Semiconductor Die Alignment via Spatial Interference Patterns

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Solution Overview

Problem

Current methods for aligning semiconductor dies for capacitive inter-chip communication are challenging due to thermal expansion, mechanical vibrations, and manufacturing perturbations, leading to residual misalignment and inefficient communication, with existing measurement techniques being complex, slow, and inaccurate, especially for small misalignment values.

Innovation Solution

A method that determines misalignment using spatial beat frequencies from signals transmitted and received through arrays of proximity connectors, leveraging spatial interference patterns to calculate angular and translational misalignment, allowing for improved alignment and communication via capacitive, optical, inductive, or conductive means.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If mechanical mounting structures with self-alignment are used, then ease of assembly is improved, but measurement precision deteriorates due to residual misalignment from thermal expansion and mechanical vibrations

Engineering Contradiction:

Improveease of assemblyVSAvoidalignment measurement precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical alignment measurement methods with optical interference patterns. By using optical fields instead of mechanical contact methods, the system achieves higher measurement precision that is not affected by mechanical vibrations or thermal expansion, directly resolving the contradiction between ease of mechanical assembly and measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces optical interference patterns as an intermediary medium to measure misalignment. These patterns serve as a mediator between the mechanical mounting structure and the alignment measurement, allowing precise detection of residual misalignment without being affected by the mechanical system's limitations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If existing capacitance-based measurement techniques are used, then device complexity is reduced, but measurement precision deteriorates for small misalignment values due to noise and instrument limitations

Engineering Contradiction:

Improvemeasurement system complexityVSAvoidsmall misalignment detection precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces electrical capacitance measurement with optical interference measurement. The optical method provides superior precision for detecting small misalignment values because optical interference patterns can resolve sub-micron displacements, overcoming the noise and resolution limits of electrical measurement instruments while maintaining relatively simple implementation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If capacitive coupling with dense signal lines is used, then integration density is improved, but productivity deteriorates due to communication bottlenecks in inter-chip signaling

Engineering Contradiction:

Improvesignal line integration densityVSAvoidinter-chip communication throughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent makes the proximity connectors universal by enabling them to serve dual functions: maintaining dense electrical signal routing for high integration density while simultaneously providing optical interference measurement capability for alignment verification. This multi-functionality resolves the contradiction by allowing the same structure to support both high-density communication and precise alignment measurement.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 accurate and efficient alignment determination, reducing communication bottlenecks and power consumption by facilitating precise alignment between semiconductor dies, even under small misalignment conditions, and allowing for continuous or intermittent steering of electrical signals.

Implementation Method 1

A spatial beat frequency is determined from the received signals. The spatial beat frequency corresponds to misalignment-induced aliasing of spatial frequencies associated with the first subset of the array of proximity connectors and the second subset of the array of proximity connectors.

Methodology Applied

Scientific EffectInterference: Interference

Data Source

PatentUS7292050B1Measuring rotational misalignment using spatial interference patterns

Publication Date: 2007.11.06 ORACLE AMERICAN INC

AI summary

A method for determining misalignment between two semiconductor dies is described in which signals are transmitted through a first subset of an array of proximity connectors that are proximate to a surface of one of the semiconductor dies and received through a second subset of an array of proximity connectors that are proximate to a surface of the other semiconductor die. A spatial beat frequency is determined from the received signals. This spatial beat frequency corresponds to misalignment-induced aliasing of spatial frequencies associated with the first subset of the array of proximity connectors and the second subset of the array of proximity connectors. The misalignment is then determined using the spatial beat frequency.