Wire Bonding Pressing Portion for Stacked Semiconductor Reliability
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Solution Overview
Problem
Conventional wire bonding methods for stacked semiconductor devices require a large number of steps, leading to increased time and cost, and cause damage to semiconductor dies, especially when forming bumps on multiple layers.
Innovation Solution
A semiconductor device and wire bonding method that connects two out of three or more bonding points with a wire using a pressing portion formed by bonding an initial ball and crushing the ball neck, with a first wire extending to a second bonding point and a second wire looped and joined to the pressing portion from a third bonding point, reducing the number of bonding steps and minimizing die damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bumps are formed on pads of multiple semiconductor dies before wire bonding, then connection reliability is improved, but the number of bonding steps increases and processing time extends
Solution Approach 1:
The invention extracts the bump formation step from the bonding process by using a pre-formed ball at the wire tip as the bonding element, eliminating the need to form separate bumps on each pad before bonding. This reduces the number of steps while maintaining reliable connections.
Solution Approach 2:
The ball is pre-formed at the wire tip before the bonding process begins. This preliminary preparation of the bonding element eliminates the need for subsequent bump formation steps on the semiconductor die pads, reducing overall processing time while ensuring reliable bonding.
2Reliability
If multiple bonding steps are performed to connect wires between semiconductor dies, then connection reliability is improved, but the complexity of the bonding process increases
Solution Approach 1:
The invention merges the ball formation and bonding operations into a single step by using a pre-formed ball at the wire tip. This consolidation reduces the number of separate bonding steps required to connect wires between semiconductor dies, simplifying the overall process while maintaining connection reliability.
Solution Approach 2:
The pre-formed ball at the wire tip serves multiple functions: it acts as the bonding element for initial attachment, provides a controlled bonding interface, and eliminates the need for separate bump formation processes. This multi-functionality reduces process complexity while ensuring reliable connections.
3Reliability
If conventional wire bonding methods are used to connect multiple bonding points, then all bonding points are connected, but the number of bonding operations increases and die damage risk increases
Solution Approach 1:
The invention extracts the ball formation step from the bonding process by using a pre-formed ball at the wire tip, eliminating the need for repeated ball formation or bump creation operations on the semiconductor die pads. This reduction in operational steps directly decreases the risk of die damage while maintaining complete connection of all bonding points.
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 method reduces the number of bonding steps and time while minimizing damage to semiconductor dies by effectively connecting wires with a smaller number of bonding operations and compressing the second wire between capillary components, enhancing the semiconductor device's efficiency and reducing defects.
Implementation Method 1
crushing a ball neck formed by the bonding, and pressing a side surface of the wire folded back onto the crushed ball neck
Data Source
AI summary
A semiconductor device has a first layer pressing portion that is formed by crushing a ball neck formed by bonding an initial ball onto a first layer pad of a first layer semiconductor die and pressing the side of a wire folded onto the crushed ball neck, a first wire extended in the direction of a lead from the first layer pressing portion, and a second wire that is looped from a second layer pad of a second layer semiconductor die toward the first layer pressing portion and joined onto the second layer pad side of the first layer pressing portion. Thereby, the connection of wires is performed at a small number of times of bonding, while reducing damages caused on the semiconductor dies.