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Method for adding a dummy copper pattern to the side rail of a BGA laminated substrate

IP.com Disclosure Number: IPCOM000022676D
Publication Date: 2004-Mar-25
Document File: 3 page(s) / 404K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for adding a dummy copper pattern to the side rail of a ball grid array (BGA) laminated substrate. Benefits include improved yield.

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Method for adding a dummy copper pattern to the side rail of a BGA laminated substrate

Disclosed is a method for adding a dummy copper pattern to the side rail of a ball grid array (BGA) laminated substrate. Benefits include improved yield.

Background

         Mold flashing and solder-resist cracking can occur during assembly due to severe substrate strip warpage. Mold flashing is the leaking of liquid mold material from the lower thickness area at the mold cavity. Solder-resist cracking enables solder to flow into areas where it should not flow. Both problems result in yield loss.

Description

The disclosed method adds dummy copper patterns to the side rail of a BGA laminated substrate to balance substrate thickness and reduce mold flashing and solder-resist cracking. Almost all BGA laminated substrates require dummy copper patterns to improve yield.

The key elements of the disclosed method include:

•         Handling techniques to reduce the solder mask cracking by minimizing warpage of the substrate during the assembly process steps, such as molding and solder ball attachment reflow

•         Minimizing the variance of substrate thickness within a substrate strip during the molding process through the use of dummy copper patterns to the side rail of a BGA laminated substrate (see Figures 1, 2, and 3)

Advantages

         The disclosed method provides advantages, including:

•         Improved yield due to preventing the BGA substrate warpage that causes solder mask cracking and mold flashing

Fig. 1

Fig. 2

Fig....