Laser Glass Bonding for High-Thermal-Conductivity Substrates
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Solution Overview
Problem
The bonding of highly thermal conductive substrates and glass substrates via laser sealing often results in rapid cooling of the sealing material, leading to cracks and bonding failure due to the rapid heat conduction from the highly thermal conductive substrate, which is exacerbated by the localized heating of laser sealing methods.
Innovation Solution
A method involving a two-step laser heating process where the sealing material is first preheated at a temperature below its softening point and then heated above it, reducing the risk of rapid cooling and cracking, with optional pre-treatment of the substrate with silicon oxide or nitride films to enhance wettability and thermal shock resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser sealing is used to bond highly thermal conductive substrate and glass substrate, then bonding efficiency is improved, but rapid cooling occurs causing cracks and bonding failure
Solution Approach 1:
The patent applies preliminary action by introducing a preheating step before the main laser sealing process. The sealing material is preheated to a temperature close to its softening point before actual bonding, which reduces the thermal shock and prevents rapid cooling-induced cracks. This preparatory heating action resolves the contradiction by maintaining both high bonding efficiency and reliability.
Solution Approach 2:
The patent implements periodic action through a two-stage laser heating process: first a preheating stage at lower power, then a main bonding stage at higher power. This periodic application of thermal energy allows the sealing material to gradually reach optimal bonding temperature without sudden thermal gradients, thereby preventing cracks while maintaining efficient bonding.
2Temperature
If highly thermal conductive substrate is used to prevent element deterioration, then heat dissipation is improved, but rapid heat conduction causes rapid cooling of sealing material
Solution Approach 1:
The preheating step serves as preliminary action that compensates for the high thermal conductivity of the substrate. By preheating the sealing material, the patent ensures that when the substrate conducts heat away, the sealing material remains above its softening point long enough to complete bonding, thus maintaining sealing layer integrity while preserving the substrate's heat dissipation capability.
Solution Approach 2:
The patent applies parameter changes by controlling the laser power and heating duration to achieve specific temperature profiles. The sealing material is heated to temperatures at or above its softening point, and the process parameters are optimized to account for the rapid heat conduction to the highly thermal conductive substrate, thereby maintaining sealing integrity.
3Use of energy by moving object
If localized heating is applied to seal the bonding area, then energy efficiency is improved, but thermal gradient increases causing cracks
Solution Approach 1:
The preheating step acts as preliminary action that reduces the thermal gradient before main bonding. By initially heating the sealing material at lower power over a slightly larger area, the patent minimizes sudden thermal shocks while maintaining energy efficiency through localized heating during the subsequent bonding stage.
Solution Approach 2:
The two-stage laser heating process implements periodic action where the first period uses lower power to reduce thermal gradients, and the second period uses higher power for efficient localized bonding. This periodic approach maintains energy efficiency while preventing thermal shock-induced cracks.
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 significantly reduces the occurrence of bonding failure between the highly thermal conductive substrate and the glass substrate, enhancing the hermeticity and heat dissipation properties of the bonded body.
Implementation Method 1
a bonding step of forming the sealing layer by irradiating the sealing material with laser light
Implementation Method 2
the sealing material and the glass substrate having been heated may be rapidly cooled due to the rapid progress of heat conduction from the sealing material to the highly thermal conductive substrate
Implementation Method 3
The sealing material softens and flows by heating with laser light, and the base substrate (container) and the glass substrate (glass cover) adhere to each other
Data Source
AI summary
A method of manufacturing a bonded body includes a preparation step of interposing a sealing material containing glass between a highly thermal conductive substrate and a glass substrate, and a bonding step of forming a sealing layer by irradiating the sealing material with laser light. The bonding step includes a first heating step of preheating the sealing material at a temperature lower than a softening point of the sealing material or a temperature at which the sealing material is prevented from softening and flowing by irradiation with the laser light, and a second heating step of heating, after the first heating step, the sealing material at a temperature equal to or higher than the softening point of the sealing material or a temperature at which the sealing material softens and flows by irradiation with the laser light.