Small-pitch lead connecting structure of ceramic shell

Abstract

The utility model discloses a small-pitch lead connecting structure of a ceramic shell. The small-pitch lead connecting structure comprises a ceramic shell base and a lead frame, the ceramic shell base is provided with at least one row of bonding pads used for being connected with lead pins on a lead frame in a one-to-one correspondence mode, the adjacent bonding pads are located on different horizontal planes, the elevation difference is larger than 0.2 mm, and the pitch is larger than or equal to 0.45 mm. And at least one of two adjacent lead pins on the lead frame is a bending lead pin and is welded on the corresponding bonding pad. According to the multi-pin ceramic packaging structure, the bonding pads on the base of the ceramic shell are arranged on the horizontal planes with different heights, the distance between the lead wires is increased through the elevation space, the insulation resistance between the lead wires is guaranteed through the design, meanwhile, the requirement for the extremely small pitch of the ceramic shell is met, and therefore the requirement for miniaturization of the multi-pin ceramic packaging structure is met.

Description

Technical Field

[0001] The utility model relates to a ceramic packaging structure, in particular to a ceramic shell lead connection 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] Based on development needs, integrated circuit products continue to move forward on the path of high density, miniaturization, and high reliability. This development has put forward further requirements for the miniaturization of the ceramic shell of the packaging structure. In the prior art, some packaging structures have a large number of pins, and in the prior art, the minimum pitch of the leads of the ceramic shell, that is, the minimum horizontal center spacing between adjacent pins is 0.65mm, which hinders the miniaturization of the ceramic packaging structure. If the minimum pitch is further reduced, the insulation resistance between adjacent pins will not be guaranteed. Summary of the invention

[0004] Purpose of the invention: In view of the above-mentioned prior art, a small-pitch lead connection structure of a ceramic housing is proposed to ensure the insulation characteristics between the pins while reducing the product pitch.

[0005] Technical solution: A ceramic shell small pitch lead connection structure, including a ceramic shell base, the ceramic shell base and a lead frame; the ceramic shell base is provided with at least one row of pads for one-to-one connection with each lead pin on the lead frame, adjacent pads are located on different horizontal planes, the elevation difference is greater than 0.2mm, and the pitch is greater than or equal to 0.45mm; at least one of two adjacent lead pins on the lead frame is a bent lead pin and is welded to the corresponding pad.

[0006] Furthermore, the two spaced pads are located on the same horizontal plane.

[0007] Furthermore, the pad is located on the bottom surface of the ceramic housing base or the upper surface of the side step structure.

[0008] Furthermore, the bent lead needle is composed of horizontal segments at both ends and a middle oblique line segment connecting the horizontal segments at both ends.

[0009] Beneficial effect: The small-pitch lead connection structure of the ceramic shell of the utility model sets the pads on the base of the ceramic shell on horizontal planes of different heights, and uses the elevation space to increase the spacing between the leads. This design ensures the insulation resistance between the leads while realizing the extremely small pitch requirement of the ceramic shell, thereby meeting the miniaturization of multi-pin ceramic packaging structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the small pitch lead connection structure of the ceramic housing;

[0011] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure along the pad arrangement;

[0012] Figure 3 This is a schematic diagram of the structure of each lead pin in the lead frame before being bent;

[0013] Figure 4 It is a schematic diagram of the structure of bending the lead wire;

[0014] Figure 5 The figure is a schematic diagram of the cross-sectional structure of the existing small pitch lead connection structure of the ceramic housing. DETAILED DESCRIPTION

[0015] The utility model is further explained below in conjunction with the accompanying drawings.

[0016] In view of the requirement for an extremely fine pitch ceramic housing, a ceramic housing fine pitch lead connection structure of this embodiment includes a ceramic housing base 1, a ceramic housing base 1 and a lead frame 2. Figure 1 As shown, according to the structure of the packaged chip, one or more rows of pads 1-1 for one-to-one connection with each lead pin 2-1 on the lead frame 2 are provided on the bottom surface or the upper surface of the side step structure of the ceramic housing base 1, and adjacent pads 1-1 are located on different horizontal planes, and the elevation difference between adjacent pads 1-1 is greater than 0.2mm, and the pitch is greater than or equal to 0.45mm.

[0017] In this embodiment, in a row of pads 1-1 located on the same side, two pads 1-1 spaced apart are located on the same horizontal plane, that is, the pads are distributed as follows: Figure 2 The peak and trough positions of the square wave structure are shown in FIG. Correspondingly, in order to connect the pads 1-1 on different horizontal planes, as shown in FIG. Figure 3 At least one of two adjacent lead pins 2 - 1 on the lead frame 2 is a bent lead pin.

[0018] Figure 4 As shown, the bent lead needle is composed of horizontal sections at both ends and a middle oblique line section connecting the horizontal sections at both ends, and the horizontal section at one end is welded to the corresponding pad 1-1.

[0019] The material of the ceramic housing base 1 is high-temperature alumina ceramic or low-temperature alumina; the material of the lead pin is iron-nickel alloy or CP; the solder used for welding is Ag72Cu28 or silver-based solder.

[0020] In this implementation case: Figure 2 As shown, when the width a of the lead pin 1-1 is 0.15mm and the width b of the pad 1-2 is 0.30mm, the distance difference c' between adjacent pads in elevation can be increased to 0.40mm, which is much larger than the 0.2mm required by the standard, ensuring the insulation resistance between adjacent lead pins. Finally, it is determined that the minimum pitch d can be reduced to 0.45mm. Taking a miniaturized product as an example, 17 pins can be welded on its shell by adopting this design.

[0021] According to the conventional existing design, such as Figure 5 As shown, when the width a of the lead pin 1-1 is 0.15mm and the width b of the pad 1-2 is 0.30mm, in order to ensure that the insulation resistance between adjacent lead pins is qualified, the minimum spacing c between adjacent pads is 0.20mm, and the final minimum pitch d is determined to be 0.65mm. Only 10 pins can be soldered on the same size of the housing, which is far less than the 17 pins in this design.

[0022] In some embodiments, the two spaced pads 1 - 1 may be arranged on different horizontal planes, that is, a multi-step structure is formed, so as to further improve the insulation resistance between adjacent lead pins.

[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 ceramic housing small pitch lead connection structure, characterized in that: The invention comprises a ceramic housing base (1), the ceramic housing base (1) and a lead frame (2); the ceramic housing base (1) is provided with at least one row of pads (1-1) for one-to-one connection with lead pins (2-1) on the lead frame (2); adjacent pads (1-1) are located on different horizontal planes, the elevation difference is greater than 0.2 mm, and the pitch is greater than or equal to 0.45 mm; at least one of two adjacent lead pins (2-1) on the lead frame (2) is a bent lead pin and is welded to the corresponding pad (1-1).

2. The ceramic housing fine pitch lead connection structure according to claim 1, characterized in that: The two spaced pads (1-1) are located on the same horizontal plane.

3. The ceramic housing fine pitch lead connection structure according to claim 1 or 2, characterized in that: The solder pad (1-1) is located on the bottom surface of the ceramic housing base (1) or the upper surface of the side step structure.

4. The ceramic housing fine pitch lead connection structure according to claim 3, characterized in that: The bent lead needle is composed of horizontal sections at two ends and a middle oblique line section connecting the horizontal sections at the two ends.

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