阅读说明：本技术 一种红外探测器封装结构及封装方法 (Infrared detector packaging structure and packaging method ) 是由 刘志双 曾广锋 高涛 陈玉成 于 2021-07-20 设计创作，主要内容包括：本发明公开了一种红外探测器封装结构,包括封装壳体、红外芯片、光学窗口和金属焊盘,封装壳体与光学窗口组成真空密闭腔体,封装壳体内底部上设有金属凹槽,且金属凹槽的至少两个角具有与凹槽连通的凹陷,红外芯片通过导电浆贴装于金属凹槽底面上,且金属凹槽槽壁与红外芯片侧壁的最大距离不大于红外芯片的最大允许偏移量。还提供了一种该红外探测器的封装方法。该红外探测器封装结构的结构简单、容易实现、且能同时克服对于芯片的偏移控制的问题及后续封装过程中存在的导电银浆容易溢出导致短路等问题；本发明的封装方法工艺简单,可控性强,用肉眼和普通放大镜即能判定偏移量好坏,能够提高生产效率,有效降低成本。(The invention discloses an infrared detector packaging structure which comprises a packaging shell, an infrared chip, an optical window and a metal bonding pad, wherein the packaging shell and the optical window form a vacuum sealed cavity, a metal groove is formed in the inner bottom of the packaging shell, at least two corners of the metal groove are provided with a recess communicated with the groove, the infrared chip is attached to the bottom surface of the metal groove through conductive paste, and the maximum distance between the groove wall of the metal groove and the side wall of the infrared chip is not greater than the maximum allowable offset of the infrared chip. A packaging method of the infrared detector is also provided. The infrared detector packaging structure is simple in structure and easy to implement, and can simultaneously solve the problems of offset control of a chip and short circuit caused by easy overflow of conductive silver paste in the subsequent packaging process; the packaging method provided by the invention has the advantages of simple process and strong controllability, and can judge whether the offset is good or bad by naked eyes and a common magnifier, so that the production efficiency can be improved, and the cost is effectively reduced.)

1. The utility model provides an infrared detector packaging structure, its characterized in that includes packaging shell, infrared chip, optical window and metal pad, packaging shell and optical window constitute the airtight cavity in vacuum, its characterized in that, be equipped with the metal recess on the bottom in the packaging shell, just two at least corners of metal recess are equipped with the sunken of being linked together with the recess, infrared chip through electrically conductive thick liquid paste adorn in on the metal recess bottom surface, just the maximum distance of metal recess cell wall and infrared chip lateral wall is not more than the maximum allowable offset of infrared chip.

2. The infrared detector package structure as claimed in claim 1, wherein each of four corners of the metal recess is provided with a recess communicating with the metal recess; the recess is an arc-shaped groove; the height of the metal groove is 0.2-0.8 of the thickness of the infrared chip.

3. The infrared detector package structure according to claim 1 or 2, wherein the metal pads are disposed on two sides inside the package housing; the infrared chip is bonded with the metal bonding pad through a bonding wire; the back of the packaging shell is provided with a pin, and the infrared chip is electrically connected with the outside through a metal bonding pad and the pin.

4. The infrared detector package structure according to claim 1 or 2, wherein the optical window is a filter; the optical filter and the top of the packaging shell form a vacuum sealed cavity through welding.

5. A packaging method of an infrared detector is characterized in that a metal groove is formed on the inner bottom surface of a packaging shell, at least two corners of the metal groove are provided with a recess communicated with the metal groove, then an infrared chip is attached in the metal groove through conductive paste, and the maximum distance between the groove wall of the metal groove and the side wall of the infrared chip is not larger than the maximum allowable offset of the infrared chip.

6. The method for packaging an infrared detector as set forth in claim 5, comprising the steps of:

s1, providing a packaging shell, forming a metal pad in the packaging shell, and forming a metal groove on the inner bottom surface of the packaging shell, wherein at least two corners of the metal groove are provided with a recess communicated with the metal groove;

s2, providing an infrared chip, and attaching the infrared chip in the metal groove by adopting conductive paste;

s3, bonding the infrared chip and the metal bonding pad;

and S4, providing an optical window, and sealing the opening of the packaging shell by adopting the optical window to form a vacuum sealed cavity.

7. The method for packaging an infrared detector as claimed in claim 6, wherein the step S1 specifically includes:

(1) presetting an infrared chip mounting area range, wherein the mounting area range corresponds to the metal groove and the concave position, setting the setting position and the pattern of the patterned metal pad, and then forming a protective adhesive layer in the infrared chip mounting area range and the surrounding area at least surrounding the patterned metal pad in the packaging shell;

(2) placing the packaging shell into an electroplating bath for electroplating to form a patterned metal pad at the setting position of the patterned metal pad, forming a metal coating platform around the infrared chip mounting area, taking out the packaging shell after the coating thickness reaches a set range, and removing the protective adhesive layer in the range of the preset infrared chip mounting area to obtain a groove with a recess;

(3) and (4) arranging a protective adhesive layer in other areas except the concave groove, then putting the protective adhesive layer into an electroplating bath for electroplating, stopping electroplating after the plating layers on the bottom surface and the side wall of the groove meet the requirements, and removing the protective adhesive layer to obtain the metal groove for mounting the infrared chip.

8. The method for packaging an infrared detector as claimed in claim 6 or 7, wherein the step S2 specifically includes: the method comprises the steps of firstly coating conductive paste at a set position of a metal groove, attaching the infrared chip into the metal groove by using the adhesive force of the conductive paste, and then baking to attach the infrared chip into the metal groove.

9. The method for packaging an infrared detector as claimed in claim 6 or 7, wherein in step S4, the optical window is a filter; and the sealing is to perform vacuum welding on the optical window and the top of the packaging shell.

10. The method for packaging an infrared detector as claimed in claim 5 or 6, wherein four corners of the metal groove are each provided with a recess communicated with the metal groove; the recess is an arc-shaped groove; the height of the metal groove is 0.2-0.8 of the thickness of the infrared chip.

Technical Field

The invention belongs to the field of Chip On Board (COB) packaging of semiconductors and particularly relates to an infrared detector packaging structure and an infrared detector packaging method.

Background

The outer detector packaging is to slice the whole wafer into separate wafers, then fix the wafer and the wafer substrate in advance through conductive silver paste, and then qualitatively fix through high-temperature baking. The wafer deviation exceeds the standard due to the problems of equipment stability, material deviation, non-uniform expansibility of the baked conductive silver paste and the like; and the wafer da (die attach) needs to use the optical measurement instrument to measure the offset, which is not only inefficient, but also expensive.

The metal plating layer on the surface of the substrate has a flat surface, conductive silver paste is dotted, the wafer is pasted on the conductive silver paste, the quantity of the conductive silver paste, the route and time of the silver paste and the pressure parameter instability of DA (die attach) equipment are dotted in the manufacturing process, so that the conductive silver paste easily overflows the wafer boundary in the wafer pasting process, and the risk of short circuit is generated.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides the packaging structure for the infrared detector, which is simple in structure and easy to realize, and can simultaneously overcome the problems of offset control on a chip, short circuit caused by easy overflow of conductive silver paste in the subsequent packaging process and the like; meanwhile, the packaging method for the infrared detector is capable of effectively reducing cost, improving production efficiency, simple in process and strong in controllability, and the offset can be judged by naked eyes and a common magnifier.

In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problems is as follows:

the utility model provides an infrared detector packaging structure, includes packaging shell, infrared chip, optical window and metal pad, packaging shell and optical window constitute the airtight cavity in vacuum, be equipped with the metal recess on the internal bottom of packaging shell, just two at least corners of metal recess are equipped with the sunken of communicating with the recess, infrared chip through electrically conductive thick liquid paste adorn in on the metal recess bottom surface, just the maximum distance of metal recess cell wall and infrared chip lateral wall is not more than the maximum allowable offset of infrared chip.

Preferably, four corners of the metal groove are provided with depressions communicated with the metal groove; the recess is an arc-shaped groove; the height of the metal groove is 0.2-0.8 of the thickness of the infrared chip, and further preferably 0.35-0.7.

Preferably, the metal pads are arranged on two sides in the packaging shell; the infrared chip is bonded with the metal bonding pad through a bonding wire (such as a gold wire); and a pin is arranged on the back (namely the bottom) of the packaging shell, and the infrared chip is electrically connected with the outside through a metal bonding pad and the pin in the packaging shell.

Preferably, the optical window is an optical filter; the optical filter and the opening of the packaging shell form a vacuum closed cavity through welding.

As a general inventive concept, there is also provided a method for packaging an infrared detector, in which a metal groove is formed on an inner bottom surface of a package casing, at least two corners of the metal groove have recesses communicated with the metal groove, and then an infrared chip is mounted in the metal groove by a conductive paste, and a maximum distance between a groove wall of the metal groove and a side wall of the infrared chip is not greater than a maximum allowable offset of the infrared chip.

The packaging method of the infrared detector comprises the following steps:

s1, providing a packaging shell, forming a metal pad in the packaging shell, and forming a metal groove on the inner bottom surface of the packaging shell, wherein at least two corners of the metal groove are provided with a recess communicated with the metal groove;

s2, providing an infrared chip, and then mounting the chip in the metal groove by adopting conductive paste;

s3, bonding the infrared chip and the metal bonding pad;

and S4, providing an optical window, and sealing the opening of the packaging shell by adopting the optical window to form a vacuum sealed cavity.

Preferably, step S1 specifically includes:

(1) presetting an infrared chip mounting area range, wherein the mounting area range corresponds to the metal groove and the concave position, setting the setting position and the pattern of the patterned metal pad, and then forming a protective adhesive layer in the infrared chip mounting area range and the surrounding area at least surrounding the patterned metal pad in the packaging shell;

(2) placing the packaging shell into an electroplating bath for electroplating to form a patterned metal pad at the setting position of the patterned metal pad, forming a metal coating platform around the infrared chip mounting area, taking out the packaging shell after the coating thickness reaches a set range, and removing the protective adhesive layer in the range of the preset infrared chip mounting area to obtain a groove with a recess;

(3) and (4) arranging a protective adhesive layer in other areas except the concave groove, then putting the protective adhesive layer into an electroplating bath for electroplating, stopping electroplating after the plating layers on the bottom surface and the side wall of the groove meet the requirements, and removing the protective adhesive layer to obtain the metal groove for mounting the infrared chip.

Preferably, step S2 specifically includes: the method comprises the steps of firstly coating conductive paste at a set position of a metal groove, attaching the infrared chip into the metal groove by using the adhesive force of the conductive paste, and then baking to attach the infrared chip into the metal groove.

Preferably, in step S4, the optical window is an optical filter; and the sealing is to perform vacuum welding on the optical window and the top of the packaging shell.

Preferably, four corners of the metal groove are provided with a recess communicated with the metal groove; the recess is an arc-shaped groove.

The beneficial effects produced by the invention are as follows:

1. the sunken metal groove is arranged on the substrate and used for chip mounting, the size of the metal groove is controlled to enable the maximum distance between the groove wall of the metal groove and the side wall of the chip not to exceed the maximum allowable offset of the chip, the offset range of the chip can be effectively controlled, the quality of the offset can be judged by naked eyes and a common magnifier, the production efficiency is improved, and the detection cost is reduced. Meanwhile, through at least two corners of the metal groove, for example, the four corners of the metal groove are provided with the depressions communicated with the metal groove, when the chip is pasted by using the conductive silver paste, the overflowed conductive paste can be blocked by the side wall of the metal groove with a certain height on one hand, and on the other hand, even if the conductive paste is more, the overflowed conductive paste can flow into the depressions, so that the risk of short circuit caused by the overflow of the conductive paste can be avoided; the packaging structure is simple and ingenious in conception, the offset control of the chip can be realized through the integral groove structure, the problems that conductive silver paste is easy to overflow in the subsequent packaging process to cause short circuit and the like can be solved, and the packaging cost and the process difficulty can be greatly reduced.

2. According to the invention, the sunken metal grooves are formed on the substrate through the metalized plating, and the depressions communicated with the metal grooves are formed on at least two corners of the metal grooves, so that the problems of wafer exceeding easily, low detection efficiency and high cost in chip mounting in the packaging process, short circuit caused by easy overflow of silver paste in the mounting process and other risks can be solved simultaneously.

3. In the invention, the metal groove is formed by a metal electroplating method, so that the adhesive force is strong, the cost is low, the required shape can be designed according to the requirement, and the process controllability is strong.

Drawings

Fig. 1 is a side view of an infrared detector package structure.

Fig. 2 is a schematic view of an infrared detector package structure without sealing.

Fig. 3 is an exploded view of an infrared detector package.

Reference numerals:

1. an infrared chip; 2. bonding lines; 3. a package housing; 4. a metal pad; 5. a pin; 6. an optical window; 7. and (6) a metal groove.

Detailed Description

The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention.

An infrared detector packaging structure is shown in figures 1-3 and comprises a packaging shell 3, an infrared chip 1, an optical window 6 and a metal pad 4, wherein a pin 5 is arranged at the bottom (back) of the packaging shell 3, the packaging shell 3 and the optical window 6 form a vacuum sealed cavity, a metal groove 7 is arranged in the center of the bottom in the packaging shell 3, an electroplating metal layer is arranged on the inner bottom surface of the packaging shell 3 around the metal groove 7, arc-shaped grooves communicated with the metal groove 7 are formed in four corners of the metal groove 7, the infrared chip 1 is attached to the bottom surface of the metal groove 7 through conductive paste, and the maximum distance between the groove wall of the metal groove 7 and the side wall of the infrared chip 1 is not larger than the maximum allowable offset of the infrared chip 1. In this embodiment, the metal groove 7 is a square metal groove. The maximum allowable offset here refers to the maximum movement range value allowed by the design of the infrared chip 1 in the metal groove 7 in the X-axis and Y-axis directions. The pins 5 at the bottom of the package housing 3 are connected to the metal pads 4 in the package housing 3, and the electrical connection can be realized by adopting a conventional manner in the art, generally, the pins 5 and the metal pads 4 are electrically connected through the metalized vias on the inner bottom surface of the package housing 3, and the required metalized vias can be obtained by purchasing the package housing 3 with the metalized vias, or by performing subsequent drilling and electroplating.

In this scheme, be used for infrared chip 1 to paste the dress through set up sunken metal recess 7 on the bottom surface in packaging shell 3, and the size of control metal recess 7 makes the maximum distance of metal recess 7 cell wall and infrared chip 1 lateral wall be no longer than infrared chip 1's the most allowable offset, and be equipped with the arc wall with metal recess 7 intercommunication at four angles of metal recess 7, can effectively control infrared chip 1's skew scope, adopt naked eye and ordinary magnifying glass even can judge the quality of offset, and the improvement production efficiency, it has certain degree of depth and recess angle department to have the arc recess simultaneously because of metal recess 7, can avoid silver thick liquid excessive risk that causes short circuit on every side.

In this scheme, metal recess 7 highly be 1/2 of infrared chip 1 thickness, and metal recess 7's height can be adjusted according to actual demand in fact.

The shape of the metal groove 7 is the same as that of the infrared chip 1 (wafer), but the area of the metal groove is equal to the product of the area of the wafer and the maximum value of the X-axis offset and the Y-axis offset, the DA offset of the wafer can be directly judged to be beyond a standard value by naked eyes by the wafer DA process technology as long as the wafer is placed in the metal groove 7, and the effect of improving the process level and preventing the fool in the manufacturing process can be obtained without independently using an optical measuring instrument for calculation.

The metal pads 4 are arranged on two opposite sides in the packaging shell 3, and no plated metal layer is arranged around the metal pads 4 and is a ceramic layer of the packaging shell 3; the infrared chip 1 is bonded with the metal bonding pad 4 through the bonding wire 2.

The optical window 6 is an optical filter; the optical filter and the opening of the packaging shell 3 are welded to form a vacuum sealed cavity.

According to the method, metal grooves 7 are formed in the inner bottom surface of a packaging shell 3, arc-shaped grooves communicated with the metal grooves 7 are formed in four corners of each metal groove 7, then the infrared chip 1 is attached in the metal grooves 7 through conductive silver paste, and the maximum distance between the groove wall of each metal groove 7 and the side wall of the infrared chip 1 is not larger than the maximum allowable offset of the infrared chip 1. In the chip mounting process, because metal groove 7 has a certain height, unnecessary conductive silver paste is held back in metal groove 7 on the one hand, and on the other hand, even conductive silver paste overflows from metal groove 7, also can get into the arc recess, has avoided conductive silver paste to overflow from metal groove 7 and produce the short circuit risk.

The method for packaging the infrared detector comprises the following steps:

s1, providing a packaging shell 3, forming a metal pad 4 in the packaging shell 3, forming a metal groove 7 on the inner bottom surface of the packaging shell 3, wherein four corners of the metal groove 7 are provided with arc-shaped grooves communicated with the metal groove 7, and the metal groove 7 is a mounting area of the infrared chip 1;

s2, providing an infrared chip 1, and then mounting the infrared chip 1 in the metal groove 7 by adopting conductive silver paste; the infrared chip 1 is a wafer, and is obtained by slicing the whole wafer into individual wafers, and performing professional cleaning on the individual wafers to remove foreign matters on the surfaces of the individual wafers;

s3, bonding the bonding pad on the infrared chip 1 with the metal bonding pad 4 in the packaging shell 3 by using the bonding wire 2;

and S4, providing an optical window 6, and sealing the opening of the packaging shell 3 by adopting the optical window 6 to form a vacuum sealed cavity, namely, packaging is realized.

In the packaging method, step S1 includes:

(1) presetting an installation area range of the infrared chip 1, wherein the installation area range corresponds to the position of a metal groove 7 with an arc-shaped groove communicated with the metal groove 7, setting the setting position and the pattern of a patterned metal pad 4, virtually reserving the position for forming the metal pad 4 in a purchased packaging shell 3, designing a steel mesh according to the shape of the required metal groove 7, forming a protective adhesive layer with the required shape in the area of the metal groove 7 to be formed in a screen printing or coating mode of the steel mesh, forming the protective adhesive layer in the position of each peripheral area at least surrounding the position of the patterned metal pad 4 in the packaging shell 3, and forming the protective adhesive layer on the peripheral surface of the packaging shell 3 to prevent the peripheral surface of the packaging shell 3 from being plated with metal when a metal layer is plated subsequently;

(2) placing the packaging shell 3 into an electroplating bath for electroplating to form a patterned metal bonding pad 4 at the setting position of the patterned metal bonding pad 4, forming a metal coating platform around the infrared chip mounting area, taking out the coating platform after the coating thickness reaches a set range, and removing the protective adhesive layer in the range of the preset infrared chip mounting area to obtain a groove with an arc-shaped groove;

(3) and (3) arranging a protective adhesive layer in other areas except the groove of the arc-shaped groove, then putting the protection adhesive layer into a plating bath for plating, controlling the plating time to form a gold surface and a height of the bottom surface of the groove, stopping plating after the plating layers of the bottom surface and the side wall of the groove meet requirements, removing the protective adhesive layer, and obtaining a metal groove 7 for mounting the infrared chip 1. The grooves formed by electroplating have strong adhesion force, low cost, random shape design and strong process controllability.

Step S2 specifically includes: conductive silver paste is coated at a set position of the metal groove 7, the infrared chip 1 is attached to the central area of the metal groove 7 by using the adhesive force of the conductive silver paste, and then the infrared chip 1 is attached to the metal groove 7 by baking and curing through a dust-free oven. In the step, in the specific operation process, when the conductive silver paste is coated, the camera is used for imaging and observing, the manipulator is controlled by the computer to electrically coat the conductive silver paste on the set position, the manipulator is controlled by the software algorithm of the computer to adsorb the infrared chip 1, the mechanical handle is controlled to place the infrared chip 1 on the designated area, and the infrared chip 1 is attached to the central area of the metal groove 7.

In step S4, the optical window 6 is an optical filter; the sealing is to perform vacuum welding on the optical window 6 and the top of the packaging shell 3.

In step S3, a Wire Bond process is used to connect the bonding pad on the infrared chip 1 and the metal bonding pad 4 in the package cavity together by using a bonding Wire (gold Wire) 2.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make many possible variations and modifications to the disclosed embodiments, or equivalent modifications, without departing from the spirit and scope of the invention, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention.