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Alternative Epoxy Dispensing System

IP.com Disclosure Number: IPCOM000233359D
Publication Date: 2013-Dec-10
Document File: 3 page(s) / 340K

Publishing Venue

The IP.com Prior Art Database

Abstract

Conventional die bond epoxy dispensing system has always been the bottle neck that drastically reduces production through put at the IC assembly die bond process step and can be highly unreliable leading to high yield losses. A simpler, very reliable, and faster process is introduced in this disclosure.

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Document Title 

Alternative Epoxy Dispensing System

 

Abstract 

Conventional die bond epoxy dispensing system has always been the bottle neck that drastically reduces production through put at the IC assembly die bond process step and can be highly unreliable leading to high yield losses. A simpler, very reliable, and faster process is introduced in this disclosure.

Body 

We propose a cylindrical rolling element that transfers epoxy from an epoxy well above the roller on to the die pad surface as a continuous sheet of liquid as the roller rolls across the die pad. The device is analogous to a ballpoint pen where the ball transfers ink to the surface of the paper as it rolls; the ball re-sets when it rolls in the ink well. In the proposed device, instead of a just line, a precise area of coverage can be controlled with the width of the cylindrical rolling element, and the length of the line rolled.  Further, epoxy BLT can be preset by adjusting a gap between the exiting surface of the roller and the roller sheath.

Conventional dispensing systems include an epoxy writer, a shower head printer, and epoxy pad printing. Epoxy writers are slow as they need to draw the print patterns in its full trajectory.  For large die size, drawing the epoxy print pattern takes about 60% of the total die bond cycle time.  The actual placement of dies onto lead frames or substrates has traditionally been very fast but the overall throughput suffers due to the slow epoxy pattern printing process.  The other options are to use showerhead printers, but past experience revealed this as a highly unreliable and cumbersome process.  Voids can be introduced when the drawn lines or the showerhead printed dots merged under the placement of the die. Showerhead printers are also pr...