Semiconductor Chip Bump Electrode Segmentation for Wiring Density
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Solution Overview
Problem
The challenge in reducing the size of semiconductor chips used in LCD drivers while maintaining efficient interconnection wiring layout and adhesive force, as conventional designs restrict the layout arrangement due to the fixed positions of bump electrodes and the need for larger pads to match the bump electrodes.
Innovation Solution
The design involves forming a semiconductor chip with pads smaller than the bump electrodes, allowing for additional wiring layers beneath the bump electrodes, and structuring bump electrodes with a combination of narrow and wider portions to optimize layout flexibility and adhesive area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bump electrodes are enlarged to increase adhesive force between semiconductor chip and glass substrate, then adhesive force is improved, but pad area must be enlarged to match bump electrodes, which increases chip size
Solution Approach 1:
The bump electrode is segmented into two functional portions: a bonding pad portion that contacts the glass substrate for adhesive force, and a terminal electrode portion that provides electrical connection. This segmentation allows the bonding pad portion to be enlarged for strength while the terminal electrode portion can be optimized for electrical function, and the insulating film with opening allows wiring to pass through beneath the bump electrode, reducing the need for enlarged pads.
Solution Approach 2:
The invention utilizes the vertical dimension by forming wiring layers beneath the bump electrode that pass through an opening in the insulating film. This allows interconnection wires to route under the bump electrode structure rather than requiring larger horizontal pad areas, thus enabling the bump electrode to be enlarged for adhesive force without proportionally increasing chip size.
2Strength
If pad area is enlarged to match bump electrode area, then adhesive force is improved, but space for interconnection wiring is reduced, requiring larger chip size
Solution Approach 1:
The bump electrode is divided into a bonding pad portion and a terminal electrode portion, with the insulating film containing an opening that allows wiring to pass through. This segmentation enables the bonding pad portion to be enlarged for adhesive force while the wiring can route through the opening beneath the bump electrode, maintaining wiring layout flexibility without requiring enlarged pads.
Solution Approach 2:
The insulating film with an opening acts as an intermediary structure that allows interconnection wires to pass through beneath the bump electrode. This mediator enables wiring to route under the enlarged bump electrode without requiring the pad area to match the bump electrode area, thus maintaining both adhesive force and wiring layout flexibility.
3Strength
If bump electrode position is fixed directly above bonding pads, then adhesive force is improved, but layout arrangement of interconnection wires is restricted
Solution Approach 1:
The bump electrode is segmented into a bonding pad portion that maintains direct contact with the glass substrate for adhesive force, and a terminal electrode portion that can be positioned independently. The insulating film with opening allows wiring to pass through, enabling the terminal electrode portion to be positioned to optimize electrical connections without being constrained by the bonding pad position, thus improving layout arrangement flexibility.
Solution Approach 2:
The invention utilizes the vertical dimension by allowing wiring to pass through the insulating film opening beneath the bump electrode. This enables the bump electrode to be positioned for optimal adhesive force while interconnection wires can route through the opening from different lateral positions, providing greater layout arrangement flexibility without compromising adhesive strength.
Data Source
AI summary
A semiconductor device manufacturing technique which allows reduction of semiconductor chip size. First, a pad and other wires are formed over an insulating film. A surface protective film is formed over the insulating film including the pad and wires, and an opening is made in the surface protective film. The opening lies over the pad and exposes a surface of the pad. A bump electrode is formed over the surface protective film including the opening. Here, the pad is smaller than the bump electrode. Consequently, the wires are arranged just beneath the bump electrode in the same layer as the pad 10. In other words, the wires are arranged in space which becomes available because the pad is small enough.