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Epoxy flow video capture for model validation

IP.com Disclosure Number: IPCOM000004754D
Publication Date: 2001-Apr-30
Document File: 12 page(s) / 7M

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method and equipment setup that enables the filming the flow of epoxy for model validation. Benefits include improved recipe development, improved detection of epoxy-underfill batches, increased knowledge about various aspects of the semiconductor production process.

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Epoxy flow video capture for model validation

Disclosed is a method and equipment setup that enables the filming the flow of epoxy for model validation. Benefits include improved recipe development, improved detection of epoxy-underfill batches, increased knowledge about various aspects of the semiconductor production process.

The disclosed method is a way to film and collect data during the flow of dispensed epoxy at a consistent and controlled temperature between two materials, for example, a substrate and an attached die, a bumped die and a glass slide, or two glass slides.

Key components (see Figures 1-7) of the disclosed equipment/process include:

A micro-camera to film the flow of epoxy between the substrate and the silicon

A boat with clamps and shims to hold the glass slides

A heat gun to maintain the epoxy flow temperature within spec limits

A dispenser to apply epoxy to the unit after the silicon is joined to the substrate

The method to mill the substrate itself down to the last layer before the solder bumps and after the silicon is joined to the substrate with the actual process

A computer-generated model predicts epoxy flow through bump configurations (actual or simulated) and pitches. The epoxy flow video capture method validates the model and supports the development process. The early creation of design rules helps to prevent costly redesigns and fixes. The new product introduction cycle is shortened due to easier determination of dispense weights and weight ratios, dispense line lengths/parameters, and dispense timing.

The disclosed method addresses several difficult problems:

Understanding the dynamics of bump pattern/pitch and epoxy flow until long after the silicon arrives for packaging

Viewing and understanding the effect of temperature on flow, material and batch properties, and substrate surface

Conventionally, these problems have been addressed using engineering resources and screening experiments.

The disclosed method provides visual information (see Figures 8-10) that can be analyzed quantitatively. Data is repeatable and reproducible. A best known method is available for the disclosed method and equipment set up design. Results include a process that provides flow distance data with a standard deviation of 15-20 mils for repeated measurements for snapshots at various times after dispense for an 800-mil flow distance (see Figure 11). This spread enables the viewing of many different signals.

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Disclosed anonymously