Anode Bonding Electrode Extension for Silicon-Glass Substrates
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Solution Overview
Problem
Anode bonding between silicon and glass substrates is challenging due to conductivity differences and electrode placement issues, leading to voltage drops and positional deviations during the bonding process, especially when electrodes cannot be provided on the glass substrate surface or when the bonding surface is large.
Innovation Solution
The method involves creating through holes in the silicon substrate to allow cathode electrodes to contact the glass substrate, enabling direct current voltage application between anode and cathode electrodes, with the cathode electrodes positioned within 20 mm of the bonding region, and using a combination of metal and glass sections for the cathode electrodes to facilitate effective bonding without requiring additional supporting members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the glass substrate is made larger than the silicon substrate and the electrode is provided to the peripheral part of the glass substrate, then the anode bonding can be conducted, but a large voltage drop occurs on the bonding surface distant from the electrode due to the low conductivity of the glass substrate
Solution Approach 1:
The electrode is extended from the peripheral part of the glass substrate onto the silicon substrate in the lateral dimension. This dimensional extension allows the electrode to reach the bonding surface directly, eliminating the voltage drop problem that occurs when the electrode is restricted to the glass substrate periphery.
2Reliability
If pressing force is applied to the peripheral part of the glass substrate to ensure electrode contact, then sufficient contact is achieved, but uplift occurs on the bonding surface or positional deviations occur between laminated substrates
Solution Approach 1:
The electrode is positioned to extend onto the silicon substrate in the lateral direction, allowing contact force to be applied directly at the bonding surface location rather than at the peripheral part. This eliminates the lever arm effect that causes uplift and positional deviation when pressing force is applied to the periphery.
3Device complexity
If the electrode is provided to the outer peripheral part of the glass substrate, then the structure is simplified, but anode bonding becomes difficult when the bonding surface is large due to excessive voltage drop
Solution Approach 1:
The electrode structure is extended laterally onto the silicon substrate, transforming from a peripheral-only configuration to a configuration that reaches the bonding surface. This maintains structural simplicity while eliminating the voltage drop issue that plagues large bonding surfaces with peripheral electrodes.
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 approach allows for successful anode bonding without positional deviations, even when electrodes cannot be placed on the glass substrate surface, by ensuring effective electrostatic force distribution and preventing voltage drops, thus enabling the production of liquid droplet discharging heads with improved bonding quality.
Implementation Method 1
applying a direct current voltage between the anode electrode and the cathode electrode on the condition that the glass substrate and the silicon substrate are heated
Implementation Method 2
on the condition that the glass substrate and the silicon substrate are heated
Data Source
AI summary
Provided is an anode bonding method by which a silicon substrate and a glass substrate are well anodically bonded without generating positional shift, even when an electrode cannot be arranged on a surface on the opposite side to a bonding surface of a glass substrate and the bonding surface is large. The method for anodically bonding the glass substrate and the silicon substrate is provided with a step of placing on the glass substrate the silicon substrate whereupon a through hole is arranged; a step of bringing the anode electrode into contact with the surface of the overlapped silicon substrate opposite to the surface facing the glass substrate, and bringing an cathode electrode into contact with the glass substrate through the through hole arranged on the silicon substrate; and a step of applying a direct current voltage to the anode electrode and the cathode electrode in a state where the glass substrate and the silicon substrate are heated.