High-Density Solder Interconnect Using Pre-Deposited Gap Control

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Solution Overview

Problem

Conventional solder jetting methods in hard disc drive systems often result in trajectory errors and solder ball deformation, leading to unintended solder contact with adjacent bond pads or open connections, particularly in high-density applications, where precise positioning is critical for accurate electrical connections.

Innovation Solution

A method involving the positioning of a suspension adjacent to a slider with a pre-deposited solder layer and applying energy, such as laser radiation, to melt and deform the solder, creating a solder joint between the slider and suspension, utilizing a predefined gap and potentially non-wettable surfaces to ensure accurate and controlled solder placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If solder jetting is used to provide electrical connection, then manufacturing efficiency is improved, but trajectory error and solder ball deformation occur leading to poor connection reliability

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidconnection reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The solder material is pre-deposited in a controlled manner onto the suspension component before assembly, establishing precise positioning and geometry in advance. This preliminary placement eliminates trajectory errors that occur during jetting and prevents deformation upon impact, while still enabling efficient manufacturing through the subsequent pick-and-place process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention replaces the jetting mechanical system with a pick-and-place system that uses suction cups for contactless handling. This substitution eliminates the mechanical trajectory errors and impact forces inherent in jetting, achieving both high manufacturing efficiency and connection reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If solder jetting is used for high density applications, then productivity is improved, but precision deteriorates due to trajectory error and deformation

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidsolder placement precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The solder material is pre-formed with precise geometry and positioning on the suspension component before assembly. This preliminary action establishes exact placement coordinates and maintains spherical integrity, eliminating both trajectory errors and impact deformation that plague jetting methods in high-density applications.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The jetting mechanical system is replaced with a pick-and-place system using suction cups for contactless manipulation. This substitution maintains manufacturing precision by eliminating mechanical trajectory errors and impact forces, while preserving high productivity through automated handling.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If pre-deposited solder material with predefined gap is used, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improvesolder placement precisionVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The solder material is pre-deposited with a predefined gap distance from the bond pad surface, establishing precise positioning in advance. This preliminary action simplifies the overall process by eliminating the need for complex real-time trajectory control and impact force management, while maintaining high manufacturing precision through controlled placement.

Inventive Principle:

Principle #10Preliminary action

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

This approach enables precise and accurate solder connections, reducing the likelihood of bridging or open connections, and allows for individual or simultaneous solder interconnects without impacting slider-to-suspension spacing, thereby enhancing the reliability of electrical connections in high-density data storage systems.

Implementation Method 1

The step of applying energy may include applying laser radiation to the solder material

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

applying energy to the solder material to melt the solder material and allow it to move toward and contact the lower surface of the slider

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS20240157457A1Process for high density solder interconnect

Publication Date: 2024.05.16 SEAGATE TECH LLC

AI summary

A method of interconnecting multiple components of an electrical assembly with a solder joint that includes the steps of positioning a suspension adjacent to a slider to provide a connection area between the suspension and the slider, wherein the suspension comprises a pre-deposited quantity of solder material with a height that provides for a predefined gap between a lower surface of the slider and an upper surface of the solder material, and applying energy to the solder material to melt the solder material and allow it to move toward and contact the lower surface of the slider.