A method for eutectic welding to solve pind detection

Abstract

The invention discloses a method for eutectic welding to solve unqualified PIND detection, which belongs to the technical field of aerospace microelectronic packaging. In the heating and preheating stage, the reciprocating cycle of vacuuming and nitrogen filling is adopted to reduce the oxygen and water vapor content in the furnace, avoiding Oxidation of the alloy during the eutectic process. The graphite plate is heated by infrared to make the welding surface temperature uniform. After heating up to the welding temperature, the heat preservation welding is used; the controllable atmosphere eutectic furnace is used, hydrogen is used as the reducing agent and flux, and tin-silver-copper solder is used. Instead of tinning on the substrate, eutectic welding between the substrate and the shell is carried out, which reduces the free moving particles produced by the welding between the film-forming substrate and the shell, and optimizes the previous soldering method of tinning on the substrate; by adopting a controllable The method of atmosphere eutectic furnace realizes the welding between the ceramic substrate and the shell, eliminates the use of traditional flux, effectively reduces the number of free particles caused by flux residue, and makes the packaged product successfully pass PIND detection.

Description

technical field [0001] The invention relates to the technical field of aerospace microelectronic packaging, in particular to a method for solving PIND detection by eutectic welding. Background technique [0002] Thick-film hybrid integrated circuits are widely used in various military and aerospace electronic equipment, and it has a very high assembly density and reliability. Thick-film hybrid integrated circuits not only include various externally mounted resistors and capacitors, but also mount various chips. Among them, power-type thick-film circuits use part of the power chips, which will generate a lot of heat during operation. [0003] In the absence of a special backside cooling device, the substrate is required to have a certain heat dissipation interface, which requires the soldering between the substrate, the housing base and the chip to have good thermal conductivity. In the power type thick film circuit, in order to complete the welding of the film-forming subst...

AI Technical Summary

Problems solved by technology

The bonding between the ceramic substrate and the base is carried out by hanging tin welding. Not only the welding strength is high, but also the contact surface between the substrate and the shell is large and the heat dissipation effect is good. However, the use of traditional flux will make the welding interface, There are a large number of freely moving particles around the substrate, which seriously affects the subsequent PIND detection and reduces the reliability of the product

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