CN1426115A

CN1426115A - Gallium nitride base detector without visible light interference read out circuit and preparing method

Info

Publication number: CN1426115A
Application number: CN 02145468
Authority: CN
Inventors: 王平; 朱龙源; 刘诗嘉; 李向阳; 龚海梅
Original assignee: Shanghai Institute of Technical Physics of CAS
Current assignee: Shanghai Institute of Technical Physics of CAS
Priority date: 2002-11-18
Filing date: 2002-11-18
Publication date: 2003-06-25
Anticipated expiration: 2022-11-18
Also published as: CN1288760C

Abstract

The gallium nitride base detector without visible light interference to its read-out circuit incldues array chip and read-out circuit and features that between the arry chip and read-out circuit there is one black polyimide sandwich capable of absorbing visible light. The preparation process of the detector, especially the black polyimide sandwich, is also disclosed. Owing to the black polyimide sandwich, when the incident signal to the detector is from the back, the sandwich can absorb visible light and this can raise the work performance of the read-out circuit. In addition, the sandwith can also deactivate the read-out circuit, gallium nitride base chip and indium column to raise the reliability of ultraviolet focal plane device.

Description

The gallium nitrate based detector and the preparation method of no visible light interference read out circuit

Technical field

The present invention relates to photodetector, specifically be meant a kind of gallium nitrate based detector and preparation method who does not have visible light interference read out circuit.

Background technology

The basic focal plane array detector of gallium nitride (GaN) mainly is made up of array chip and reading circuit.For the focal plane array detector, generally adopt the method for indium post inverse bonding interconnection, reading circuit is interconnected to array chip, form the focal plane array detector, promptly so-called back of the body incident structure.Yet because the broad stopband characteristics of gallium nitride-based material, they do not absorb substantially to visible light, make the part visible light can see through gallium nitride and shine on the reading circuit, make reading circuit in the interference that is subjected to visible light in varying degrees.Therefore, when working in incoming signal, this class focal plane device comprises under the situation of ultraviolet and visible light composition, it is unnecessary or even influence the phenomenon of device work some to occur, such as: glitch phenomenon, the temperature rise that works long hours, that temperature is floated is aging etc. with reading circuit, and these phenomenons influence the overall performance of detector.The relevant report that solves this respect technology does not also have disclosed document, may be in view of military application prospect but up to the present.

Summary of the invention

The objective of the invention is to propose a kind of gallium nitrate based focus planardetector that does not have the reading circuit of visible light interference, its reading circuit is worked under the state of no visible light, to improve stability, reliability and the working life of device.The preparation method of this kind structure devices has also been proposed simultaneously.

For achieving the above object, technical scheme of the present invention is as follows:

Gallium nitrate based detector comprises: array chip 1 and reading circuit 2 have the black polyimide layer 3 of a visible light absorbing between array chip and reading circuit.When incoming signal during from the back surface incident of detector, because the existence of interlayer, interlayer absorbs visible light, and visible light does not arrive reading circuit, improves the service behaviour of reading circuit with this.

The gallium nitrate based detector preparation method of said structure comprises the steps:

1. the preparation of array chip:

Array chip 1 adopts existing common process, the nitride multilayer gallium sill that will have white stone substrate 101 is by semiconductor technologies such as photoetching, reactive ion etching, metal electrode preparations, form the photosensitive unit 102 of back-illuminated type array, and in each photosensitive unit, make indium post figure by lithography, stand-by.

2. the preparation of reading circuit:

Reading circuit 2 is fabricated from a silicon, and adopts common process to form reading circuit by technologies such as photoetching, ion injection, etchings on silicon chip, and makes the indium post 201 that is used to interconnect.

3. the preparation of interlayer:

The black polyimide layer 3 of preparation on array chip or reading circuit.

4. make interconnection indium post 103 at last in array chip indium post district, corresponding one by one with the indium post 201 on the reading circuit, photosensitive first indium post and the corresponding one by one heating inverse bonding of reading circuit indium post interconnection are formed a kind of gallium nitrate based detector that does not have visible light interference read out circuit.

The preparation method of said black polyimide layer 3 is as follows:

A. with aromatic diamines and dicarboxylic anhydride with 0.9: 1-1.5: 1 mass ratio, under the pure nitrogen gas environment, under 70-78 ℃ of temperature, the open loop addition generated polyamic acid in 16-18 hour.

B. with the polyamic acid that generates and epoxy melanin with 9: 1-12: 1 mass ratio mixes, and stirs, and generates black polyamic acid, and lucifuge low temperature is preserved stand-by.

C. in the time will using, at room temperature, the black polyamic acid that had before prepared is dissolved in the phenodiazine dimethylacetylamide, concentration is 10-15%.

D. the array chip with the good indium post of photoetching figure is placed on the sol evenning machine, splash into the black polyamic acid and the phenodiazine dimethylacetylamide mixed solution that had before prepared, with the even glue of 2500-3000 rev/min speed, then with in 50 ℃ of baking ovens of its horizontal positioned, dried by the fire 20-24 hour, and, generated the black polyimides of 4-7 micron thickness the organic solvent oven dry, do not reach requirement as thickness, can repeat above-mentioned even glue process.

E. rapidly the black polyimides of indium post position is removed with the floating glue method of ethanol again, be placed in 50 ℃ of baking ovens, dried by the fire 2 hours, residual ethanol is removed.

F. in the pure nitrogen gas environment, array chip is warming up to 250-350 ℃, makes black polyimide layer cyclodehydration.Then it is positioned in the vacuum chamber, vacuumized 24 hours, get rid of gas in the body as far as possible.

The black polyimide layer shading rate of the 4-7 micron thickness of making thus can be up to more than 93%, and desirable stability, venting rate and insulating properties are arranged.

The great advantage of above-mentioned device architecture is:

1. because intermediate course adopts black polyimide layer, eliminated the influence of visible light, improved the stability of focal plane device the silicon reading circuit.

2. intermediate course has not only shielded the influence of visible light to the silicon reading circuit, can also play the passivation to reading circuit, gallium nitrate based chip and indium post, has improved the reliability of ultraviolet focal-plane device.

Description of drawings

Fig. 1 is an array focal plane device floor map of the present invention;

Fig. 2 is the A-A generalized section of Fig. 1;

Fig. 3 is the graph of relation of black polyimide layer wavelength and transmitance.

Embodiment

The key of success of the present invention is the choosing of sandwich material, proportioning and preparation technology.Device to the requirement of interlayer is:

Must have minimum gas saturation not expand when working in vacuum environment so that the indium post is broken to guarantee device, venting rate that simultaneously must be very little is to guarantee vacuum degree;

The indium post heats in the interconnected process temperature will be up to 250-300 ℃, thus interlayer is essential under this temperature can not carbonization, undecomposable, can not softening transform;

Interlayer also will have good insulation performance, because the indium post is the signal conductor that exposes, interlayer directly contacts with them, thus must prevent the signal cross-talk, and the interlayer evenness will be got well.

The following inventor provides the black polyimide layer proportioning and the preparation technology that optimize:

A. aromatic diamines and dicarboxylic anhydride were with 1: 1 mass ratio, and under the pure nitrogen gas environment, under 75 ℃ of temperature, the open loop addition generated polyamic acid in 16 hours.

B. the polyamic acid that generates and the epoxy melanin mass ratio with 9: 1 is mixed, and stir, generate black polyamic acid, lucifuge low temperature is preserved stand-by.

C. in the time will using, at room temperature, the black polyamic acid that had before prepared is dissolved in the phenodiazine dimethylacetylamide, concentration is 12%.

D. the array chip with the good indium post of photoetching figure is placed on the sol evenning machine, splash into black polyamic acid and phenodiazine dimethylacetylamide mixed solution that 2ml had before prepared, with the even glue of 3000 rev/mins speed, then with in 50 ℃ of baking ovens of its horizontal positioned, dried by the fire 20-24 hour, with the organic solvent oven dry, generate the polyimides interlayer of 5 micron thickness.

E. rapidly the polyimides of indium post position is removed with the floating glue method of ethanol again, be placed in 50 ℃ of baking ovens, dried by the fire 2 hours, residual ethanol is removed.

F. in the pure nitrogen gas environment, array chip is warming up to 350 ℃, makes black polyimide layer cyclodehydration.Then it is positioned in the vacuum chamber, vacuumized 24 hours, get rid of gas in the body as far as possible.

The black polyimides layer thickness of above-mentioned prepared is 5mm, and its shading rate to visible light is seen Fig. 3.

Claims

1. gallium nitrate based detector that does not have visible light interference read out circuit, comprising: array chip (1) and reading circuit (2) is characterized in that: the black polyimide layer (3) that a visible light absorbing is arranged between array chip and reading circuit.

2. a preparation method who does not have the gallium nitrate based detector of visible light interference read out circuit comprises the steps:

A. the preparation of array chip (1):

Array chip adopts existing common process, the nitride multilayer gallium sill that will have white stone substrate (101) is by semiconductor technologies such as photoetching, reactive ion etching, metal electrode preparations, form the photosensitive unit of back-illuminated type array (102), and in each photosensitive unit, make indium post figure by lithography, stand-by;

B. the preparation of reading circuit (2):

Reading circuit is fabricated from a silicon, adopt common process on silicon chip by prepared reading circuits such as photoetching, ion injection, etchings, and the indium post (201) that making is used to interconnect on reading circuit;

C. the preparation of interlayer:

The black polyimide layer (3) of preparation on array chip or reading circuit;

D. make interconnection indium post (103) at last in array chip indium post district, corresponding one by one with the indium post (201) on the reading circuit, photosensitive first indium post and the corresponding one by one heating inverse bonding of reading circuit indium post interconnection are formed a kind of gallium nitrate based detector that does not have visible light interference read out circuit;

It is characterized in that: step C. deceives the preparation method of polyimide layer (3):

C1. with aromatic diamines and dicarboxylic anhydride with 0.9: 1-1.5: 1 mass ratio, under the pure nitrogen gas environment, under 70-78 ℃ of temperature, the open loop addition generated polyamic acid in 16-18 hour;

C2. with the polyamic acid that generates and epoxy melanin with 9: 1-12: 1 mass ratio mixes, and stirs, and generates black polyamic acid, and lucifuge low temperature is preserved stand-by;

C3. in the time will using, at room temperature, the black polyamic acid that had before prepared is dissolved in the phenodiazine dimethylacetylamide, concentration is 10-15%;

C4. the array chip with the good indium post of photoetching figure is placed on the sol evenning machine, splash into the black polyamic acid and the phenodiazine dimethylacetylamide mixed solution that had before prepared, with the even glue of 2500-3000 rev/min speed, then with in 50 ℃ of baking ovens of its horizontal positioned, dried by the fire 20-24 hour, and, generated the black polyimide layer of 4-7 micron thickness the organic solvent oven dry, do not reach requirement as thickness, can repeat above-mentioned even glue process;

C5. rapidly the black polyimides of indium post position is removed with the floating glue method of ethanol again, be placed in 50 ℃ of baking ovens, dried by the fire 2 hours, residual ethanol is removed;

C6. in the pure nitrogen gas environment, array chip is warming up to 250-350 ℃, makes black polyimide layer cyclodehydration, then it is positioned in the vacuum chamber, vacuumized 24 hours, get rid of gas in the body as far as possible.