Substrate Bonding Gas Control to Prevent Voids and Misalignment
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Solution Overview
Problem
The challenge during substrate bonding processes in semiconductor device manufacturing is the occurrence of voids due to vapor condensation and rapid pressure drops near the outer regions of bonded substrates, leading to reduced yield and alignment issues.
Innovation Solution
A substrate bonding apparatus and method that incorporates a process gas injector to supply a non-reactive gas between substrates and an air curtain generator to form an air curtain around the substrates, maintaining pressure and preventing vapor condensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrate bonding is performed without process gas injection and air curtain, then the bonding process is simple, but voids occur due to vapor condensation and pressure drops
Solution Approach 1:
A process gas (such as nitrogen or inert gas) is injected between the first and second substrates during bonding to act as an intermediary medium. This process gas prevents direct contact between vapor and substrate surfaces, eliminating vapor condensation that causes voids. The gas flows from the outer region toward the central portion, maintaining pressure equilibrium and preventing vacuum-induced void formation at the bonding interface.
Solution Approach 2:
An air curtain generated by injecting air around the substrates creates an inert atmospheric barrier. This air curtain isolates the bonding region from external vapor sources, preventing vapor from entering the bonding interface. The inert atmosphere maintained by the air curtain eliminates the root cause of vapor condensation and void formation, significantly improving bonding yield.
2Manufacturing precision
If process gas is injected between substrates, then void formation is suppressed, but the apparatus and process become more complex
Solution Approach 1:
The process gas serves as a mediator that maintains uniform pressure distribution between substrates during bonding. By flowing from the outer region toward the center, it prevents pressure drops that would cause misalignment and voids. The gas acts as a cushioning medium that ensures consistent contact pressure across the bonding interface, improving alignment precision.
3Reliability
If air curtain is generated around substrates, then vapor condensation is prevented, but energy consumption increases
Solution Approach 1:
The air curtain creates a localized inert atmosphere around the substrates using relatively low energy. By injecting air at the periphery, a stable air barrier forms that passively blocks vapor without requiring high energy input. The air curtain leverages natural air flow and pressure differential to maintain the inert environment, minimizing energy consumption while effectively preventing vapor condensation and void formation.
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 effectively suppresses void formation and improves bonding alignment by maintaining pressure and atmosphere stability during the substrate bonding process, enhancing yield and quality.
Implementation Method 1
supplying a process gas between the first substrate and the second substrate... a pressure may be prevented from rapidly dropping near the outer regions of the first and second substrates
Implementation Method 2
forming an air curtain by supplying an air curtain forming gas to surround the first substrate and the second substrate
Implementation Method 3
occurrence of a void may be suppressed because vapor is not condensed between the first and second substrates
Data Source
AI summary
A bonding method for bonding a first substrate to a second substrate includes fixing the first substrate to a first surface of a first bonding chuck and fixing the second substrate to a second surface of a second bonding chuck, the second surface facing the first surface; aligning the second bonding chuck above the first bonding chuck in a vertical direction or in a horizontal direction; bonding the first substrate to the second substrate to make a bonded substrate; and wherein, in the bonding the first substrate to the second substrate, injecting a process gas between the first substrate and the second substrate using a process gas injector surrounding at least one selected from the first bonding chuck and the second bonding chuck in a plan view and injecting an air curtain forming gas to form an air curtain surrounding the first substrate and the second substrate using an air curtain generator are performed in combination.