Wiring Board Auxiliary Bump Electrode Alignment
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Solution Overview
Problem
Conventional registration methods for semiconductor chips on tape carrier substrates face accuracy issues due to errors in positional alignment between electrode pads and bump electrodes, particularly as the pitch between conductor wirings and bump electrodes decreases, leading to insufficient connection reliability.
Innovation Solution
A wiring board with auxiliary conductor wirings and auxiliary bump electrodes is introduced, allowing for precise positioning of semiconductor chips by referencing the auxiliary bump electrodes, which are formed similarly to the main bump electrodes and integrated into the solder resist layer for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If register marks are formed separately from bump electrodes in different process steps, then the manufacturing process is simpler, but the positional alignment accuracy between electrode pads and bump electrodes deteriorates
Solution Approach 1:
The patent merges the formation of register marks and bump electrodes into a single integrated structure. The register marks are formed as conductive patterns on the same insulating film base as the bump electrodes, and both are created in the same manufacturing process steps. This integration ensures that the register marks and bump electrodes have identical positional relationships, eliminating alignment errors that would occur if they were formed separately.
Solution Approach 2:
The conductive patterns serve multiple functions: they act as both register marks for positioning and as functional conductor wirings for electrical connections. By making the register marks and bump electrodes structurally identical and formed simultaneously, the system achieves both positioning accuracy and electrical functionality without requiring separate manufacturing processes.
2Quantity of substance
If the pitch between conductor wirings is decreased to increase integration density, then the quantity of components increases, but the difficulty of detecting and measuring positional alignment increases
Solution Approach 1:
The patent creates exact copies of the bump electrode structures as register marks. Since the register marks are formed using the same conductive patterns and manufacturing processes as the bump electrodes, they are perfect replicas in terms of positional relationship. This copying approach allows for easy detection and measurement of alignment using the same imaging and measurement techniques applied to the functional bump electrodes, regardless of pitch reduction.
Data Source
AI summary
A flexible insulating base, a plurality of conductor wirings aligned on the flexible insulating base, and bump electrodes provided respectively in end portions of the plurality of conductor wirings in a region where a semiconductor chip is to be placed are provided. The semiconductor chip is mounted on the conductor wirings by bonding electrode pads formed on the semiconductor chip to the bump electrodes. An auxiliary conductor wiring formed similarly to the conductor wirings is provided on the insulating base, and an auxiliary bump electrode formed similarly to the bump electrodes is provided on the auxiliary conductor wiring, so that the electrode pads formed on the semiconductor chip can be registered with respect to the bump electrodes on the conductor wirings by positioning the semiconductor chip with reference to the auxiliary bump electrode. It is possible to configure a wiring board having register marks capable of positioning electrode pads of a semiconductor chip with respect to bump electrodes with high accuracy.