Guard Ring Wiring for IC Moisture Protection

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Solution Overview

Problem

The existing guard ring structures for large scale integrated circuit chips suffer from degraded moisture-proof performance when a part of the guard ring is cut off to accommodate test wiring, leading to potential contamination from moisture and ions during the dicing process.

Innovation Solution

The solution involves separating the uppermost-layer wiring within the guard ring from the test lead-out wiring outside the guard ring, allowing the conductive piece to connect through a conductive via within the guard ring without needing a cutout, thereby maintaining moisture-proof performance even when the conductive piece is exposed at the dicing surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a part of the guard ring is cut off to accommodate test wiring, then the test wiring can be connected to the semiconductor circuit, but the moisture-proof performance of the guard ring is degraded

Engineering Contradiction:

Improvetest wiring connectionVSAvoidmoisture-proof performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent divides the wiring structure into two separate parts: the guard ring wiring that remains intact to maintain moisture protection, and the test lead-out wiring that is exposed at the dicing surface for testing purposes. This segmentation allows the test wiring to connect to the semiconductor circuit through a conductive via without compromising the continuity of the guard ring structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a conductive via as an intermediary element that connects the test lead-out wiring to the uppermost-layer wiring within the guard ring. This intermediary allows electrical connection while maintaining the physical integrity and moisture-proof function of the guard ring structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the guard ring structure is maintained intact, then moisture-proof performance is preserved, but test wiring cannot be connected to the semiconductor circuit

Engineering Contradiction:

Improvemoisture-proof performanceVSAvoidtest wiring connection

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes the vertical dimension by using a conductive via to connect the test lead-out wiring (at the dicing surface level) to the uppermost-layer wiring (within the guard ring structure). This vertical connection allows test wiring access without requiring horizontal cuts in the guard ring.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Productivity

If the conductive piece is exposed at the dicing surface, then collective inspection of semiconductor circuits on wafer is enabled, but contamination from moisture and ions may occur

Engineering Contradiction:

Improvecollective inspection efficiencyVSAvoidcontamination from moisture and ions

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different functional qualities to different locations: the guard ring structure maintains its moisture-proof quality to prevent contamination, while the test lead-out wiring at the dicing surface is intentionally exposed to enable testing. The conductive via connects these two regions, allowing inspection functionality without compromising the protective quality of the guard ring.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10026699B2Integrated circuit chip and integrated circuit wafer with guard ring

Publication Date: 2018.07.17 SYNAPTICS INC

AI summary

A large scale integrated circuit chip includes a semiconductor circuit having a multilayered wiring structure, a metal guard ring surrounding the semiconductor circuit, and a plurality of external connection terminals, on a semiconductor circuit. The plurality of external connection terminals connect to an uppermost-layer wiring of the multilayered wiring structure and are exposed on a surface of the large scale integrated circuit chip. A predetermined external connection terminal conducts to a predetermined wiring through a conductive via within the guard ring and conducts to a conductive piece through another conductive via outside the guard ring. One side of the external connection terminal extending over the guard ring connects to the conductive piece, and the other side of the external connection terminal connects to the uppermost-layer wiring within the guard ring. Thus, a cutout part is not necessary in the guard ring.