Improved C4 Reliability Using Low Modulus Dielectric Layer
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
A reduction in controlled collapse chip connector (C4) solder strain can be achieved by using a low modulus dielectric material as a mounting surface for semiconductor chips. Therefore, the C4 reliability can be improved by using a low modulus dielectric material next to the C4. The thermal mismatch between a ceramic carrier and a silicon chip has long been known. The application of a thin layer (1-2 mils) of a low modulus material, e.g., TEFLON*, to a ceramic carrier significant (Image Omitted) ly reduces C4 solder strain, as shown in Fig. 1. The dielectric modulus has a logarithmic relationship to the percentage of solder strain shown by the curve. This curve is drawn from calculated values of solder strain. Plotted in Fig.