CN105244384A - Vacuum packaging structure of infrared imaging chip - Google Patents

Abstract

The invention discloses a vacuum packaging structure for an infrared imaging chip, comprising an infrared window, an infrared imaging chip, two spacers, a getter, and a visible light window; wherein, the spacer is bonded on the upper surface of the visible light window to form a The packaged cavity, the infrared imaging chip and the getter are arranged in the cavity, the getter is located between the infrared imaging chip and the upper surface of the visible light window, and the infrared window is bonded to the cavity to form a vacuum-sealed cavity. The present invention can selectively anti-transmit infrared radiation with a wavelength of 8-14 μm, effectively protect the fragile internal chip structure, and has good sealing performance; the air leakage rate of the vacuum packaging structure is low; the packaging structure of the present invention is simple, low power consumption and low cost .

Description

A vacuum packaging structure for an infrared imaging chip

technical field

The invention relates to the technical field of semiconductor optoelectronics, in particular to a vacuum packaging structure for an infrared imaging chip.

Background technique

Infrared imaging technology is more and more widely used in industrial sensing, image monitoring, automobile industry, fire search and rescue, and even military navigation and night vision. Infrared focal plane detector manufacturing technology is the core of thermal imaging technology, and infrared focal plane array detector chip sealing packaging technology is the key link to realize infrared detector imaging. Infrared focal plane array detector chip needs to be in a sealed environment under vacuum Otherwise, the imaging function of its bolometer cannot be exerted. Generally speaking, the high-vacuum packaging technology of infrared focal plane array detector uses a metal shell as a sealed cavity.

Vacuum packaging is essential for infrared focal plane array (IRFPA) chips. IRFPA needs encapsulation to protect the internal fragile microstructure from damage caused by external water vapor, dust, etc.; more importantly, it needs a vacuum environment to ensure the normal operation of the chip. So far, there have been many vacuum packaging schemes for electrical readout IRFPA, which can be divided into chip-level packaging, wafer-level packaging and pixel-level packaging. Chip-level vacuum packaging is the earliest vacuum packaging method developed and is still widely used, but its packaging efficiency is relatively low. Wafer-level vacuum packaging improves packaging efficiency, but this method requires a high yield of IRFPA chips, otherwise, a considerable proportion of waste chips will be packaged, thereby wasting expensive infrared filters. Developed by CEA-LETI, its innovation is to vacuum-encapsulate the pixels with a semiconductor film on the wafer; however, the film is used as the package cover in the scheme, which is relatively fragile and difficult to effectively protect the fragile internal pixel structure; and there is no light The visible window required to read out the infrared focal plane array chip.

The existing packaging structure has many internal components and is large in volume. With the development of infrared thermal imaging technology, the market requires that the volume of infrared thermal imaging equipment be as small as possible. Especially for some portable infrared thermal imaging equipment, the existing packaging structure cannot meet the requirements of compactness. The requirements of the structure, and this package has many structural components, high power consumption, high cost and difficult manufacturing process. Moreover, for some infrared focal plane detector chips, in some cases, they need to work in an environment with good thermal insulation from the outside world, and the above-mentioned existing packaging structure cannot meet the application requirements.

How to solve the deficiencies of the existing technology has become one of the important problems that need to be solved urgently in the field of semiconductor optoelectronic technology.

Contents of the invention

The technical problem to be solved by the present invention is to provide a vacuum packaging structure for infrared imaging chips by overcoming the deficiencies in the prior art. it is good.

The present invention adopts the following technical solutions for solving the problems of the technologies described above:

A vacuum packaging structure for an infrared imaging chip proposed according to the present invention includes an infrared window, an infrared imaging chip, two gaskets, a getter, and a visible light window; wherein, the gasket is bonded on the upper surface of the visible light window to form a A vacuum-encapsulated cavity, the infrared imaging chip and the getter are arranged in the cavity, the getter is located between the infrared imaging chip and the upper surface of the visible light window, and the infrared window is bonded to the cavity to form a vacuum-sealed cavity .

As a further optimization scheme of the infrared imaging chip vacuum packaging structure described in the present invention, the gasket is a silicon gasket.

As a further optimization scheme of the infrared imaging chip vacuum packaging structure described in the present invention, the material of the visible light window is glass.

As a further optimization scheme of the infrared imaging chip vacuum packaging structure described in the present invention, the infrared imaging chip is bonded to the upper surface of the visible light window by solder.

As a further optimization scheme of the infrared imaging chip vacuum packaging structure described in the present invention, the getter is an electrically activated getter.

As a further optimization scheme of the infrared imaging chip vacuum packaging structure described in the present invention, the material of the infrared window is a silicon wafer.

Compared with the prior art, the present invention adopts the above technical scheme and has the following technical effects:

(1) The present invention can selectively enhance infrared radiation with a wavelength of 8-14 μm, effectively protect the fragile internal chip structure, and have good sealing performance;

(2) The air leakage rate of the vacuum packaging structure is low;

(3) The present invention has a simple packaging structure, low power consumption and low cost.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the present invention.

The reference signs in the figure are explained as: 1-infrared window, 2-infrared imaging chip, 3-gasket, 4-getter, 5-visible light window.

detailed description

Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:

As shown in Figure 1, a vacuum packaging structure for an infrared imaging chip includes an infrared window 1, an infrared imaging chip 2, two gaskets 3, a getter 4, and a visible light window 5; wherein, the gasket is bonded to the visible light window The upper surface forms a cavity for vacuum packaging, the infrared imaging chip and the getter are arranged in the cavity, the getter is located between the infrared imaging chip and the upper surface of the visible light window, and the infrared window is bonded to the cavity , forming a vacuum-tight cavity.

The gasket is a silicon gasket.

The visible light window is made of glass.

The infrared imaging chip is bonded on the upper surface of the visible light window through solder.

The getter is an electro-active getter.

The infrared window is made of silicon wafer.

The silicon gasket and the visible light window are anodically bonded to form a package cavity for placing the chip; the infrared window not only performs selective anti-reflection for infrared radiation with a wavelength of 8-14 μm, but also serves as a package cover, which can better protect Internal fragile chip structure.

The manufacturing process of the vacuum packaging structure is as follows:

1) Using a wet etching process to make a silicon gasket;

2) The silicon gasket and the visible light window are anodically bonded to form a packaging cavity;

3) Au is fabricated and patterned on the package cavity to form an Au adhesion layer;

4) bonding the chip solder into the package cavity;

5) Use a common silicon wafer as an infrared window, sputter Au on it and pattern it to form an adhesion layer;

6) The infrared window is solder-bonded to the package cavity chip in a vacuum environment to complete the vacuum package.

The silicon gasket and the visible light window (glass) are anodically bonded to form a packaging cavity for placing chips; the infrared window not only selectively prevents infrared radiation in the 8-14 μm band, but also acts as a packaging cover; the packaging cavity and infrared window Vacuum packaging is accomplished by solder bonding within the vacuum chamber. The packaging structure has passed the airtight test, and the thermal image of a 200°C soldering iron has been obtained from the test. The vacuum-encapsulated infrared imaging chip can clearly image an electric soldering iron at 180° C., which shows that the vacuum-encapsulation method is effective.

The above embodiments are only to illustrate the technical ideas of the present invention, and cannot limit the scope of protection of the present invention for this reason. Any changes made on the basis of technical solutions according to the technical ideas proposed in the present invention all fall within the scope of protection of the present invention. Inside.

Claims (6)

1. A vacuum packaging structure for an infrared imaging chip, characterized in that it comprises an infrared window, an infrared imaging chip, two spacers, a getter, and a visible light window; wherein the spacer is bonded on the upper surface of the visible light window to form a In a vacuum-encapsulated cavity, the infrared imaging chip and the getter are arranged in the cavity, the getter is located between the infrared imaging chip and the upper surface of the visible light window, and the infrared window is bonded to the cavity to form a vacuum-sealed cavity body. 2 . The infrared imaging chip vacuum packaging structure according to claim 1 , wherein the spacer is a silicon spacer. 3 . 3 . The infrared imaging chip vacuum packaging structure according to claim 1 , wherein the visible light window is made of glass. 4 . 4 . The infrared imaging chip vacuum packaging structure according to claim 1 , wherein the infrared imaging chip is bonded to the upper surface of the visible light window by solder. 5 . The infrared imaging chip vacuum packaging structure according to claim 1 , wherein the getter is an electrically activated getter. 6 . The infrared imaging chip vacuum packaging structure according to claim 1 , wherein the material of the infrared window is a silicon wafer. 7 .