Hybrid Solder Grid Array for Testing-Stable Die Package Attachment

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Solution Overview

Problem

Low-temperature solder materials used in electronic devices are prone to deformation and damage during electrical testing, leading to issues like solder ball bridging, socket contamination, and electrical failure, while preservative-coated copper pads make electrical testing impractical due to non-conductivity.

Innovation Solution

A hybrid solder joint interface is formed with a first structure on the die package substrate using a high-temperature solder material to withstand electrical testing and a second structure using low-temperature solder material for warpage benefits, comprising a thin solder layer and an interconnect ball.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If low-temperature solder material is used, then warpage is reduced during reflow, but the solder material is prone to deformation and damage during electrical testing

Engineering Contradiction:

Improvereflow temperatureVSAvoidsolder bump integrity

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The solder joint is segmented into two distinct structures: a thin solder layer made of high-temperature solder material that withstands electrical testing, and an interconnect ball made of low-temperature solder material that provides warpage benefits during reflow. This segmentation allows each material to perform its optimal function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the solder joint have different material properties: the upper portion (thin solder layer) uses high-temperature solder material for testing durability, while the lower portion (interconnect ball) uses low-temperature solder material for reflow performance. This local differentiation resolves the contradiction between testing reliability and reflow warpage control.

Inventive Principle:

Principle #3Local quality

2Reliability

If preservative-coated copper pads are used, then oxidation is prevented, but electrical testing becomes impractical due to non-conductivity

Engineering Contradiction:

Improvepad oxidation resistanceVSAvoidelectrical testing feasibility

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Electrical testing is performed on the thin solder layer before the interconnect ball is formed. This preliminary action allows testing to occur when the pad surface is accessible and conductive, avoiding the need to test through the preservative coating while still enabling complete electrical validation before final assembly.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If high-temperature solder material is used, then electrical testing durability is improved, but warpage control during reflow is worsened

Engineering Contradiction:

Improvetesting withstand capabilityVSAvoidreflow warpage

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The solder joint is divided into two functional segments: a thin solder layer using high-temperature solder material for testing durability, and an interconnect ball using low-temperature solder material for warpage control during reflow. This segmentation enables both high testing reliability and effective warpage management.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the temperature parameter characteristics by using different solder materials with different melting points in different locations. The thin solder layer uses high-temperature material (e.g., SAC305 with melting point around 220°C) for testing, while the interconnect ball uses low-temperature material (e.g., Sn-Bi alloy with melting point below 150°C) for reflow, thereby resolving the contradiction between testing durability and warpage control.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The hybrid solder joint effectively withstands electrical testing conditions without warping, ensuring reliable electrical and mechanical connections between the die package and circuit board.

Implementation Method 1

Methodology Applied

Scientific EffectSoldering: Soldering

Data Source

PatentUS12557683B2Solder grid array for attachment of a die package

Publication Date: 2026.02.17 INTEL CORP

AI summary

A die package comprises a substrate comprising a solder pad element, a semiconductor die coupled to the substrate, a solder layer comprising a first solder material deposited on the solder pad element, the first solder material having a first melting temperature, and an interconnect ball comprising a second solder material deposited on the solder layer, the second solder material having a second melting temperature that is less than the first melting temperature.