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Method for a substrate with a recessed pad

IP.com Disclosure Number: IPCOM000083124D
Publication Date: 2005-Feb-28
Document File: 3 page(s) / 73K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a substrate with a recessed pad. Benefits include improved functionality, improved reliability, improved throughput, and improved yield.

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Method for a substrate with a recessed pad

Disclosed is a method for a substrate with a recessed pad. Benefits include improved functionality, improved reliability, improved throughput, and improved yield.

Background

      The occurrence of capacitor rework due to shifting and skew, result in high process throughput time. Rework is the major bottleneck for the subsequent test module. When a single unit has chip capacitor rejects, the whole manufacturing lot is held until the lot has completed rework. On average, one unit takes up 2 minutes for an operator to perform the rework.

      Capacitor shifting and skew is a major cause of fallout after thermal reflow. Capacitor shifting is when both terminal electrodes of the component are bonded with one side of the printed circuit board pad. Skew is when the component is tilted at an angle and is contacted with both surface of the pads.

      Conventionally, the solder paste (TSP) is higher than the solder resist gap (TSR1), which can be expressed as TSP>TSR1. During the reflow process, the chip capacitor floats on the solder paste. The capacitor is at the same surface and has a tendency to move, especially when the surface tension is not equal (F1 ≠ F2, where F is the imbalance force).

      The conventional solution does not take into account the depth of solder resist in relation to the substrate gold pad.

General description

      The disclosed method is a substrate with a recessed pad, to stabilize capacitor performance, to prevent shifting and/or skewing, during temperature reflow. The method standardizes the design rule for the substrate and the thickness from the solder resist layer to the pad.

Advantages

              The disclosed method provides advantages, including:
•             Improved functionality due to standardizi...