Notched Central Pad Layout for Large-Die Wire Bonding
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Solution Overview
Problem
Current semiconductor manufacturing methods face challenges in supporting large dies during the wire bonding process, leading to issues such as non-stick on pads, non-optimum welding, and yield loss due to inadequate die support, especially when bond pad positions are not fully supported by metal areas.
Innovation Solution
A semiconductor device design featuring a central pad with notches to accommodate long lead terminals and a non-conductive adhesive layer, ensuring the die is securely positioned and electrically connected, with the mold enclosing the die, wires, and lead terminals to form an outer surface, providing enhanced support and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the die surface area is increased to accommodate more terminals, then the electrical connectivity is improved, but the die support during wire bonding deteriorates leading to damage risk
Solution Approach 1:
The central pad is segmented by introducing notches that divide it into multiple regions. These notches create separate support zones for the die, allowing the die to be securely held during wire bonding while accommodating a larger die surface area with more terminals. The segmentation transforms a single large unsupported area into multiple smaller supported regions.
Solution Approach 2:
The solution extends the support structure vertically by using long lead terminals that protrude through the mold compound. This vertical extension provides additional support points beneath the die, compensating for the reduced horizontal support area caused by the larger die size relative to the central pad.
2Area of moving object
If the die size is made larger than the central pad area, then more die terminals can be positioned, but the die becomes insufficiently supported during manufacturing
Solution Approach 1:
The notches are pre-formed in the central pad structure before die mounting. This preliminary structuring creates predetermined support zones that guide proper die placement and ensure adequate support during subsequent wire bonding operations, eliminating the need for additional support structures.
Solution Approach 2:
The long lead terminals act as intermediary support elements between the central pad and the die. These lead terminals extend through the mold compound to provide mechanical support and positioning for the die, mediating the support function when the central pad area alone is insufficient.
3Ease of operation
If bond pads are positioned near the die edge for easy assembly, then assembly ease is improved, but the metal support area becomes insufficient
Solution Approach 1:
The notches create local variations in the central pad structure, concentrating metal support material in specific regions beneath the die. This local quality enhancement provides focused support areas at critical locations (near die edges where bond pads are positioned) without requiring an overall increase in central pad size.
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 design minimizes the risk of die damage by ensuring proper support and secure electrical connections, improving bonding forces and reliability in the wire bonding process for large dies.
Implementation Method 1
a non-conductive adhesive layer, wherein the die is placed on the non-conductive adhesive layer
Data Source
Figure 1A~1B
Figure 2A
Figure 2B~2C
AI summary
The present disclosure proposes a semiconductor device and a method of manufacturing thereof, the semiconductor device comprising a die having a first side and a second side, wherein the die comprises, on a perimeter of the second side, a plurality of die terminals, a central pad having an inner side and an outer side, wherein the central pad comprises an at least one notch, a mold, an non-conductive adhesive layer, wires, at least two lead terminals having an inner side and an outer side, wherein the at least one lead terminal is configured as a long lead terminal. Each of the long lead terminals is placed in the notch. The non-conductive adhesive layer is placed on at least part of the inner side of the central pad and on at least part of the inner side of each of the long lead terminals.