Die Pad With Raised Portion And Recessed Area For Die Attach Control
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Solution Overview
Problem
Conventional semiconductor packaging substrates face challenges in controlling the volume of die attach material, leading to issues such as under or over dispense, which can result in wire bond failures between the semiconductor die and package substrates or lead frames.
Innovation Solution
The design of substrates with a die pad featuring an outer raised flat portion and a recessed portion allows the semiconductor die to sit directly on the raised flat portion without intervening die attach material, addressing the control issues and preventing material bleeding or tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a planar die attach surface is used, then the substrate structure is simple and easy to manufacture, but the volume of die attach material cannot be controlled, leading to under or over dispense
Solution Approach 1:
The patent transitions from a two-dimensional planar die attach surface to a three-dimensional non-planar surface with raised outer portions and recessed inner portions. This dimensional change enables precise control over die attach material volume by confining the material within the recessed area, preventing both under and over dispense while maintaining manufacturing feasibility.
Solution Approach 2:
The die attach surface is designed with different local characteristics: raised outer portions that prevent material overflow and recessed inner portions that contain and control the die attach material volume. This local differentiation allows precise material control in critical areas while maintaining overall structural simplicity.
2Strength
If die attach material is used to bond the semiconductor die, then the die can be securely attached to the substrate, but the material may bleed laterally and cover the substrate pads, causing wire bond failures
Solution Approach 1:
The raised outer portions of the die attach surface create physical barriers that prevent die attach material from flowing laterally onto the substrate pads before the bonding process completes. This preliminary preventive structure eliminates the risk of material bleeding causing wire bond failures, ensuring both strong attachment and reliable electrical connections.
3Adaptability or versatility
If larger semiconductor dies are used, then the device functionality is enhanced, but the package footprint increases
Solution Approach 1:
The patent changes the geometric parameters of the die attach surface by introducing raised outer portions and recessed inner portions. This parameter modification allows larger semiconductor dies to be mounted within the same package footprint by optimizing the use of available space and preventing material overflow that would otherwise require larger clearance areas.
Data Source
AI summary
A method of forming an electronic assembly includes dispensing a die attach material on a substrate into a recessed portion that includes an inner recessed portion of including a die pad. The die attach material is not dispensed on an outer raised flat portion of the die pad. A semiconductor die is attached directly on the outer raised flat portion and affixed to the die pad with said die attach material in said interior recessed portion but not on said outer raised flat portion.