Homework 2 Notes
last update - 14:18, 29 Jan 2001

A new pdf of homework 2 with improved pictures has been posted.


Beware that the photocopier makes the oxide light shading disappear and check the online version to see the diffused resistor layout for Problem 2.3.

You will need to use your knowledge of how contacts are built to interpret the layouts in HW#2. The basic idea is the underneath layer being contacted needs to provide a landing pad that is about 3 times the size of the contact (small black square). The underlying layer is covered with an insulator and the contact mask then creates a hole the at the location of the small black square. The material making contact from above then fills the hole but needs to cover an area about 3 times larger than the hole in case there is misalignment.

The above means that for every contact there must be an underlying conducting material with size 3X the hole and a covering conducting material that is 3x the hole in size.

Unfortunately the word processors do allow both of the conducting layers to be viewed simultaneously.


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