Contactor Assembly With Interposer For IC Testing
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Solution Overview
Problem
High-speed integrated circuit testing requires accurate and reliable contact probes to handle steep step-like voltages and currents, but existing systems suffer from parasitic impedance and ground noise due to long electrical paths and parasitic capacitance, leading to potential rejection of functional devices.
Innovation Solution
A contactor assembly with a stack of laminates and a cover that houses bifurcated Kelvin contacts, allowing for staggered placement of probes and integration of conductive pads and compressive elements to minimize impedance and inductance, enabling precise electrical connections and signal coupling through a load board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If long electrical paths are used to connect test circuitry to semiconductor device terminals, then the testing apparatus can accommodate more components and provide better mechanical support, but parasitic impedance and inductance increase causing signal distortion and ground noise
Solution Approach 1:
The patent introduces an interposer as an intermediary component between the contactor and the semiconductor device. This interposer includes a first substrate with first contact pads and a second substrate with second contact pads, creating multiple intermediate connection points. By distributing the electrical connection across multiple shorter paths through the interposer rather than using single long paths, the patent reduces parasitic inductance and impedance while maintaining mechanical support structure.
Solution Approach 2:
The patent segments the electrical connection path by using multiple contact probes (both contact probes and sense probes) distributed across multiple terminals of the semiconductor device. Each probe creates a separate, shorter electrical path from the contactor to the load board, rather than using a single long path. This segmentation reduces the overall parasitic inductance and impedance by dividing the long path into multiple shorter segments.
2Productivity
If steep step-like voltages and currents are applied through contact probes for high-speed testing, then testing speed increases exceeding 5000 devices per hour, but signal distortion and ground noise increase due to parasitic capacitance and inductance
Solution Approach 1:
The interposer acts as a mediator that distributes the steep step-like signals through multiple shorter electrical paths. By using the interposer's multiple contact pads connected to different semiconductor device terminals, the patent reduces the effective inductance and capacitance in each signal path, enabling high-speed testing while maintaining signal integrity and reducing ground noise.
Solution Approach 2:
The patent merges multiple contact probes and sense probes into a unified contactor assembly that simultaneously contacts multiple semiconductor device terminals. This merging allows parallel testing of multiple devices or multiple parameters of a single device, increasing productivity while the distributed nature of the probes reduces parasitic effects in each individual signal path.
3Reliability
If multiple contact probes are used to contact each terminal of the semiconductor device, then testing reliability improves through accurate measurement, but device complexity increases
Solution Approach 1:
The patent merges multiple contact probes and sense probes into a single integrated contactor assembly. This assembly is held together by a contactor holder that secures all probes in their proper positions and orientations. By combining multiple probes into one assembled unit, the patent simplifies the overall device complexity compared to having separate probes and holders, while maintaining the reliability benefits of multiple contact points.
Solution Approach 2:
The contactor holder serves multiple functions: it holds the contact probes in proper positions, provides mechanical support, and facilitates electrical connections through the load board. This multi-functionality reduces the need for separate components, thereby reducing overall device complexity while maintaining testing reliability through the use of multiple probes.
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 reduces signal distortion and noise, ensuring accurate and reliable testing of semiconductor devices by effectively managing parasitic impedance and inductance, thereby minimizing reject rates and maintaining quality assurance.
Implementation Method 1
a compressive element extending through the stack in register with the conductive pad
Implementation Method 2
a conductive pad on a rear face of the cover facing the top laminate; and a load board, wherein the distal ends of the plurality of contact probes are operable to terminate on the load board
Data Source
AI summary
The present invention provides a contactor assembly (100,200,300) for testing of semiconductor devices (DUT). The contactor assembly (100,200,300) includes a plurality of probes (20,22,24), a contactor holder (150,350) and a cover (180,280) shaped and dimensioned to fit on the contactor holder (150,350). The contactor holder (150,350) is a stack of laminates. A top laminate (156,256) of the contactor holder (150,350) has apertures (158,258). A contact probe (22) is seen through one aperture (158,258). On a rear face of the cover (180,280), there is at least one conductive pad (186) in register with an aperture (158,258). Each aperture (158,258) is operable to house a surface-mount electric component (160), such as a resistor, capacitor or inductor, and a conductive compressive element (162). In another embodiment, a front side of a cover (280) has a connector (285) in electrical communication with a conductive pad (186). In use, a signal in one probe (22) is operable to be: coupled to a signal in another probe; filtered from a separate probe; or compensated for impedance, capacitance or inductance; such coupling, filtering or compensating is made possible by series and/or parallel connection of the electric component (160).