A method for producing a silicon stack

Abstract

The invention discloses a production method of silicon stacks. The method comprises the steps that square crystal grains are cut by adopting a two-step method and pre-cutting in the thicken directionof silicon chips to form square crystal grains which are not completely cut, wherein the cutting depth of the silicon chips accounts for (3 / 5)-(4 / 5) of the total thickness of the silicon chips; N surfaces of the silicon chips which are pre-cut in the thickness direction are upward placed on crystal grain cracking paper, cutting cuts are placed upward and pressed slightly, so that the square crystal grains which are not completely cut are completely cracking. Then the crystal grains are placed into a suction cup for grain shaking, according to a strict dimension scale relation which is kept bythe size of soldering flakes and the size of the square crystal grains, filling is conducted according to a sequence of alternative filling of the soldering flakes and the crystal grains, scaling powder is evenly sprayed on the surfaces of welding boats, and the welding boats are subjected to low-temperature welding. According to the production method of the silicon stacks, alignment of the crystal grains in advance is not needed before welding, automatic alignment of the crystal grains after welding can be achieved, the production links are simplified, the welding temperature is lowered, theenergy is saved, the yield is high, the area of air holes is low, and the problem of sparse and loose welding is solved.

Description

Technical field [0001] The invention relates to a production process of a diode, in particular to a production method of a silicon stack. Background technique [0002] At present, silicon stack welding, square grain welding, alignment and welding alignment are difficult problems. The current general method is to use the process of welding and stacking the whole silicon wafer and then cutting it. The welding fixture is bulky and complicated, and because the whole silicon wafer is in the previous Due to the deformation caused by the diffusion process, the large solder pieces are unevenly distributed after being melted at high temperature, resulting in a high rate of damage during the cutting process. The small cells after the cut have to be refilled to solder the leads. The secondary soldering causes secondary damage to the grains and the number of soldering times. The more the damage, the more serious. The above process is not only complicated in process, complicated in equipment...

AI Technical Summary

Problems solved by technology

The highest welding temperature in this patent is 385°C. If the welding temperature is too high, it will easily lead to a high proportion of welding pores < 20%, a low yield rate (less than 90%), and a waste of energy.

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