Abstract: A power module is provided that may include a first metal-clad substrate, a chip located on a side of the first metal-clad substrate, and first solder located between the first metal-clad substrate and the chip. A first metal layer is disposed on a surface that is of the first metal-clad substrate and that faces the chip, and the first metal layer includes a groove and a blocking part. A first thickness of the first metal layer is less than a second thickness. The first thickness is a thickness of at least a part of an area in the blocking part, and the second thickness is a thickness of the first metal layer in an area other than the groove and the blocking part. The blocking part is located between the chip and the adjacent groove, and is configured to prevent the first solder from overflowing into the groove.

Abstract: One embodiment of the present invention provides a system that determines an assist feature placement within a post-optical proximity correction (post-OPC) mask layout. During operation, the system receives a set of target patterns which represent a set of polygons in a pre-OPC mask layout. The system then constructs a focus-sensitive cost function based on the target patterns, wherein the focus-sensitive cost function represents an amount of movement of post-OPC contours of the target patterns in response to changes in focus condition of the lithography system. Note that the contours of the target patterns substantially coincide with the edges of set of the polygons. Next, the system computes a cost-covariance field (CCF field) based on the focus-sensitive cost function, wherein the CCF field is a two-dimensional (2D) map representing changes to the focus-sensitive cost function due to an addition of a pattern at a given location within the post-OPC mask layout.