Bonder Force Calibration Using Automated Load Cell Mapping
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Solution Overview
Problem
Current calibration methods for bonders are inaccurate and time-consuming, especially when dealing with non-linear force actuators and limited space for external measuring devices, leading to fluctuations and errors in bonding force control.
Innovation Solution
A fully automatic or semi-automatic calibration method using a load cell and sensors to record bonding force, deflection, and current values without manual intervention, allowing for precise mapping of force actuator characteristics and enabling permanent installation of the measuring device outside the bonding area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual calibration method with optical display and input devices is used, then operator can enter force values, but significant time lag occurs and position stability cannot be ensured
Solution Approach 1:
The patent replaces the manual mechanical input process (reading optical display and entering values via input devices) with an automated electronic data acquisition system. The control system automatically reads measured values from the measuring device via data communication, eliminating the manual input step and its associated time delays.
Solution Approach 2:
The calibration system performs self-measurement and self-recording. The measuring device and control system work together automatically to acquire, store, and process calibration data without requiring operator intervention for data entry, enabling the system to calibrate itself efficiently.
2Measurement precision
If more calibration points are measured to capture nonlinearity, then measurement accuracy improves, but calibration time increases significantly
Solution Approach 1:
The patent enables continuous automated measurement across multiple calibration points without interruption. The control system automatically sequences the measurement process, continuously acquiring data at all calibration points and immediately storing it, eliminating the stop-start nature of manual calibration and maintaining high productivity despite increased measurement density.
Solution Approach 2:
The system pre-configures all calibration points and measurement parameters before the calibration process begins. The control system automatically manages the entire measurement sequence, so no time is lost during calibration for setting up or transitioning between measurement points, allowing dense calibration grids to be executed efficiently.
3Measurement precision
If external force measuring device is temporarily installed in bonding area, then force measurement can be performed, but available space is insufficient in modern double-head bonders
Solution Approach 1:
The patent extracts the measuring device from the bonding area and relocates it to the working area. This separation allows the measuring device to be permanently installed in a space that is always available, while the bonding area remains completely free for its primary function of processing semiconductor components.
Solution Approach 2:
The bondhead serves as an intermediary carrier that transports the bonding tool between the working area (where measurement occurs) and the bonding area (where processing occurs). This allows the measuring device to remain permanently installed in the working area while still enabling measurement during the calibration process.
4Measurement precision
If static measurement with constant current is performed, then stable measured values are obtained, but positioning stability and current constancy are difficult to maintain
Solution Approach 1:
The control system continuously monitors the actual position and current during measurement and uses this feedback to maintain the required stability. The system can detect deviations from the desired static conditions and make real-time adjustments to keep the measurement process stable, ensuring accurate data acquisition.
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 method significantly improves measurement accuracy and reduces calibration time, ensuring precise control of bonding forces and enhancing bonding quality by automating the calibration process and eliminating operator errors.
Implementation Method 1
with a measuring device (1) for determining a bonding force
Implementation Method 2
with a position sensor for detecting a deflection of the spring
Implementation Method 3
with a current sensor for detecting a current used to control the force actuator
Implementation Method 4
The actuator force of a voice coil actuator is linearly related to the current
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to a calibration method for a bonder, wherein characteristics of a force actuator of the bonder are measured and stored in such a way that the force actuator can be controlled optimally during productive operation of the bonder on the basis of the measured data. The invention further relates to a device for fully automatic or partially automatic bonding force calibration.