Sidewall bonding pad type ceramic packaging structure

Abstract

The utility model discloses a side wall bonding pad type ceramic packaging structure, which comprises a ceramic shell base, a lead frame, a sealing ring, a metal cover plate and a chip, the chip is arranged in a core cavity of the ceramic shell base, and side wall bonding pads directly facing the leading-out terminal bonding pads of the chip one by one are arranged on the inner side wall of the core cavity and are connected with the leading-out terminal bonding pads through eutectic bonding; the side wall bonding pads are correspondingly connected with the bonding pads on the bottom face of the ceramic shell base through an internal circuit of the ceramic shell base. The pins on the lead frame located on the outer side of the ceramic shell base are connected with the bonding pads on the bottom face of the ceramic shell base in a one-to-one correspondence mode. And the top of the ceramic shell base is connected with the metal cover plate through a sealing ring. In the structure, the bonding pads at the leading-out ends of the chip and the bonding pads on the side wall of the core cavity form a stable connection structure through the eutectic bonding technology, and compared with an existing structure adopting bonding wires, the risk of open circuit can be reduced, so that the stability and the reliability of packaging are improved.

Description

Technical Field

[0001] The utility model relates to a chip packaging structure, in particular to a ceramic packaging structure. Background Art

[0002] Ceramic packaging shells are widely used in device packaging such as hybrid integrated circuits, optoelectronic devices, surface acoustic wave devices, Hall devices, crystal oscillators and solid-state relays due to their high air tightness, high thermal conductivity, high moisture resistance, high mechanical strength, and high insulation resistance. Ceramic packaging shells have good reliability, and surface mount shells produced using multi-layer ceramic technology are suitable for mass production. They have a good performance-price ratio and are widely used in communications, industrial lasers, consumer electronics, automotive electronics and other fields.

[0003] Multilayer ceramic shells are generally made by adding ceramic powder to organic binders and solvents through rolling, extrusion or casting to form a ceramic raw film of a certain thickness, which is then punched / cavitated, printed with metal paste for wiring, laminated, hot cut and sintered into a ceramic matrix. After the ceramic matrix is ​​nickel plated, it is assembled and brazed, and then electroplated with nickel and gold before it can be inspected and delivered. The main raw materials involved in production are multilayer ceramic materials, printing paste, lead frames, sealing ring materials, heat sink materials and solder.

[0004] In the traditional ceramic packaging structure, the sintered ceramic matrix prepared in the above process is a step-type structure, which is assembled and brazed into a cavity structure to accommodate the chip. The bonding finger pattern is printed on the step inside the cavity, and the chip and the bonding finger pattern are bonded one by one with bonding wire (gold wire or silicon aluminum wire). If the bonding process is unstable, foreign matter such as gold-aluminum compounds is easily generated, or the bonding process is not accurate enough, resulting in the bonding wire being debonded, causing the circuit to be broken. Summary of the invention

[0005] Purpose of the invention: In view of the above-mentioned prior art, a sidewall pad type ceramic packaging structure is proposed to solve the problem of poor connection reliability caused by the existing bonding.

[0006] Technical solution: A side wall pad type ceramic packaging structure, comprising a ceramic shell base, a lead frame, a sealing ring, a metal cover plate and a chip; the chip is arranged in a core cavity of the ceramic shell base, and the inner side wall of the core cavity is provided with side wall pads that are directly opposite to each lead end pad of the chip, and are connected to each lead end pad through eutectic welding; the side wall pads are respectively connected to the pads on the bottom surface of the ceramic shell base through the internal circuit of the ceramic shell base, and each pin on the lead frame located outside the ceramic shell base is connected to the pads on the bottom surface of the ceramic shell base one by one; the top of the ceramic shell base is connected to the metal cover plate through a sealing ring.

[0007] Furthermore, a metallized portion is provided on the bottom surface of the core cavity, facing each of the side wall pads one by one.

[0008] Furthermore, the lower end of the side wall pad is connected to the metallized portion facing it.

[0009] Beneficial effects: The utility model improves the existing ceramic packaging structure. The core cavity of the ceramic shell base does not need to be designed with a step structure. Instead, a side wall pad is pre-prepared on the side wall of the core cavity. The side wall pad is connected to the pad on the bottom of the ceramic shell base through the internal circuit of the ceramic shell base, and then connected to the lead frame. In this structure, the pads of each lead end of the chip form a stable connection structure with the pads on the side wall of the core cavity through the eutectic welding process. Compared with the existing structure using bonding wires, it can reduce the risk of circuit breaking, thereby improving the stability and reliability of the package.

[0010] In addition, a metallized portion is provided on the bottom surface of the core cavity, facing each side wall pad one by one, for depositing solder during eutectic welding, which can further enhance the welding firmness.

[0011] Compared with the prior art, the ceramic housing base of this structure does not require steps, so the package size and weight can be reduced, which is convenient for optimizing circuit board design and installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the top view of the ceramic packaging structure of the utility model;

[0013] Figure 2 yes Figure 1 Schematic diagram of the longitudinal half-section structure;

[0014] Figure 3 This is a schematic diagram of the top view of the ceramic packaging structure of the utility model after removing the metal cover plate and the chip;

[0015] Figure 4 This is a schematic diagram of the bottom view of the ceramic packaging structure of the utility model;

[0016] Figure 5 yes Figure 3 Schematic diagram of the longitudinal half-section structure;

[0017] Figure 6 yes Figure 3 Schematic diagram of the transverse half-section structure. DETAILED DESCRIPTION

[0018] The utility model is further explained below in conjunction with the accompanying drawings.

[0019] A sidewall pad type ceramic packaging structure includes a ceramic shell base 1, a lead frame 2, a sealing ring 3, a metal cover plate 4 and a chip 5. The top of the ceramic shell base 1 is open, and the interior is a core cavity. The ceramic shell base 1 is generally made of alumina material. The chip 5 is arranged in the core cavity of the ceramic shell base 1. The inner side wall of the core cavity is provided with a sidewall pad 1-1 that is directly opposite to each lead-out terminal pad of the chip 5. The sidewall pad 1-1 is connected to each lead-out terminal pad through eutectic welding. The sidewall pad 1-1 is respectively connected to the pad 1-2 on the bottom surface of the ceramic shell base 1 through the internal circuit of the ceramic shell base 1, and each pin 2-1 on the lead frame 2 located outside the ceramic shell base 1 is connected to the pad 1-2 on the bottom surface of the ceramic shell base 1 one by one. The top of the ceramic shell base 1 is connected to the metal cover plate 4 through the sealing ring 3.

[0020] In this structure, a side wall pad 1-1 is provided on the side wall of the core cavity of the ceramic shell base 1. When installing the chip 5, the lead-out terminal pad of the chip 5 is aligned with the side wall pad 1-1 in the core cavity, and solder 6 is placed between the lead-out terminal pad and the side wall pad 1-1, and the eutectic welding process is used to form a reliable connection between the two.

[0021] Furthermore, the bottom surface of the core cavity is provided with metallized parts 1-3 facing each side wall pad 1-1, and the lower end of each side wall pad 1-1 is connected to the metallized parts 1-3 facing each side wall pad 1-1. The bottom of the core cavity has metallized parts 1-3 facing each side wall pad 1-1, which are used to accumulate solder during eutectic welding to enhance welding firmness.

[0022] It should be noted that since the side wall pad 1-1 and the metallized portion 1-3 are thin layers of metal paste printed, Figure 2 and Figure 5 Not shown in FIG.

[0023] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A sidewall pad type ceramic packaging structure, characterized in that: The invention comprises a ceramic housing base (1), a lead frame (2), a sealing ring (3), a metal cover plate (4) and a chip (5); the chip (5) is arranged in a core cavity of the ceramic housing base (1); the inner side wall of the core cavity is provided with side wall pads (1-1) which are directly opposite to the lead-out terminal pads of the chip (5) and are connected to the lead-out terminal pads by eutectic welding; the side wall pads (1-1) are respectively connected to the pads (1-2) on the bottom surface of the ceramic housing base (1) through the internal circuit of the ceramic housing base (1); the pins on the lead frame (2) located outside the ceramic housing base (1) are connected to the pads (1-2) on the bottom surface of the ceramic housing base (1) by one-to-one correspondence; the top of the ceramic housing base (1) is connected to the metal cover plate (4) through the sealing ring (3).

2. The sidewall pad type ceramic packaging structure according to claim 1, characterized in that: A metallized portion (1-3) facing each of the side wall pads (1-1) is provided on the bottom surface of the core cavity.

3. The sidewall pad type ceramic packaging structure according to claim 2, characterized in that: The lower end of the side wall pad (1-1) is connected to the metallized portion (1-3) facing it.

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