Bonding Apparatus Ring Members Prevent Void Formation
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Solution Overview
Problem
The existing bonding apparatus for semiconductor substrates often results in poor bonding due to voids generated at the outer edge portions, caused by adiabatic expansion of gas between the substrates, leading to reduced reliability.
Innovation Solution
The bonding apparatus incorporates ring members on the outer edges of the substrates, which thermally expand to facilitate even bonding from the center to the edges, reducing the speed of adiabatic expansion and preventing gas condensation, thereby eliminating voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the upper substrate is bonded to the lower substrate from center to outer circumferential portion, then the bonding area is expanded and bonding is achieved, but gas between the outer edge portions makes abrupt transition from high-pressure to low-pressure state causing adiabatic expansion and moisture condensation, leading to void formation and poor bonding
Solution Approach 1:
A groove is formed at the outer circumferential portion of the upper substrate, acting as an intermediary structure that controls gas discharge during bonding. This groove mediates the pressure transition by providing a controlled path for gas escape, preventing abrupt pressure changes and the resulting adiabatic expansion that causes voids and bonding defects.
Solution Approach 2:
The bonding process is segmented into controlled stages by introducing the groove structure at the outer circumferential portion. This segmentation allows the bonding to proceed from center to edge in a controlled manner, with the groove facilitating staged gas discharge and pressure equalization, preventing the simultaneous abrupt pressure transition that occurs in conventional bonding.
2Productivity
If bonding is performed from center to outer circumferential portion, then bonding area expands, but voids are generated at outer edge portions due to adiabatic expansion
Solution Approach 1:
The groove structure serves as an intermediary that enables continuous bonding area expansion while controlling the gas discharge process. By providing a dedicated gas escape path at the outer circumferential portion, the groove allows the bonding front to advance to the edges without generating voids, thus maintaining manufacturing precision during productivity improvement.
Solution Approach 2:
The groove is preliminarily formed at the outer circumferential portion before bonding begins. This preliminary action prepares a controlled gas discharge path in advance, ensuring that when the bonding front reaches the outer edges, gas can escape smoothly without causing adiabatic expansion and void formation, thereby maintaining bonding quality during area expansion.
3Productivity
If gas makes abrupt pressure transition during bonding, then bonding process is completed, but moisture condensation occurs due to adiabatic expansion
Solution Approach 1:
The groove acts as an intermediary structure that moderates the pressure transition of gas during bonding. By providing a controlled discharge path, it prevents the abrupt pressure drop that causes adiabatic expansion and moisture condensation, thereby maintaining bonding reliability while allowing the bonding process to complete efficiently.
Solution Approach 2:
The groove structure changes the pressure parameters of the gas during bonding by providing a controlled discharge path. This modifies the pressure transition from abrupt to gradual, preventing adiabatic expansion and moisture condensation, thus improving bonding reliability without compromising process completion.
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 solution ensures reliable bonding by moderating the pressure difference and preventing gas condensation between the substrates, enhancing the bonding process and reducing void formation.
Implementation Method 1
ring members on the outer edges of the substrates, which thermally expand to facilitate even bonding from the center to the edges
Implementation Method 2
gas between the outer edge portion of the upper substrate and an outer edge portion of the lower substrate makes an abrupt transition from a high-pressure state to a low-pressure state and makes adiabatic expansion
Implementation Method 3
When moisture contained in the gas is condensed because of adiabatic expansion of the gas
Data Source
AI summary
A bonding apparatus according to the present embodiment includes a first holder and a second holder. The first holder holds a first substrate. The second holder sucks a second substrate, opposes the second substrate to the first substrate, and bonds the second substrate to the first substrate. A first ring stage is provided on an outer circumference of the first holder and allows a first ring member provided on an outer edge of the first substrate to be mounted thereon. A second ring stage is provided on an outer circumference of the second holder and allows a second ring member provided on an outer edge of the second substrate to be mounted thereon. A first heater is provided in the first ring stage. A second heater is provided in the second ring stage.