Wafer Placement Machine Pneumatic Carrier Fixation
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Solution Overview
Problem
The increasing miniaturization of electronic components poses high demands on placement accuracy, which existing assembly machines struggle to meet due to temperature instability and mechanical distortion, especially when handling unpackaged semiconductor chips during the embedded wafer level package process.
Innovation Solution
A placement machine with a pneumatic interface for vacuum fixation of carriers, a temperature control device to maintain constant temperature, and a positioning system with optical markings for precise alignment, ensuring high accuracy and stability during chip placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mechanical clamping mechanisms are used to fix the carrier, then the device complexity is reduced, but the temperature stability and positioning accuracy deteriorate due to thermal expansion differences
Solution Approach 1:
The patent employs a pneumatic interface with a vacuum field to fix the carrier to the carrier receiving device. The vacuum field is generated by a negative pressure source that creates a pressure difference between the vacuum field and the ambient atmosphere, causing the carrier to be firmly held against the carrier receiving device without mechanical contact. This pneumatic fixation method eliminates thermal expansion issues associated with mechanical clamping while maintaining high positioning accuracy.
Solution Approach 2:
The patent changes the physical state parameter from mechanical force to pressure differential. By controlling the negative pressure level in the vacuum field, the system can dynamically adjust the fixation strength while maintaining thermal stability. The pressure parameter allows for precise control of carrier positioning without the thermal expansion problems inherent in mechanical systems.
2Stability of the object's composition
If the carrier is held at ambient temperature, then the device complexity is reduced, but the positional stability deteriorates due to thermal expansion and contraction
Solution Approach 1:
The patent introduces active temperature control to maintain the carrier receiving device at a constant temperature, preventing thermal expansion and contraction that would cause positional drift. The temperature control device monitors and adjusts the temperature parameter to keep it within a specified range, ensuring carrier position stability throughout the chip placement process.
Solution Approach 2:
The temperature control system operates with feedback control, continuously monitoring the temperature of the carrier receiving device and adjusting heating or cooling as needed to maintain the setpoint temperature. This closed-loop control ensures that thermal fluctuations are compensated in real-time, maintaining positional stability.
3Manufacturing precision
If the chip placement process is performed quickly, then the productivity is improved, but the placement accuracy deteriorates due to insufficient time for thermal and positional stabilization
Solution Approach 1:
The patent performs preliminary stabilization of the carrier position and temperature before the chip placement process begins. The carrier is firmly fixed using vacuum field, and the temperature control device pre-establishes the optimal temperature condition. This preliminary preparation ensures that during the subsequent rapid chip placement, no thermal or positional drift occurs, allowing high speed without sacrificing accuracy.
Solution Approach 2:
The pneumatic vacuum field provides immediate and firm carrier fixation that prevents any movement during rapid chip placement operations. Unlike mechanical systems that may have play or thermal expansion, the vacuum field maintains constant positioning force throughout the process, enabling high-speed placement while maintaining accuracy.
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 solution achieves extremely high placement accuracy and temperature stability, preventing mechanical distortion and positional shifts, even under fluctuating ambient temperatures, thereby enhancing the precision of electronic component assembly.
Implementation Method 1
The carrier receiving device has a pneumatic interface by means of which a negative pressure can be applied to a surface of the carrier
Implementation Method 2
The placement machine also has a temperature control device which is thermally coupled to the carrier receiving device and which is set up to keep the carrier receiving device at least approximately at a constant temperature
Data Source
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AI summary
A placement machine (110) and a method for placing unpackaged chips (282) onto a carrier (190) are described. The placement machine (110) comprises (a) a feeding device (140) for providing a wafer (180) containing a plurality of chips (282); (b) a carrier holding device (130) for receiving the carrier (190) to be populated, which has previously precisely measured optical structures (234); and (c) a placement head (120) for picking chips from the provided wafer (180) and placing the picked-up chips (282) at predefined placement positions on the carrier (190). The carrier holding device (130) has a pneumatic interface (232) by means of which a vacuum can be applied to a surface of the carrier (190).