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Sputtering of Metal On Polymers

IP.com Disclosure Number: IPCOM000062727D
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Morrison, GD: AUTHOR [+3]

Abstract

In sputtering Cu on polyimide at high rates, polyimide has been seen to develop microcracks and to have poor adhesion. The microcracks are believed to be due to excessive heating at the surface of the polyimide and/or ionic and electronic bombardment due to the plasma. The loss of adhesion of the metal to the polyimide is believed to be due to changes in the surface chemistry of the polyimide caused by the ionic bombardment.

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Sputtering of Metal On Polymers

In sputtering Cu on polyimide at high rates, polyimide has been seen to develop microcracks and to have poor adhesion. The microcracks are believed to be due to excessive heating at the surface of the polyimide and/or ionic and electronic bombardment due to the plasma. The loss of adhesion of the metal to the polyimide is believed to be due to changes in the surface chemistry of the polyimide caused by the ionic bombardment.

A solution to the above problem is shown in Fig. 1, as implemented in a typical sputtering system. A perforated grid 10, kept at ground potential, is introduced between the target 11 and the substrate 12 on pallet 13. This creates a region free of electric field between the grid 10 and the pallet 13, thus keeps the substrate 12 away from the plasma 14. The deposition will proceed through the perforations in the grid. For this reason, a grid 10 with a high percentage effective area e.g. 56.25% is to be used (as shown in Fig. 2).

In continuous sputtering systems where the pallet 13 moves under the target 11, the idea may be implemented in the form of a grid 10 stationary relative to the target or in the form of a "cage" stationary relative to the pallet.

Experiments have been done with "cage" and a threefold increase in adhesion of Cu to polyimide has been measured. No cracking of the polyimide has been observed.

The above idea can be used on other polymers such as epoxies, and also in semiconductor applications...