US 11,153,976 B2 · Implementing IR reflective mask to minimize CTE mismatch between laminate and PTH copper

Abstract

A method and structure are provided for implementing manufacture of a printed circuit board (PCB) with one of an infrared (IR) reflective mask or a novel solder mask to minimize coefficient of thermal expansion (CTE) mismatch between PCB laminate and plated through hole (PTH) copper. At least one of an IR-reflective mask and a solder mask composition for use in IR reflow processes is created such that radiant heat is reflected away from the major portion of the PCB yet permitted to impinge upon the PTHs. The copper within the PTH expands due to radiant heating while the bulk laminate expansion is significantly reduced due to the reflected IR radiation. Consequently, the CTE mismatch is minimized and tensile strain of the copper in the PTH is reduced, providing enhanced reliability.

Claims17

Dependent claims

A method for implementing enhanced manufacture of a printed circuit board (PCB) to minimize coefficient of thermal expansion (CTE) mismatch between PCB laminate and plated through hole (PTH) copper comprising:

providing a photomask;
etching a pattern onto the photomask, wherein the pattern defines regions for a plated through hole (PTH) copper to extend through the PCB and regions that are not for the PTH copper to extend through the PCB;
forming an IR-reflective mask, wherein the forming comprises:
coating the regions that are not for the PTH copper to extend through the PCB with an IR-reflective coating;
and
applying the IR-reflective mask to the PCB for IR reflow processes.

3 more elements

Dependencies are inferred from the claim text.

Implementing IR reflective mask to minimize CTE mismatch between laminate and PTH copper

Life of this patent

Implementing IR reflective mask to minimize CTE mismatch between laminate and PTH copper

Life of this patent

Abstract

Claims17