Packaging method of image sensor

Abstract

The invention relates to a packaging method of an image sensor, which comprises the steps of providing an image sensor chip and a support frame; bonding the first end of each metal wire to a pad of the image sensor chip, and suspending the second end of the metal wire on the image sensor chip; and bonding the image sensor chip and the support frame together, wherein the support frame completely orpartially cover the pads, thereby increasing the distance between a light sensing area of the image sensor and the inner side of the support frame, and reducing the influence of stray light.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to an image sensor packaging method. Background technique [0002] Currently, mainstream image sensor (CIS: CMOS Image Sensor) packaging methods include: Chip Scale Package (CSP), Chip On Board (COB) and Flip Chip Package (FlipChip, FC) . [0003] CIS CSP is a Wafer level (wafer level) packaging technology commonly used in low-end, low-pixel (2M pixels or below) image sensors. This packaging technology uses wafer-level glass to bond with the wafer and uses dams to separate the image sensor chips on the wafer, and then makes pad surface or pad in-plane holes in the pad area of ​​the wafer after grinding Through-silicon via technology (TSV: Through Silicon Via) with side ring metal connection or T-shaped metal contact chip size packaging technology on the side of the pad after cutting, and make solder ball grid array (BGA: Ball GridArray) after extending the circuit on the...

AI Technical Summary

Problems solved by technology

However, CSP packaging has the following obvious problems: 1. It affects product performance: the absorption, refraction, reflection and scattering of light by thick support glass have a great impact on the performance of image sensors, especially products with small pixel sizes; 2. Reliability issues : The thermal expansion coefficient difference between the components in the packaging structure and the sealing gas in the cavity have reliability problems in the subsequent SMT process or changes in the product use environment; 3 large investment scale, large environmental pollution control requirements, and long production cycle , the unit chip cost is high, especially for high-pixel and large-size image sensor products

However, COB packaging has the following obvious problems: 1. Dust control is very difficult, requiring ultra-high clean room levels, and manufacturing maintenance costs are high; 2. Product design is customized, the cycle is long, and the flexibility is not enough; 3. It is not easy to scale production ;

However, the FC package has the following obvious problems: 1. The package has high requirements on the PCB substrate, and has a similar thermal expansion coefficient to Si, and the cost is very high; 2. Manufacturing reliability is very difficult, and the connection between all the bumps and pads of the thermosonic is consistent. Very high performance requirements, bumps and pads are hard-connected, and the ductility is not good; 3. The dust control is difficult, the process environment requirements are high, and the cost is high;

[0006] figure 1 It is a packaging method in the prior art. The first end of the metal wire 120 is bonded to the pad 130 of the image sensor chip 100, and the other end of the metal wire is suspended from the image sensor chip 100. In the photosensitive area 110 of the image sensor chip 100 The upper part is equipped with a support frame 200, and a light-transmitting cover plate 300 on the support frame 200. In the prior art, the support area of ​​the support frame 200 is located next to the photosensitive area 110. When the light irradiates the image sensor chip 100, Since the supporting area of ​​the supporting frame 200 is relatively close to the photosensitive area 110, stray light will be brought, which will affect the imaging quality of the image.

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