Screen printing method with different film thickness

Abstract

The invention relates to a method for screen printing materials with different film thicknesses in an integrated circuit, comprising the following steps: a. According to the layout of the original layer of emulsion film screen mask, around the position of the film layer that needs to be thickened, set A circle of square frames with a width of 1 to 2 mm forms a pattern layout of the emulsion film thickening; b. Reversely draws the above layout into a black and white negative film of the emulsion film thickening pattern; c. Paste the second layer of emulsion film on the first layer of emulsion film of the original screen mask, place the thickened graphic black and white negative film on the second layer of emulsion film layer, and form a thickened emulsion film graphic film after exposure and development layer; d. Use a thickened emulsion film screen mask to print conductive adhesive film layers or conductive tape film layers with different film thicknesses through a screen printing machine. The advantages of the present invention are as follows: the conductive paste or conductive adhesive film layers with different thicknesses are formed by one-time printing, which saves a lot of material costs, and the size and thickness of the film layer have good consistency in control, high processing precision, and low process difficulty.

Description

Technical field: [0001] The invention relates to the field of integrated circuit manufacturing, and particularly designs a method for screen printing materials with different film thicknesses in the integrated circuit. technical background: [0002] At present, materials suitable for screen printing include thick film electronic paste, conductive epoxy, etc. The existing technology is to use a screen mask for screen printing to produce the required material film layer, because the screen mask used The mesh number of the screen is the same, and the thickness of the emulsion film on the screen is also the same, so the thickness of the film layer of the material produced by screen printing is also the same. In general, this kind of screen mask can meet the needs of conventional circuit processing, but in special cases it cannot meet the processing requirements, as follows: [0003] 1. Thick film electronic paste: when there are conventional circuit traces and bonding areas on ...

AI Technical Summary

Problems solved by technology

In general, this kind of screen mask can meet the needs of conventional circuit processing, but in special cases it cannot meet the processing requirements, as follows:

[0003] 1. Thick film electronic paste: when there are conventional circuit traces and bonding areas on the same layer of conductive tape (the same thick film conductor material is printed at the same time), and there are component soldering areas and high-power wiring at the same time, Because the required film thickness of the material is different, conventional circuit traces and bonding areas require a film thickness of 40 μm to 50 μm, and component soldering areas and high-power wiring require a film thickness of 70 μm to 85 μm. At this time, the existing technology is Unable to meet processing requirements

At present, only the method of thickening (film thickness is controlled at 70 μm to 85 μm) can be used to make the thick film conductive paste layer, which wastes a lot of material costs

[0004] 2. Conductive epoxy: There are different types of bonding components required on hybrid integrated circuits, and the thickness of the conductive adhesive film required is also different. For example, the thickness of the conductive adhesive film for bare chip bonding is 20 μm to 30 μm, and chip devices The thickness of the conductive adhesive film for bonding is more than 50 μm, and the existing printing technology cannot meet the bonding requirements of different components

At present, the conductive epoxy layer can only be made by fully thinning (the film thickness is controlled at 20 μm to 30 μm). Later operators use manual dispensing to reinforce the end of the chip device. There are three types of reinforcement methods. Disadvantages: First, the manual dispensing takes a long time; second, it is prone to missing dispensing; third, the amount of manual dispensing cannot be controlled, resulting in poor consistency of circuit parameters.

Although this patent also achieves the printing requirements of different thicknesses, it requires double-layer mold opening and reverse printing (that is, the printing paste is first scraped and coated on the double-layer template, and then the circuit board is placed on the upper template. Print the graphics formed by the printing paste onto the circuit board), and cannot be applied to the screen printing of integrated circuits

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