Bipolar Isolation Trench Fill by Deposition and Reflow of Poly-P- Xylylene
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
This article relates to vertical isolation trenches which are filled with poly-p-xylylene (PPX). Fig. 1 shows a chemical vapor deposition (CVD) of a conventional insulating film 10. Note that the film 10 is deposited faster at the top of a trench 11 than at the bottom 12, such that the upper surface of the trench is closed off before it is completely filled. This results in the formation of a void 13. The use of PPX deposited by CVD results in an excellent dielectric film which will fill trenches without the void formation usually associated with CVD films. Fig. 2 shows PPX deposited in a trench 14 having negatively sloped sidewalls 15, such that voids (not shown) may be formed. After deposition, the wafer is heated to the melting point of PPX, causing the organic polymer to become viscous.