Chapter 9: Tools
9-3: Electrical Rule Checking (ERC)
9-3-1: Well and Substrate Checking

To check the well and substrate layers, use the Check Wells command (in menu Tools / ERC). This does a more thorough job of checking the layers than the design-rule checker.

After analysis is done, you can review the errors by typing ">" to see the next error and "<" to see the previous error. You can also see the list of errors in the cell explorer (see Section 4-5-2).

You can control the Well Checker with the Well Check Preferences (in menu File / Preferences..., "Tools" section, "Well Check" tab).

Figure 9.15

The Well Checker makes sure that there are well contacts in every area of well. The dialog allows you check for just 1 well contact in each cell, or not to check for contacts at all.

The Well Checker also checks that there is a connection to power and ground in the appropriate places. You can disable these checks in the "Well Check" dialog.

An additional well check is to find the farthest distance from a substrate contact to the edge of that area. This check takes more time to do, and so it can be disabled.

The Well Checker can check spacing rules between well areas. Although this is generally the domain of the Design Rule Checker (DRC), it can be requested here by checking "Check DRC Spacing Rules for Wells". Since the well checker has not been designed for DRC purposes, the algorithm is not efficient and therefore the option is off by default.

Finally, the Well Checker is able to use multiple processors to speed up its task. This can be disabled, or the number of processors can be reduced with the "Use multiple processors" checkbox and field.

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