Laser Bonding Pressurizer Control for Thin Chip Warpage
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Solution Overview
Problem
Thinner semiconductor chips are prone to warpage when heated during laser bonding, leading to inadequate bonding between the chip and the substrate, which can result in operational failures.
Innovation Solution
A laser bonding system with a controller and apparatus that includes a stage for supporting the substrate and semiconductor chip, a pressurizer for applying pressure, temperature and pressure sensors for feedback control, and a laser radiation apparatus to bond the chip and substrate, allowing for precise temperature management and pressure adjustment to prevent warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser beam irradiation is used to bond semiconductor chip to substrate, then bonding efficiency is improved, but semiconductor chip warpage occurs due to heat
Solution Approach 1:
A transparent pressurizer is introduced as an intermediary component between the laser beam and the semiconductor chip. The pressurizer transmits the laser beam while applying pressure to the chip, preventing warpage during bonding. The pressurizer acts as a mediator that enables both laser transmission and mechanical constraint functions simultaneously.
Solution Approach 2:
The system dynamically adjusts the pressure applied by the pressurizer based on real-time temperature feedback from sensors. As the chip temperature changes during laser irradiation, the pressure parameter is modified to maintain optimal bonding conditions while preventing warpage, demonstrating parameter adaptation during the process.
2Manufacturing precision
If pressure is applied to prevent chip warpage, then bonding quality is improved, but system complexity increases
Solution Approach 1:
The pressurizer is designed to perform multiple functions: it applies pressure to prevent warpage, transmits the laser beam through its transparent material, and houses temperature sensors for monitoring. This multi-functionality reduces the need for separate components, thereby limiting the increase in system complexity while maintaining bonding quality.
Solution Approach 2:
Temperature sensors positioned within the pressurizer provide real-time feedback on chip temperature during bonding. This feedback enables automatic adjustment of pressure and laser parameters, improving bonding quality while using a relatively simple closed-loop control system rather than complex manual intervention mechanisms.
3Speed
If laser beam intensity is increased to improve bonding, then bonding speed is improved, but chip temperature control becomes difficult
Solution Approach 1:
Temperature sensors provide continuous feedback on chip temperature during laser bonding. This feedback enables the control system to adjust laser beam intensity in real-time, allowing high bonding speeds with intense laser radiation while preventing excessive temperature rise that would cause warpage or damage.
Solution Approach 2:
The bonding process uses periodic or pulsed laser irradiation rather than continuous high-intensity radiation. This periodic action allows brief intervals for heat dissipation and temperature equalization, maintaining high overall bonding speed while preventing excessive temperature accumulation in the chip.
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
The system ensures reliable bonding between the semiconductor chip and substrate by controlling temperature and pressure, preventing warpage and ensuring proper connection between the solder bump and pad, thus enhancing the operational integrity of the semiconductor package.
Implementation Method 1
a laser radiation apparatus configured to emit a laser beam through the pressurizer to bond a pad of the substrate and a connection terminal of the semiconductor chip
Implementation Method 2
a pressurizer configured to move up and down above the stage... to prevent warpage
Data Source
AI summary
A laser bonding system which improves bonding between a semiconductor chip and a substrate is provided. A laser bonding system comprises a laser bonding apparatus; and a controller configured to control the laser bonding apparatus, wherein the laser bonding apparatus includes a stage which supports a substrate including a pad, and a semiconductor chip including a connection terminal; a pressurizer which moves up and down above the stage; a temperature measuring sensor configured to measure a temperature of the semiconductor chip and generate a temperature value; and a laser radiation apparatus configured to bond a pad of the substrate and a connection terminal of the semiconductor chip, using a laser beam passing through the pressurizer, and the controller lifts the pressurizer in response to the temperature value.