Methodology and system for wafer-level testing of MEMS pressure sensors
First Claim
1. A method for testing a plurality of pressure sensors on a device wafer, wherein said pressure sensors are located on a first side of a substrate portion of said device wafer, each of said pressure sensors includes a cavity, a port extends through said substrate portion from a second side of said substrate portion to said first side into said cavity, and said method comprises:
- placing a diaphragm of one of said pressure sensors on said device wafer in proximity to a nozzle of a test system;
positioning a seal element surrounding an outlet of said nozzle in contact with said second side of said substrate portion surrounding said port;
applying mechanical force to said seal element to form a pressure seal between said second side of said substrate portion and said seal element;
applying a pneumatic pressure stimulus to said diaphragm via said outlet of said nozzle, wherein said pneumatic pressure stimulus is imposed on said diaphragm via said port and said cavity associated with said one of said pressure sensors; and
measuring a cavity pressure within said cavity in response to said applying said pneumatic pressure stimulus.
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Accused Products
Abstract
A method for testing a plurality of pressure sensors on a device wafer includes placing a diaphragm of one of the pressure sensors on the device wafer in proximity to a nozzle of a test system. A pneumatic pressure stimulus is applied to the diaphragm via an outlet of the nozzle and a cavity pressure is measured within a cavity associated with the pressure sensor in response to application of the pneumatic pressure stimulus. The pneumatic pressure stimulus within the cavity corresponds to the pressure applied to the diaphragm. Methodology is executed to test the strength and/or stiffness of the diaphragm. Additionally, the methodology and test system can be utilized to determine an individual calibration factor for each pressure sensor on the device wafer.
43 Citations
16 Claims
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1. A method for testing a plurality of pressure sensors on a device wafer, wherein said pressure sensors are located on a first side of a substrate portion of said device wafer, each of said pressure sensors includes a cavity, a port extends through said substrate portion from a second side of said substrate portion to said first side into said cavity, and said method comprises:
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placing a diaphragm of one of said pressure sensors on said device wafer in proximity to a nozzle of a test system; positioning a seal element surrounding an outlet of said nozzle in contact with said second side of said substrate portion surrounding said port; applying mechanical force to said seal element to form a pressure seal between said second side of said substrate portion and said seal element; applying a pneumatic pressure stimulus to said diaphragm via said outlet of said nozzle, wherein said pneumatic pressure stimulus is imposed on said diaphragm via said port and said cavity associated with said one of said pressure sensors; and measuring a cavity pressure within said cavity in response to said applying said pneumatic pressure stimulus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for testing a plurality of pressure sensors located on a first side of a substrate portion of a device wafer, each of said pressure sensors including a diaphragm and a cavity, said diaphragm being formed in at least one wall surrounding said cavity, a port extends through said substrate portion from a second side of said substrate portion to said first side into said cavity, and said method comprises:
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retaining said device wafer in a wafer chuck of a test system such that said device wafer is substantially parallel to an X-Y plane of said test system, wherein said device wafer chuck is coupled to a movable X-Y stage; indexing said X-Y stage to place one of said plurality of pressure sensors in proximity to a nozzle of said test system; moving at least one of said nozzle and said device wafer along a Z-axis substantially perpendicular to said X-Y plane to position said diaphragm of said one of said pressure sensors in proximity to said nozzle; sealing said cavity associated with said one of said pressure sensors, said sealing including positioning a seal element surrounding an outlet of said nozzle in contact with a second side of said substrate portion surrounding said port and applying mechanical force to said seal element to form a pressure seal between said second side of said substrate portion and said seal element to thereby seal said cavity; applying a pneumatic pressure stimulus from an outlet of said nozzle to said diaphragm via said cavity, said applying occurring following said sealing, wherein said pneumatic pressure stimulus is imposed on said diaphragm via said port and said cavity associated with said one of said pressure sensors; and measuring a cavity pressure within said cavity in response to said applying said pneumatic pressure stimulus, said measuring occurring while a port into said cavity remains sealed. - View Dependent Claims (12, 13, 14)
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15. A test system for testing pressure sensors on a device wafer, wherein said pressure sensors are located at a first side of a substrate portion of said device wafer, each of said pressure sensors includes a diaphragm and a cavity, a port extends through said substrate portion from a second side of said substrate portion to said first side into said cavity, and said test system comprises:
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a table for retaining said device wafer; a nozzle; an actuator for placing said nozzle and said diaphragm of one of said pressure sensors in proximity to one another; a seal element surrounding an outlet of said nozzle, wherein said seal element is adapted for mechanical contact with said second side of said substrate portion surrounding said port to form a pressure seal between said second side of said substrate portion and said seal element; a fluid supply line in communication with said nozzle for providing a pneumatic pressure stimulus, said pneumatic pressure stimulus being applied to said diaphragm associated with one of said pressure sensors via an outlet of said nozzle, wherein said pneumatic pressure stimulus is imposed on said diaphragm via said port and said cavity associated with said one of said pressure sensors; a pressure transducer for measuring a pressure within said fluid supply line in response to said pneumatic pressure stimulus, said pressure being indicative of a cavity pressure within said cavity; and a controller configured to receive said pressure and ascertain functionality of said one of said pressure sensors in response to said pressure. - View Dependent Claims (16)
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Specification