Silver-plated frame for preventing crystal grain adhesive from overflowing and packaging structure formed by silver-plated frame

Abstract

The utility model provides a silver-plated frame for preventing crystal grain adhesive from overflowing and a packaging structure formed by the silver-plated frame, and belongs to the technical field of semiconductor packaging, the silver-plated frame comprises a group of frame units arranged according to a design rule, each frame unit comprises a frame substrate, and the surface of each frame substrate comprises a silver-plated area and a bare copper area. The bare copper area is located in the middle of the surface of the frame substrate, and the silver-plated area is located around the bare copper area; a circle of annular lug boss is arranged on the bare copper area; the annular lug boss is a copper ring generated in an electroplating mode; according to the invention, the annular projection part is arranged on the bare copper area, so that the liquid crystal grain adhesive can be effectively prevented from diffusing to the silver plating area.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor packaging, and in particular to a silver-plated frame for preventing chip adhesive from overflowing and a packaging structure composed of the frame. Background Art

[0002] During the electrical connection between the chip and the frame, the corresponding welding area of ​​the frame will be silver-plated; the actual silver-plated thickness of the silver-plated frame used for chip packaging is generally 1.8~4um; the thickness of the grain paste used in chip packaging is generally 8-40um, which is much higher than the silver-plated thickness of the frame; during the grain paste operation, the grain paste is liquid and has a certain fluidity; when the grain paste on the frame surface overflows to the edge of the silver-plated area, the silver-plated area will be contaminated, which will make it impossible to weld wires in the silver-plated area of ​​the frame, and the chip will not be able to complete the external electrical connection

[0003] At present, the main way to prevent the diffusion of die-bonding glue on silver-plated frames is to post-treat the frames with anti-diffusion agents; however, the treatment effect of the anti-diffusion agents cannot be detected by equipment, and the anti-overflow quality is difficult to monitor; that is, the effect of preventing the overflow of die-bonding glue obtained by surface treatment methods cannot be monitored and guaranteed. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to address the deficiencies in the prior art and provide a silver-plated frame and a packaging structure composed of the frame to prevent the overflow of the die paste glue. By establishing an annular protrusion on the bare copper area, the liquid die paste glue can be effectively prevented from diffusing to the silver-plated area.

[0005] Technical solution: The silver-plated frame of the present invention prevents the overflow of the die paste glue, and the silver-plated frame includes a group of frame units arranged according to the design rules, and the frame units include a frame substrate, and the surface of the frame substrate includes a silver-plated area and a bare copper area, the bare copper area is located in the middle of the surface of the frame substrate, and the silver-plated area is located around the bare copper area; a circle of annular protrusions is arranged on the bare copper area. The front view of the protruding copper ring can be a rectangle or any closed shape designed to meet the application requirements, and the height of the protruding part must be kept consistent to prevent side leakage; the cross-section of any position of the plated copper ring is a regular rectangle.

[0006] Furthermore, the annular protrusion is a copper ring generated by electroplating.

[0007] Furthermore, the height of the annular protrusion ranges from 10 to 100 μm.

[0008] Furthermore, the width of the annular protrusion is in the range of 1 / 4 to 1 / 2 of the height of the annular protrusion.

[0009] Furthermore, the distance between the annular protrusion and the silver-plated area is twice the height of the annular protrusion.

[0010] Furthermore, the silver-plated area includes a silver-plated edge surrounding the bare copper area.

[0011] A packaging structure including a silver-plated frame for preventing overflow of a die-bonding adhesive comprises a chip, a die-bonding film, a wire and a plastic seal; a chip is mounted in the middle of the silver-plated frame, a die-bonding film formed by the die-bonding adhesive is arranged between the chip and the frame substrate, the chip is connected to the silver-plated area via the wire, and the plastic seal seals the chip and the lead frame.

[0012] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0013] (1) The present invention can effectively prevent the liquid die paste from overflowing into the silver-plated area by establishing an annular protrusion on the bare copper area;

[0014] (2) The annular protrusion provided in the present invention is a copper ring generated by electroplating, which can ensure the flatness of the frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the silver-plated frame in the present invention;

[0016] Figure 2 It is a structural schematic diagram of the packaging structure in the present invention;

[0017] Figure 3 It is a preparation flow chart of the silver-plated frame in the present invention. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0019] Example 1

[0020] like Figure 1 A silver-plated frame for preventing the overflow of die paste glue is shown, the silver-plated frame includes a group of frame units arranged according to the design rules, the frame unit includes a frame substrate 1, the surface of the frame substrate 1 includes a silver-plated area 2 and a bare copper area 3, the silver-plated area 2 includes a silver-plated edge surrounding the bare copper area 3, the bare copper area 3 is located in the middle of the surface of the frame substrate 1, and the silver-plated area 2 is located around the bare copper area 3; a circle of annular protrusions 4 is arranged on the bare copper area 3. The annular protrusion 4 is a copper ring generated by electroplating. The height of the annular protrusion 4 is 40μm; the width of the annular protrusion 4 is 1 / 4~1 / 2 of the height of the annular protrusion; the distance between the annular protrusion 4 and the silver-plated area 2 is twice the height of the annular protrusion.

[0021] Example 2

[0022] like Figure 2 The package structure shown includes a silver-plated frame for preventing the overflow of the die-bonding glue, including a chip 5, a die-bonding film 6, a wire 7 and a plastic seal 8; the chip 5 is installed in the middle of the silver-plated frame, a die-bonding film 6 formed by the die-bonding glue is arranged between the chip 5 and the frame substrate 1, the chip 5 is connected to the silver-plated area 2 through the wire 7, and the plastic seal 8 seals the chip 5 and the lead frame. The silver-plated frame has the same structure as that of Example 1.

[0023] Example 3

[0024] like Figure 3 As shown, the process flow of this embodiment is as follows:

[0025] The raw materials are pre-cleaned, pressed, exposed to X-rays, cleaned and developed, and the copper material of the uncovered dry film is etched away by chemical solution to obtain the desired shape. Then, after a second press of the photosensitive dry film, X-ray exposure, cleaning and development, a silver layer is plated on the uncovered dry film by electroplating. Finally, after a third press of the photosensitive dry film, X-ray exposure, cleaning and development, a copper ring is plated on the uncovered dry film by electroplating.

[0026] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A silver-plated frame for preventing die paste from overflowing, the silver-plated frame comprising a group of frame units arranged according to design rules, characterized in that: The frame unit comprises a frame substrate (1), the surface of the frame substrate (1) comprises a silver-plated area (2) and a bare copper area (3), the bare copper area (3) is located in the middle of the surface of the frame substrate (1), and the silver-plated area (2) is located around the bare copper area (3); A circle of annular protrusions (4) is provided on the bare copper area (3).

2. A silver-plated frame for preventing chip paste from overflowing according to claim 1, characterized in that: The annular raised portion (4) is a copper ring produced by electroplating.

3. A silver-plated frame for preventing chip paste glue from overflowing according to claim 1 or 2, characterized in that: The height of the annular protrusion (4) ranges from 10 to 100 μm.

4. A silver-plated frame for preventing chip adhesive from overflowing according to claim 1 or 2, characterized in that: The width of the annular protrusion (4) is in the range of 1 / 4 to 1 / 2 of the height of the annular protrusion.

5. A silver-plated frame for preventing chip paste from overflowing according to claim 1 or 2, characterized in that: The distance between the annular protrusion (4) and the silver-plated area (2) is twice the height of the annular protrusion.

6. The silver-plated frame for preventing chip paste from overflowing according to claim 5, characterized in that: The silver-plated area (2) comprises a silver-plated edge surrounding the bare copper area (3).

7. A packaging structure comprising a silver-plated frame for preventing die-bonding adhesive from overflowing as claimed in any one of claims 1 to 6, characterized in that: The invention comprises a chip (5), a grain pasting film (6), a wire (7) and a plastic seal (8); the chip (5) is mounted in the middle of the silver-plated frame, a grain pasting film (6) formed by a grain pasting glue is arranged between the chip (5) and the frame base material (1), the chip (5) is connected to the silver-plated area (2) via the wire (7), and the plastic seal (8) plastic-seals the chip (5) and the lead frame.

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