Wedge Bonding Tool Marks for Non-Destructive Reliability Inspection
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Solution Overview
Problem
Current methods for evaluating bonding reliability in wedge bonding, such as peel and shear tests, are destructive and cannot inspect all bonding positions due to obstructions like wiring and resin cases, and rely heavily on inspector proficiency, leading to inaccurate non-destructive inspections.
Innovation Solution
A wedge tool with a groove and convex portions on its tip, where the bonding wire contacts the convex portions during deformation, forming a transfer mark that indicates bonding reliability, allowing for non-destructive and accurate quality determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-destructive inspection methods such as measuring microscopes, video analysis, or laser displacement meters are used to measure bonding wire deformation, then bonding reliability can be inspected without destroying the device, but inspection accuracy deteriorates when imaging is blocked by wiring, resin cases, or external electrodes
Solution Approach 1:
The wedge tool tip is segmented into multiple functional regions: a groove for wire positioning and multiple convex portions at different positions. Each convex portion creates a transfer mark that provides inspection information, allowing the inspection function to be distributed across multiple contact points rather than relying on a single measurement location.
Solution Approach 2:
A transfer mark is introduced as an intermediary indicator between the bonding process and the inspection process. The convex portions on the wedge tool transfer marks onto the bonding wire during bonding, and these marks serve as visible indicators that mediate the assessment of bonding quality without requiring direct measurement of the bonding interface itself.
2Reliability
If sensitive virtual inspection by comparing limit samples and inspection objects is used, then non-destructive inspection can be performed, but inspection accuracy deteriorates due to dependence on inspector sense and proficiency
Solution Approach 1:
The bonding process itself serves the inspection function by automatically creating transfer marks on the bonding wire through the convex portions of the wedge tool. The bonding wire deforms and contacts the convex portions during bonding, self-generating inspection indicators without requiring separate inspection operations or human judgment.
Solution Approach 2:
The transfer marks created by the convex portions provide visual indicators on the bonding wire that can be detected and measured. These marks create observable changes in the bonding wire geometry that serve as quantitative indicators of bonding quality, replacing subjective visual inspection with objective mark detection.
3Measurement precision
If all bonding positions are inspected using measurement apparatus, then complete quality assessment can be achieved, but inspection becomes impossible when imaging is prevented by device structures
Solution Approach 1:
The inspection information is extracted from the bonding process itself through the creation of transfer marks. Instead of requiring access to the bonding interface for direct measurement, the method extracts quality information in the form of marks on the bonding wire that can be observed from outside the device structure, bypassing imaging blockage issues.
Solution Approach 2:
The inspection approach shifts from directly measuring the bonding interface in three-dimensional space to observing transfer marks on the bonding wire surface. This dimensional shift allows inspection of bonding quality through marks that are accessible on the wire exterior, avoiding the need to image through or around obstructive device structures.
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
The transfer mark provides a reliable and accurate means to assess bonding quality non-destructively, even in complex semiconductor device configurations, ensuring the reliability of the bonding process without damaging the device.
Implementation Method 1
an ultrasonic vibration is applied to the bonding wire supplied to a lower side of the wedge tool through the wire guide while pressing the bonding wire on a bonded object with the wedge tool body part
Implementation Method 2
the bonding wire comes in contact with the convex portion by a deformation of the bonding wire in a bonding part of the bonding wire and a bonded object bonded to each other by a wedge bonding
Data Source
AI summary
It is an object to enable a non-destructive inspection of reliability of a bonding part and enabling an accurate inspection. A wedge tool includes: a groove which is formed along a direction of an ultrasonic vibration in a tip portion and in which a bonding wire is disposed in a wedge bonding; a first planar surface and a second planar surface disposed on both sides of the groove; and at least one convex portion formed away from the groove in at least one of the first planar surface and the second planar surface, wherein the bonding wire comes in contact with the convex portion by a deformation of the bonding wire in a bonding part of the bonding wire and a bonded object bonded to each other by a wedge bonding.