Product Code: PIC2008_P202

Localised Laser Joining of Glass to Silicon with BCB Intermediate Layer
Authors:
Qiang Wu, Heriot Watt University; Edinburgh Great Britain
C. Wang, Heriot Watt University; Edinburgh Great Britain
N. Lorenz, Heriot Watt University; Edinburgh Great Britain
S. Kloss, Heriot Watt University; Edinburgh Great Britain
A.J. Moore, Heriot Watt University; Edinburgh Great Britain
D. P. Hand, Heriot Watt University; Edinburgh Great Britain
Presented at PICALO 2008

Localised laser heating is an ideal solution to the problem of packaging micro-electro-mechanical-systems (MEMS) whilst maintaining a low device temperature to avoid changes in temperature-sensitive materials. In this paper we present localised laser bonding of glass to silicon by using a fibre-delivered high power laser diode array to cure an intermediate layer of the thermosetting polymer Benzocyclobutene (BCB). In our experiments, we use two ways to realize localised heating: one is by using scanning focused laser beam; the other is to use an axicon lens and followed a conventional lens to generate a focused ring. FE simulation indicates that provided sufficient heat sinking is provided at the rear of the device, both techniques result in very little in-process heating in the centre of the package, and this is confirmed by the use of a temperature-sensitive paint.