Browse Prior Art Database

Thin Board Apparatus to Measure Via Plug Fill Percent

IP.com Disclosure Number: IPCOM000010070D
Publication Date: 2002-Oct-16
Document File: 3 page(s) / 45K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that uses a thin board apparatus which can be fully or partially processed in the same manner as a PCB, with a thickness that matches the via fill percent to be tested in PCB boards. Benefits include correcting filling process errors before the plugging material has cured.

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Thin Board Apparatus to Measure Via Plug Fill Percent

Disclosed is a method that uses a thin board apparatus which can be fully or partially processed in the same manner as a PCB, with a thickness that matches the via fill percent to be tested in PCB boards. Benefits include correcting filling process errors before the plugging material

has cured.

Background

Currently, there are two ways to measure the plugging material fill percent:

  • by taking a cross-section of the PCB
  • by examining the color of the plug under a lamp

The cross section method is an end-product inspection and cannot be used to correct the process (i.e. it is used only to reject product). The color method is qualitative rather than quantitative, and relies on operator judgment and experience.

General Description

A specific amount or depth of plugging material is desired in vias. The disclosed method uses a board that is the same thickness as the� desired depth or fill percent in the PCB; if the PCB goes through the plugging process and material comes out the vias on the bottom, then the process will deposit the thickness of the board of plugging material (see Figure 1). The plugging material leaves a mark on the marking sheet, indicating that the plugging material has filled the via to the depth of the board (see Figures 2 and 3). If plugging material is not visible on the marking sheet, then the process is not depositing the correct amount of material in the vias (see Figure 4). With the disclosed method,� PCB...