Prober Stage Cooling and LED Heating for Wafer Inspection
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Solution Overview
Problem
Existing electronic device inspection apparatuses face challenges in controlling the temperature of semiconductor wafers or carriers locally, leading to thermal loads being applied to adjacent devices, which can cause issues during inspection and increase packaging costs due to decreased yield.
Innovation Solution
A placement stand with a cooling mechanism made of light-transmitting material and a light irradiation mechanism using LEDs, allowing for controlled temperature management by irradiating light to specific areas while cooling the entire object, thereby minimizing thermal loads on adjacent devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a coolant flow path or heater is disposed in the stage to control the temperature of the wafer, then the temperature of the wafer can be controlled, but it is difficult to control the temperature locally and thermal load is applied to adjacent electronic devices
Solution Approach 1:
The patent applies local quality by enabling different regions of the wafer to have different temperature conditions. The light irradiation mechanism selectively heats only the specific area where the probe contacts the electronic device, while the coolant flow path cools other regions. This allows the inspected device to be heated to operational temperature without subjecting adjacent devices to thermal load, thereby resolving the contradiction between temperature control and thermal load prevention.
Solution Approach 2:
The patent segments the temperature control function into two independent systems: a light irradiation mechanism for localized heating and a coolant flow path for overall cooling. This segmentation allows independent control of temperature in different regions, enabling the inspected device to be heated without affecting adjacent devices thermally.
2Object-affected harmful factors
If the entirety of the wafer is cooled by a coolant flow path, then thermal load to adjacent devices is avoided, but implementation voltage cannot be applied to the electronic device under inspection
Solution Approach 1:
The light irradiation mechanism provides localized heating to the specific area where the electronic device under inspection is located, while the coolant flow path maintains cooling of the overall wafer and adjacent devices. This localized heating enables implementation voltage to be applied to the inspected device for reliability testing without subjecting adjacent devices to thermal load, thereby resolving the contradiction between yield detection and thermal load prevention.
3Temperature
If miniaturization of coolant flow path or heater is attempted for local temperature control, then local temperature control becomes possible, but device complexity increases
Solution Approach 1:
The patent introduces light as an intermediary for localized heating. Instead of miniaturizing complex cooling structures, the light irradiation mechanism selectively heats only the required area, while the existing coolant flow path handles overall temperature control. This intermediary approach achieves local temperature control without increasing the complexity of the cooling system.
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 solution enables precise temperature control of electronic devices during inspection, allowing for the application of higher implementation voltages without affecting adjacent devices, thereby reducing packaging costs and improving yield by identifying potential issues before packaging.
Implementation Method 1
a coolant flow path through which a coolant flows
Implementation Method 2
a light irradiation mechanism which irradiates light to the inspection object... the inspection object is heated
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Provided is an electronic device inspecting apparatus that suppresses cost increase. A prober 10 is provided with a stage 11 on which a carrier C or a wafer W is placed. The stage 11 is provided with a stage cover 27 on which the carrier C is placed, a cooling unit 29 in contact with the stage cover 27, and an LED irradiation unit 30 facing the carrier C across the stage cover 27 and the cooling unit 29. Each of the stage cover 27 and the cooling unit 29 is formed of a light transmitting material. A light-transmitting coolant flows in a coolant flow path 28 in the cooling unit 29. The LED irradiation unit 30 has a plurality of LEDs 32 oriented to the carrier C. The carrier C is formed of a glass substrate 24 having a substantially disc-like shape. A plurality of electronic devices 25 are arranged on a surface of the carrier C at predetermined intervals therebetween.