MEMS Multichip Modules for High-Temperature Probe Card Testing
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Solution Overview
Problem
Existing solutions for two-touchdown testing of 300 mm wafers with many NAND dice face limitations due to mechanical relays' high impedance mismatch, cost, reliability issues, and temperature constraints, as well as the density limitations of daughter boards with active silicon switches.
Innovation Solution
The use of multichip modules with micro-electromechanical switches mounted directly on probe cards, enabling higher data rates and extended temperature ranges, replacing mechanical relays and active silicon switches with micro-electromechanical switches that operate at speeds up to 100 MHz and temperatures from -40°C to 125°C, significantly increasing the number of test sites and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical relays are used in the DUT interface of ATE system, then signal processing between tester and devices under test is enabled, but impedance mismatch increases and data rate is limited to 20 MHz
Solution Approach 1:
The patent replaces mechanical relays with micro-electromechanical switches (MEMS) that have no moving parts. These MEMS switches are integrated into multichip modules mounted directly on the probe card, eliminating the mechanical relay system that caused impedance mismatch and speed limitations. The solid-state nature of MEMS switches provides better electrical characteristics and higher operating frequencies.
Solution Approach 2:
The patent introduces multichip modules with MEMS switches as an intermediary component between the tester and devices under test. These modules are mounted on the probe card and provide signal routing functionality closer to the DUT interface, reducing the electrical distance and improving impedance matching compared to remote mechanical relays.
2Reliability
If mechanical relays are used for signal processing, then testing capability is provided, but cost increases and reliability decreases over time
Solution Approach 1:
The patent replaces mechanical relays with solid-state MEMS switches that have no moving parts, eliminating wear and tear issues. This substitution dramatically improves reliability for high-volume testing while reducing per-unit cost through integration and elimination of mechanical components.
Solution Approach 2:
The patent uses cost-effective MEMS switch implementations that can be manufactured at low cost and integrated into reusable probe cards, providing a more economical solution than expensive mechanical relays while maintaining high reliability over billions of test cycles.
3Temperature
If mechanical relays are used for testing, then signal routing is achieved, but operating temperature is limited to 85° C. or below
Solution Approach 1:
The patent changes the operating temperature parameters by using MEMS switches and multichip modules designed to operate at temperatures up to 125° C. This allows the testing system to handle high-temperature devices and perform thermal characterization testing that was impossible with mechanical relays limited to 85° C.
4Quantity of substance
If daughter boards with active silicon switches are used for multiplexing, then tester pin electronics multiplexing is enabled, but temperature is limited to 85° C. and density is restricted by connector limitations
Solution Approach 1:
The patent replaces active silicon switches on daughter boards with MEMS switches integrated directly on the probe card. This substitution enables higher density arrangements without connector limitations and extends the operating temperature range beyond 85° C.
Solution Approach 2:
The patent moves the switching functionality from a separate daughter board plane to the probe card plane, integrating multichip modules with MEMS switches directly on the probe card. This dimensional integration increases density by eliminating connector interfaces and allows closer placement of switches to test sites.
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 allows for efficient, high-density, and cost-effective testing of 300 mm wafers with NAND devices at higher data rates and broader temperature ranges, improving return on investment and reliability by using micro-electromechanical switches that can handle billions of test cycles.
Implementation Method 1
each of the at least one multichip module comprising a plurality of micro-electromechanical switches between a first set of connectors to the tester and a second set of connectors to the plurality of devices under test
Data Source
AI summary
Apparatus is for processing signals between a tester and devices under test. In one embodiment, the apparatus includes at least one multichip module. Each multichip module has a plurality of micro-electromechanical switches between a set of connectors to the tester and a set of connectors to devices under test. At least one driver is provided to operate each of the micro-electromechanical switches. A method of processing signals between a tester and devices under test is disclosed. In an embodiment, the method includes connecting the tester and the devices under test with at least one multichip module. Each of the at least one multichip module has a plurality of micro-electromechanical switches between a set of connectors to the tester and a set of connectors to the devices under test. The method includes operating each of the micro-electromechanical switches. Other embodiments are also disclosed.