer inside, and the front surface of the substrate (2) has a metal pad, characterized in that: The substrate (2) has a chip structure for improving glue overflow as claimed in any one of claims 1 to 4, the side of the chip body (1) facing away from the substrate (2) is an exposed end (10), the groove (13) is located at the exposed end (10) of the chip body (1), the exposed end (10) of the chip body (1) is covered with a release film (4), a space for filling with a plastic encapsulation material (3) is formed between the release film (4) and the substrate (2), the plastic encapsulation material (3) is filled into the surface of the substrate (2) and around the chip body (1), a small amount of plastic encapsulation material overflows through the gap between the release film (4) and the exposed end (10) of the chip body (1) and fills the groove (13), and the effective area (11) of the exposed end (10) of the chip body (1) is not covered with plastic encapsulation material.

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