Tailoring single-layer ceramic capacitors to the elongated lengths of GaN die
When wire-bonding GaN die to single-layer ceramic capacitors, the high power output of the GaN die requires multiple wires to be used for current handling, which increases the inductive impedance of the module. Capacitors are then used to cancel the inductive component of the impedance and se the module impedance to a common value (typically 50 ohms) at the frequency of interest. As GaN die have an elongated structure, the length of the single-layer ceramic capacitor also had to be long to match the GaN chip. However, typically single-layer ceramic capacitors come in square form factors and have aspect ratio limitations.
▲Conventionally, multiple capacitors are required to be arranged parallel to GaN die.
High aspect ratio rectangular capacitors for reducing component count
Tecdia manufactures rectangular single-layer ceramic capacitors that fit perfectly to the sizes of GaN die. Conventionally, capacitor aspect ratio was generally limited to 1:3, but Tecdia developed reliable process control to realize capacitors with 1:6 aspect ratio (typical), or up to 1:10 upon request. This eliminates the need to arrange multiple single-layer ceramic capacitors within the module, reducing both the number of parts needed and the minimizing die attach mounting processes.
Tecdia listens to customer needs to develop precision design capabilities
As single-layer ceramic capacitors become elongated, various manufacturing issues may be encountered, such as the cracking during dicing in the chip-forming process and peeling of the gold layers. Tecdia countered these issues by developing a setback using our unique manufacturing technology that makes chips resistant to breakage during dicing. Furthermore, since the elongated product is more prone to warping or cracking due to thermal expansion, we purposely designed our caps with gold layers on the back side, after hearing details of our customer’s application.
The troubles of mounting multiple single-layer ceramic capacitors in a row have been eliminated, shortening the die attachment process and reducing costs.
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