Substrate structures and methods of manufacture
View Patent ↗A power electronic substrate includes a metallic baseplate having a first and second surface opposing each other. An electrically insulative layer also has first and second surfaces opposing each other, its first surface coupled to the second surface of the metallic baseplate. A plurality of metallic traces each include first and second surfaces opposing each other, their first surfaces coupled to the second surface of the electrically insulative layer. At least one of the metallic traces has a thickness measured along a direction perpendicular to the second surface of the metallic baseplate that is greater than a thickness of another one of the metallic traces also measured along a direction perpendicular to the second surface of the metallic baseplate. In implementations the electrically insulative layer is an epoxy or a ceramic material. In implementations the metallic traces are copper and are plated with a nickel layer at their second surfaces.
1. A method of forming a direct bonded copper (DBC) substrate for a power electronic, comprising:
coupling a first surface of a ceramic layer to a second surface of a metallic baseplate, the ceramic layer having a second surface opposing the first surface;
coupling a first surface of a copper layer with the second surface of the ceramic layer, the first surface of the copper layer having a pattern comprising a first thickness and a second thickness greater than the first thickness, the first thickness and the second thickness both measured perpendicularly to the first surface of the ceramic layer; and
forming traces in the copper layer by etching through the copper layer at the first thickness and etching through the copper layer at the second thickness, wherein the traces comprise two different trace thicknesses, where the trace thicknesses are measured perpendicularly to the first surface of the ceramic layer.
2. The method of claim 1 , wherein the second surface of the ceramic layer comprises a pattern complementary to the pattern of the first surface of the copper layer.
3. The method of claim 1 , further comprising plating a layer of nickel onto the second surface of the copper layer, and wherein forming traces in the copper layer comprises etching through the layer of nickel.
4. The method of claim 1 , wherein etching through the copper layer at the first thickness and etching through the copper layer at the second thickness comprises coupling a first layer of photoresist to the second surface of the copper layer, forming a pattern in the first layer of photoresist, etching the copper layer at the first thickness at a space in the pattern in the first layer of photoresist, removing the first layer of photoresist, coupling a second layer of photoresist to the second surface of the copper layer, forming a pattern in the second layer of photoresist, etching the copper layer at the second thickness at a space in the pattern in the second layer of photoresist, and removing the second layer of photoresist.