Vacuum Laser Reflow Compression for Void-Free Multi-Chip Bonding
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Solution Overview
Problem
Conventional laser reflow processes face challenges in efficiently bonding multiple semiconductor chips simultaneously due to difficulties in achieving a homogenized laser beam and uniform thermal energy distribution, leading to increased defect rates and void formation during soldering.
Innovation Solution
A compression-type laser reflow apparatus with a vacuum chamber that uses a light-transmitting pressing member to simultaneously press and reflow multiple electronic components while irradiating a laser beam, preventing void formation by maintaining a vacuum atmosphere and utilizing overlapping laser modules for improved energy distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional laser reflow process is used to bond multiple semiconductor chips simultaneously, then productivity is improved, but manufacturing precision deteriorates due to inability to achieve homogenized laser beam and uniform thermal energy distribution
Solution Approach 1:
The patent divides the laser beam into multiple segments using beam splitting optics, with each segment directed to a specific chip position. This segmentation allows independent control of laser parameters for each chip, achieving uniform thermal energy distribution across multiple chips simultaneously bonded, thus resolving the contradiction between mass processing capability and bonding uniformity.
2Ease of operation
If conventional laser reflow process is used in air atmosphere, then ease of operation is improved, but reliability deteriorates due to void formation and oxidation during soldering
Solution Approach 1:
The patent implements a vacuum chamber environment for the laser reflow process, removing oxygen and other reactive gases that cause oxidation and void formation during soldering. This inert environment maintains high reliability of solder joints while the automated vacuum system keeps operational complexity manageable, resolving the contradiction between ease of operation and reliability.
3Ease of operation
If thermal reflow oven technology is used for bonding ultra-thin semiconductor chips, then ease of operation is improved, but manufacturing precision deteriorates due to warpage and bonding adhesion failures caused by CTE difference
Solution Approach 1:
The patent replaces the conventional thermal reflow oven with a laser-based heating system that delivers energy directly to the solder joints. This substitution allows precise localized heating that minimizes thermal stress and warpage in ultra-thin chips, while maintaining operational simplicity through automated laser control, thus resolving the contradiction between ease of operation and bonding adhesion quality.
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 enhances productivity by allowing mass processing with reduced defect rates and improved reliability by preventing voids and oxidation, thereby improving the overall quality of the laser reflow process.
Implementation Method 1
bonding an electronic component to a substrate by irradiating a laser beam into the vacuum chamber through the light-transmitting pressing member
Implementation Method 2
pressing with a light-transmitting pressing member and irradiating a laser beam
Implementation Method 3
pressing the plurality of electronic components arranged on the substrate by the pressing unit with a light-transmitting pressing member in a vacuum atmosphere inside the vacuum chamber
Data Source
Figure 1
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AI summary
A compression-type laser reflow apparatus with a vacuum chamber comprising: a vacuum chamber formed of a closed space of a hexahedron, each having an inlet and outlet selectively opened and closed for drawing in and withdrawing the substrate into and out of the sealed space on one side and the other side of the hexahedron, and in which a laser beam irradiation hole is formed in an upper portion of the sealed space; a holder unit provided above the laser beam irradiation hole of the vacuum chamber so that the light-transmitting pressing member is inserted and mounted in a replaceable manner, and maintains an airtight state with the laser beam irradiation hole of the vacuum chamber not to destroy the vacuum atmosphere inside the vacuum chamber; a pressing unit that selectively presses the substrate positioned inside the vacuum chamber using the light-transmitting pressing member as the holder unit on which the light-transmitting pressing member is mounted is raised and lowered in the vertical direction; wherein pressing the plurality of electronic components arranged on the substrate by the pressing unit with a light-transmitting pressing member in a vacuum atmosphere inside the vacuum chamber, and at the same time, bonding an electronic component to a substrate by irradiating a laser beam into the vacuum chamber through the light-transmitting pressing member.