Ball Bond Channel Structure for Stable Semiconductor Wire Bonding
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Solution Overview
Problem
Existing wire bonding techniques face inefficiencies in energy transfer and throughput due to suboptimal capillary tools, leading to issues such as ball bonds lifting off bond pads during the bonding process.
Innovation Solution
The use of a capillary tool with a boss protruding from its distal end to form a channel in the proximal surface of the ball bond, enhancing energy transfer and improving bonding efficiency by allowing lower force application during the bonding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional capillary tools are used for ball bonding, then the bonding process can be completed, but energy transfer is inefficient and ball bonds may lift off bond pads
Solution Approach 1:
The capillary tool features a boss structure at its distal end that creates a localized channel in the proximal surface of the ball bond. This local structural modification concentrates energy transfer at the critical interface between the ball bond and bond pad, improving energy efficiency while preventing ball bond lift-off through enhanced localized bonding pressure.
2Reliability
If higher force is applied during bonding to prevent lift-off, then ball bond stability improves, but throughput decreases due to slower bonding cycles
Solution Approach 1:
The boss structure modifies the bonding interface geometry, creating a channel that allows for optimized force distribution. This structural parameter change enables effective bonding at lower applied forces, thereby maintaining ball bond stability while reducing bonding cycle time and increasing overall throughput.
3Manufacturing precision
If traditional capillary tools without boss are used, then device complexity is lower, but manufacturing precision of ball bond channel is insufficient
Solution Approach 1:
The boss structure is pre-formed on the capillary tool before the bonding process. This preliminary structural feature automatically creates the desired channel in the ball bond proximal surface during the bonding operation, ensuring precise channel formation without requiring additional manufacturing steps or complex tooling modifications.
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 improves energy transfer and increases throughput by reducing the likelihood of ball bonds lifting off bond pads, resulting in more reliable and efficient wire bonding.
Implementation Method 1
vibrating the capillary tool ultrasonically while the distal end tip, including the boss, engages a proximal surface of the ball
Data Source
AI summary
A semiconductor device includes a semiconductor die having a die surface, in which the die surface includes a bond pad. A ball bond has a distal surface and flattened-disk shape extending from the distal surface and terminating in a proximal surface spaced apart from the distal surface. The distal surface is coupled to the bond pad and a channel extends a depth into the proximal surface surrounding a central portion of the proximal surface. A bond wire extending from the central portion of the proximal surface, in which the channel is spaced apart from and surrounds the bond wire.