Semiconductor Bond Wire with Soft Intermediate Element
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Solution Overview
Problem
The high cost and mechanical damage issues associated with gold bond conductors in semiconductor arrangements, as well as the oxidation problems with copper and silver bond conductors, necessitate a more cost-effective and gentle connection method for integrated circuits.
Innovation Solution
A semiconductor arrangement using bond conductors made of materials like copper or copper alloys, with a wedge-shaped end indirectly connected to a softer electrically conductive intermediate element, such as gold or gold alloys, to reduce mechanical loading on integrated circuits and prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold bond conductors are used, then reliability and resistance to tarnishing are improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent uses a composite bond conductor structure consisting of a copper core surrounded by a gold alloy coating. This composite structure combines the low cost and good electrical conductivity of copper with the tarnish resistance of gold alloy, achieving a balance between manufacturing cost and reliability. The gold alloy coating layer thickness is controlled at 0.5-5 micrometers to provide adequate protection while minimizing material cost.
Solution Approach 2:
The patent applies gold alloy coating only on the surface of the copper bond conductor, particularly at the bonding ends, rather than using pure gold throughout. This local application of gold provides tarnish resistance at critical contact points while keeping the bulk material cost-effective copper, resolving the contradiction between reliability and manufacturing cost.
2Ease of manufacture
If copper or silver bond conductors are used, then manufacturing cost is reduced, but oxidation and tarnishing occur reducing bonding capacity
Solution Approach 1:
The patent employs a copper core with gold alloy coating composite structure. The copper core provides low manufacturing cost and good electrical conductivity, while the gold alloy coating layer (0.5-5 micrometers thick) prevents oxidation and tarnishing, maintaining bonding capacity throughout the product lifecycle.
Solution Approach 2:
The patent creates a protective environment by coating the reactive copper surface with inert gold alloy material. This coating acts as a barrier that prevents direct contact between oxygen and the copper core, effectively creating an inert protective environment that eliminates oxidation issues while maintaining the cost advantages of copper.
3Reliability
If bond conductors are pressed directly onto contact pads, then electrical connection is established, but mechanical stress damages the integrated circuit
Solution Approach 1:
The patent introduces a spherical intermediate element made of soft material (gold, silver, or copper alloy) as a mediator between the bond conductor and the contact pad. This intermediate element receives the bonding force and distributes it over a larger area, preventing stress concentration and damage to the integrated circuit while ensuring reliable electrical connection.
Solution Approach 2:
The soft intermediate element is placed on the contact pad before the bond conductor is attached. This intermediate element acts as a cushion that absorbs and distributes the mechanical stress during the bonding process, preventing damage to the integrated circuit before the actual electrical connection is established.
4Object-affected harmful factors
If spherical intermediate elements are used to reduce compressive loading, then mechanical stress on integrated circuit is reduced, but device complexity increases
Solution Approach 1:
The patent uses a simple spherical intermediate element made of soft material as an intermediary between the bond conductor and contact pad. This simple geometric shape with soft material properties effectively reduces compressive loading through stress distribution without introducing complex mechanisms or structures.
Solution Approach 2:
The patent reduces mechanical stress by changing the material parameter (softness) of the intermediate element rather than changing the structural complexity. The soft material property allows the intermediate element to deform and distribute stress, achieving stress reduction through material selection rather than structural design.
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 reduces manufacturing costs and complexity while minimizing mechanical stress on integrated circuits, allowing for a more efficient and cost-effective connection method compared to traditional gold bond conductors.
Implementation Method 1
The bond conductors may be coupled to the pad and the contact using either thermosonic bonding or ultrasonic bonding.
Implementation Method 2
The bond conductors may be coupled to the pad and the contact using either thermosonic bonding or ultrasonic bonding.
Implementation Method 3
the ball-wedge technique exerts compressive loading (e.g., using ultrasonic techniques) on the second integrated circuit when the bond wire is flattened and pressed thereon
Data Source
AI summary
A semiconductor arrangement includes first and second integrated circuits (dies), an electrically conductive intermediate element, and one or more bond conductors. The first and the second integrated circuits are arranged in a package. The first integrated circuit has a first contact pad. The second integrated circuit has a second contact pad. The intermediate element is disposed on the second contact pad. The conductors electrically connect the first and the second integrated circuits. At least one of the bond conductors has a first end electrically connected to the first contact pad, and a second wedge shaped end electrically connected to the intermediate element. The bond conductor is made of a first material and the intermediate element is made of a second material which is softer than the first material.