Protective Tape for Semiconductor Wafer Polishing
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Solution Overview
Problem
The existing method of applying protective tape to semiconductor wafers during polishing is challenging due to strong adhesion to photosensitive polyimide, making it difficult to peel off and potentially leaving glue on bump electrode surfaces, leading to conduction failures.
Innovation Solution
A semiconductor device manufacturing method involving the formation of specific openings in insulating and protective films to expose bonding pads and electrode layers, with a protective tape applied to cover external electrodes, utilizing a tape with a soft intermediate layer that adheres strongly to photosensitive polyimide but weakly to insulating films, facilitating easy removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protective tape is applied to cover bump electrodes during polishing, then wafer integrity is maintained, but the tape adheres strongly to photosensitive polyimide making it difficult to peel off and potentially leaving glue on electrode surfaces
Solution Approach 1:
The patent segments the protective film structure into multiple layers: a lower protective film layer that remains on the wafer and an upper peeling film layer that can be easily removed. This segmentation allows the protective function to be maintained while enabling easy removal of the tape without leaving residue on the electrodes.
Solution Approach 2:
The patent introduces a peeling film as an intermediary layer between the protective film and the external environment. This peeling film acts as a mediator that provides easy removal capability while the lower protective film maintains its protective function. The peeling film can be removed without adhering to the photosensitive polyimide, thus solving the tape removal difficulty.
2Reliability
If protective tape is applied to cover bump electrodes, then electrodes are protected during polishing, but glue residue may remain on electrode surfaces causing conduction failure
Solution Approach 1:
The protective structure is segmented into a lower protective film layer that stays on the wafer and an upper peeling film layer that is removed. This segmentation ensures that only the peeling film is removed, leaving the lower protective film intact on the electrodes, thus preventing glue residue while maintaining electrode protection.
Solution Approach 2:
The patent applies the peeling film over the protective film before the polishing process. This preliminary action of layering ensures that during removal, only the peeling film is taken off while the lower protective film remains in place, preventing any adhesive residue from contaminating the electrodes.
3Reliability
If photosensitive polyimide is used to form walls around wafer periphery to prevent water intrusion, then water protection is improved, but protective tape adhesion becomes too strong
Solution Approach 1:
The protective film is segmented into layers with different adhesion properties. The lower protective film layer has strong adhesion to the photosensitive polyimide for water protection, while the upper peeling film layer has weak adhesion for easy removal. This segmentation resolves the contradiction between strong adhesion for protection and weak adhesion for easy removal.
Solution Approach 2:
Different layers of the protective film have different local qualities: the lower layer is designed with strong adhesive properties to bond with the photosensitive polyimide wall for water protection, while the upper layer is designed with weak adhesive properties for easy peeling. This local differentiation of properties solves the adhesion strength contradiction.
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 method improves the yield of semiconductor device manufacturing by ensuring easy removal of the protective tape without leaving residue on the electrodes, preventing conduction failures and maintaining wafer integrity during polishing.
Implementation Method 1
utilizing a tape with a soft intermediate layer that adheres strongly to photosensitive polyimide but weakly to insulating films, facilitating easy removal
Data Source
AI summary
A semiconductor device manufacturing method improves the yield of manufacturing semiconductor devices. There are provided an insulating film for covering multiple bonding pads, a first protective film over the insulating film, and a second protective film over the first protective film. In semiconductor chips, multiple electrode layers are coupled electrically to each of the bonding pads via first openings formed in the insulating film and second openings formed in the first protective film. Multiple bump electrodes are coupled electrically to each of the electrode layers via third openings formed in the second protective film. In pseudo chips, the second openings are formed in the first protective film and the third openings are formed in the second protective film. The insulating film is exposed at the bottom of the second openings coinciding with the third openings. A protective tape is applied to a principal plane to cover the bump electrodes.