Atomic Bonded Thermal Matching Substrate for Sensor Warping

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Solution Overview

Problem

Conventional methods for altering the rate of thermal expansion of semiconductor substrates are inadequate, leading to thermal mismatch issues during hybridization, which can result in misalignment and poor image quality in sensor chip arrays, and are often time-consuming and costly due to the need for post-hybridization adjustments.

Innovation Solution

A composite semiconductor structure is formed using atomic bonds between a thermal matching substrate and a balancing substrate, allowing for wafer-level thermal expansion matching prior to hybridization, thereby ensuring that the first substrate expands and contracts at a rate equal to the second substrate, preventing warping and maintaining electrical contact across temperature changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional epoxy bonding is used to match thermal expansion rates, then thermal matching is achieved, but bond integrity is lost at elevated temperatures

Engineering Contradiction:

Improvebond integrityVSAvoidelevated temperature performance

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent changes the bonding mechanism from conventional epoxy bonding to atomic layer deposition (ALD) bonding, fundamentally altering the bonding parameters to achieve temperature-resistant attachment. The ALD process creates conformal atomic-layer bonds that maintain integrity at elevated temperatures where epoxy would fail.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure combining the first substrate, thermal matching substrate, and balancing substrate bonded through ALD. This multi-layer composite architecture with atomic-layer bonding provides both thermal matching capability and high-temperature bond integrity that neither material alone could achieve.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If thermal matching substrate is bonded using epoxy, then thermal expansion rate is altered, but alignment precision deteriorates due to warping

Engineering Contradiction:

Improvealignment precisionVSAvoidwarping

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

The patent applies local quality by introducing a balancing substrate with specific material properties on the opposite side of the thermal matching substrate. This local addition counteracts the warping forces generated by thermal expansion mismatch, maintaining overall planarity and alignment precision.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The balancing substrate acts as a counterweight to the thermal expansion forces. By positioning this substrate with appropriate mechanical properties on the opposite side of the thermal matching substrate, the patent creates a force balance that prevents warping and maintains alignment precision during temperature changes.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Reliability

If post-hybridization thermal matching adjustments are made, then thermal expansion matching is achieved, but manufacturing time and cost increase

Engineering Contradiction:

Improvethermal expansion matchingVSAvoidmanufacturing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary action by performing thermal matching substrate bonding via ALD before the hybridization process. This advance preparation ensures thermal expansion matching is already in place, eliminating the need for time-consuming post-hybridization adjustments and streamlining the overall manufacturing timeline.

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 the formation of sensor chip arrays with improved thermal matching and reduced costs by allowing for pre-hybridization thermal matching and maintaining alignment and electrical contact during elevated temperature processes, reducing the likelihood of misalignment and enhancing image quality.

Implementation Method 1

The thermal matching substrate is adapted to alter the rate of thermal expansion of the first substrate

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The composite semiconductor structure is formed by atomically bonding a first surface of a thermal matching substrate to a first surface of the first substrate

Methodology Applied

Scientific EffectAtomic bonding: Chemical Bonding

Data Source

PatentUS8154099B2Composite semiconductor structure formed using atomic bonding and adapted to alter the rate of thermal expansion of a substrate

Publication Date: 2012.04.10 RAYTHEON CO

AI summary

In certain embodiments, a method includes forming a composite semiconductor structure for altering a rate of thermal expansion of a first substrate. The composite semiconductor structure is formed by atomically bonding a first surface of a thermal matching substrate to a first surface of the first substrate, and atomically bonding a second surface of the thermal matching substrate to a first surface of a balancing substrate. The thermal matching substrate is adapted to alter the rate of thermal expansion of the first substrate and the balancing substrate is adapted to substantially prevent warping of the composite semiconductor structure.