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An alternative method to measure burr height.

IP.com Disclosure Number: IPCOM000014908D
Original Publication Date: 2003-Jan-03
Included in the Prior Art Database: 2003-Jun-20
Document File: 4 page(s) / 172K

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The present invention provides an alternate method to measure burr height that is created by a mechanical drill process.

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An alternative method to measure burr height.

  The present invention provides a process for mechanical drilling of 1 and 2-oz Cu power planes for new products. The mechanical drill process, though very carefully controlled, always leaves some level of burr height on the exit side of the Cu power planes. The burr height is one of the control parameters needed to obtain higher yield of the final product, since a burr is a potential source for electrical shorting.

Currently, a defined number of coupons from a predefined plane, taken from a drilled stack, are cross-sectioned, then under a high magnification microscope, the burr height will be measured. If the burr height is over a certain limit value, the whole stack of panels will be scrapped.

This cross-sectioning method is costly and time consuming. Accordingly, we propose an alternate method to measure burr heights quickly and accurately.

A coupon is glued on a flat surface, preferably a 1x3 inch piece of glass, with the exit drilled side exposed (Figure 1). The preferred glass has a thickness of 1/32 inches. The coupon/glass is put on a moving table of a high magnification microscope (at least 400X) which has the ability to measure in the z-direction. The scope's table is then moved in x and y-directions to a reference location. Adjust the scope's height to focus on the surface of the Cu plane. Set this height as zero reference. Adjust the scope's height to focus on the top of the burr. Read the height value from...