TSV Test Unit Detecting Copper Ion Migration
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Solution Overview
Problem
The challenge in semiconductor devices is the deterioration of electrical characteristics and reliability due to copper ions migrating from Through Silicon Vias (TSVs) during the fabrication process, leading to potential short-circuiting and defective memory elements, which are not immediately detectable until after packaging.
Innovation Solution
A semiconductor device with a test unit is integrated in the Keep Out Zone (KOZ) adjacent to the TSV, comprising specific connection structures and voltage application methods to detect copper ion migration, allowing for early identification of defects by measuring current values and determining the presence of short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If TSV structure is used to increase packaging density and reduce size, then packaging density is improved, but copper ion migration causes deterioration of electrical characteristics and reliability
Solution Approach 1:
The patent applies preliminary action by forming a test unit before packaging to detect copper ion migration early in the fabrication process. The test unit includes a test line extending from a pad toward the TSV, allowing detection of metal pollution before it reaches active regions and causes device failure. This early detection enables sorting of affected devices before packaging, preventing reliability issues in final products.
Solution Approach 2:
The patent uses an intermediary approach by introducing a test unit as a mediator between the TSV and active regions. The test unit includes a test line that acts as a sacrificial element, intentionally positioned to intercept migrated copper ions before they can reach and damage active device regions. This intermediary structure allows detection and prevention of reliability issues without compromising the TSV packaging density benefits.
2Ease of manufacture
If TSV is repetitively exposed to heat treatment during fabrication, then manufacturing process is completed, but copper ions diffuse or permeate into active region causing short-circuiting
Solution Approach 1:
The patent applies preliminary action by incorporating a test unit during fabrication that can detect copper ion migration before packaging. The test unit includes a test line that extends from a pad toward the TSV, allowing detection of metal pollution early in the fabrication process. This enables identification of devices with copper ion diffusion issues before they reach active regions and cause short-circuiting, allowing affected devices to be sorted out before final packaging.
3Reliability
If test unit is formed in KOZ adjacent to TSV, then copper ion migration can be detected early, but device area is increased
Solution Approach 1:
The patent applies local quality by concentrating the test unit functionality in a localized Keep-Out Zone (KOZ) adjacent to the TSV. The test line is formed only in this specific local region where copper ion migration is most likely to occur, rather than throughout the entire device. This localized approach enables early detection of copper ion migration while minimizing the additional area required, as the test structure is confined to a small region near the TSV where it is most needed.
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 solution enables the early detection of copper ion migration and subsequent defects, preventing the formation of bridges between metal contacts and transistors, thereby ensuring the semiconductor device's reliability and performance before packaging.
Implementation Method 1
measuring a current value flowing in the test unit; and determining a presence or an absence of short-circuiting in the test unit using the measured current value
Data Source
AI summary
A semiconductor device can detect a defective or faulty part caused by copper (Cu) ions migrated from a through silicon via (TSV), resulting in improvement of device characteristics and reliability. The semiconductor device includes: a semiconductor substrate including an active region defined by a device isolation region; a through silicon via (TSV) formed to pass through the semiconductor substrate; and a test unit formed in the vicinity of the TSV so as to determine the presence or absence of metal pollution caused by the TSV.