Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
  • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
  • B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
  • B07C5/34—Sorting according to other particular properties
  • B07C5/344—Sorting according to other particular properties according to electric or electromagnetic properties
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
  • G01R1/02—General constructional details
  • G01R1/06—Measuring leads; Measuring probes
  • G01R1/067—Measuring probes
  • G01R1/06794—Devices for sensing when probes are in contact, or in position to contact, with measured object
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
  • G01R31/28—Testing of electronic circuits, e.g. by signal tracer
  • G01R31/2851—Testing of integrated circuits [IC]
  • G01R31/2886—Features relating to contacting the IC under test, e.g. probe heads; chucks
  • G01R31/2891—Features relating to contacting the IC under test, e.g. probe heads; chucks related to sensing or controlling of force, position, temperature

Definitions

• the invention relates to the field of testing equipment for electronic components and more particularly to the field of aligning test contacts.
• Miniature electronic components are tested in a variety of ways.
• One group of testing that relates to multiple layer capacitance chips (MLCC) involves electrical testing, including, but not limited to cap testing, cross checking, testing for leakage current, and testing for break down voltage.
• MLCC multiple layer capacitance chips
• FIG. 2 herein, which is a modification of Figure 2 from U.S. Patent No. 5,842,579, an electronic component is captured in a test plate 12.
• a vacuum source passes a vacuum through a base plate to draw electronic components into component pockets on test plate 12.
• a stepper motor 16 is operatively connected to test plate 10 to index test plate 12 such that electronic components are delivered to test heads 18 located on testing machine 10. Frequently the test heads are closely spaced. Each test head 18 may include a plurality of test contacts 20, each test contact configured to conduct the same test. After the testing is complete, test plate 12 continues to index to deliver tested components to blow off zone 22. In blow off zone 22 the electronic components are blown out of the component pocket that contains them and appropriately sorted as a function of the test results.
• Electronic component testers may be adjusted and/or calibrated such that the individual test contacts properly align over component pockets such that when the test plate 12 is indexed the electronic components are delivered to the contacts so that an acceptable electrical connection is achieved.
• One way to align the test contacts with the test component pockets is the use of a fixture to assist the placement of test heads. Proper alignment can be more accurately realized by checking the alignment of the test heads with a borescope. In particular, the borescope would be used to visually inspect each contact and its relative positioning against the component pockets on the test plate. This evaluation would include inspection of theta and skew. If a determination was made that the test contact or test head was misaligned, alignment could be achieved by known adjustments.
• test heads may be closely spaced, use of borescope may be difficult and time consuming. A need has arisen to improve the process of determining the alignment of the contact heads.
• a method for determining a position of a plurality of test contacts on an electronic component testing machine includes a component test plate configured to retain a plurality of electronic components.
• the test plate is movable between a plurality of index positions such that electronic components electrically connect to the testing contacts at each index position.
• the electrical connectivity between an electronic component and a testing contact is measured at a plurality of microsteps where each the microstep is a fraction of an index.
• a plurality of electrical measurements is provided for an individual test contact. The plurality of measurements is evaluated to determine the alignment of the test contact.
• a method for aligning at least one of a plurality of test contacts on an electronic component testing machine is also provided.
• the component testing machine includes a test plate configured to retain a plurality of electronic components and the test plate is movable between a plurality of index positions. Electronic components electrically connect to the plurality of testing contacts at each index.
• the method includes measuring the electrical connectivity between the electronic component and a testing contact at a plurality of microsteps and a plurality of electrical measurements is provided for a single test contact. The test contact is adjusted based on the plurality of electrical measurements.
• An electronic component testing machine includes a test plate configured to retain a plurality of electronic components and includes a plurality of test heads. Each test head has a plurality of test contacts.
• the test plate is operatively connected to a drive mechanism such that the test plate is movable between a plurality of index positions to deliver a plurality of electronic components to one of the test heads.
• a motion controller is configured to move the test plate in microsteps where the microsteps are a distance less than an index.
• a controller is configured to take multiple electrical measurements between an electronic component and an individual test contact for each microstep resulting in a plurality of electrical measurements. Means are provided to adjusting the test contact to bring it into alignment based on the electrical measurements
• Figure 1 is a flow chart depicting the process of determining the alignment of test contacts and including an adjustment of the test contacts
• Figure 2 is a simplified perspective view of an example of a prior art electrical testing machine
• Figure 3 is a close up plan view of a test pocket positioned over a pair of blow off holes;
• Figure 4 illustrates an optionally graphical output depicting the relative alignment of a plurality of test contacts on a plurality of test heads;
• Figure 5 is a representative example of an adjustment mechanism that will adjust positioning of a test head.
• Figure 6 is a simplistic illustration of different pattern profiles of microstep contact measurements for a test head.
• a test plate will index from test head to test head. At each test head an electrical measurement will be made. It has been discovered that by dividing the index into a plurality of microsteps an electronic component can be swept underneath a test contact to evaluate the location of a test contact.
• the location of the electronic component may be measured relative to a fixed position on the test machine. This fixed position may be at least one blow off hole positioned on a base plate of the test machine. Other fixed locations may be utilized as well. The fixed position may be correlated against the position of a motor driving the test plate to provide a centerline.
• both a loaded and an unloaded centerline may be provided.
• a determination may be made whether an electrical connection exists between the electronic component and the test contact. Based on the positioning of the plurality of electrical measurements relative to either centerline conclusions may be drawn with respect to alignment.
• the data derived from the measurements may be graphically presented to a user such that the user can draw conclusions with regard to alignment, or the system may evaluate the data and inform the user whether adjustments are necessary and if so what those adjustments are.
• a test mode is enabled.
• sample components are loaded into test plate 12.
• a motion controller 17 divides each index into a plurality of microsteps. These microsteps may be defined by motor steps of a stepper motor and may be of an arbitrary distance.
• an index may be approximately 1.8 degrees.
• the index of 1.8 degrees may be divided into 200 microsteps, thus enabling the test plate to advance .009 degrees for each microstep.
• the microstep may be a larger or smaller fraction of the index size.
• test plate is advanced by the above described microstep amounts.
• the alignment system attempts to measure the electronic connection between a test contact 20 and the electronic component for each microstep. In one example the measurement is merely binary, meaning the system determines, yes or no, whether a connection has been made.
• the alignment of the test contact is determined. The alignment may be determined either automatically or with reference to a graphic representation of data.
• test machine 10 further includes controller 19 configured to receive the data from act 34 and either graphically presents it, as in Figure 4, or makes other calculations. Controller 19 may be part of an overall controller for machine 10 or may be a separate controller.
• FIG. 4 With reference to Figure 4 there is shown a graphical representation of the output of a microstep evaluation of the alignment of the plurality test contacts.
• the evaluation of nine different contact heads 40, 41, 42, 43, 44, 45, 46, 47, and 48.
• Each contact head includes a plurality of contacts, e.g. 50, 51, 52, 53, 54, 55, 56, and 57 which have each been individually evaluated.
• Another example of an evaluation an individual head is seen at 58.
• the vertical bar referenced as 58 represents a plurality of successful microstep connections between points A and B.
• Individual contacts may be evaluated to determine whether the connection between the test contact and the electronic component is consistent.
• head 59 there is shown a collection of microstep connections where for a portion of the microsteps e.g. 60 where no electrical connection could be made between the test contacts and the electronic component. This illustration would inform the operator that there was intermittent contact between the test contact at 59 and its associated component. An operator may remedy this in a variety of ways including replacement of the test contact at 59.
• Figure 4 further illustrates an unloaded nominal center indicator line 70.
• Unloaded nominal center indicator line 70 references the positional centerline of the component pocket when the test plate is moving and unloaded. The measurement is made from a fixed position on the machine when the test plate is unloaded and moving.
• FIG. 3 One example of determining a centerline is shown in Figure 3.
• a pair of blow off holes 23 may be observed and positionally correlated against a motor count location.
• the number of motor counts per angle of rotation of the test plate may be determined.
• the component pockets 21 center themselves over the blow off holes 23 at a repeatable motor count.
• this repeatable motor count is arbitrarily set at a zero motor count when the test plate is rotating and empty, as noted by reference numeral 70. It has been observed that in operation of certain electronic component testing machines, such as the model 3430 as sold by Electro Scientific Industries, Inc., the assignee of the instant application, a dynamic shift offset from the centerline occurs as the test plate is loaded with electronic components.
• the rows of component pockets center themselves over the blow off holes 23 at a slightly different motor count when loaded.
• One cause of this dynamic shift is the vacuum utilized to retain the electronic component pockets.
• the dynamic shift was measured as approximately 15 positive motor counts.
• a dynamic centerline 71 may be provided.
• An upper connect limit 72 and a lower contact limit line 73 may also be provided.
• the upper contact and lower contact limit lines provide suggestive limits where the test components within which component pockets 21 should be found.
• a connection between the electronic component and the test contacts is expected to occur between a positive 30 motor counts to a minus 15 motor counts.
• act 37 queries as to whether the test heads are aligned. If the test heads are not aligned, the test heads may be aligned at act 38.
• Act 38 involves adjusting the test contacts and/or test head such that they would be properly aligned with the test component received in the component pocket 21 in the test plate 12. With reference to the example of Figure 4 one way to make this adjustment would be as follows. Looking to the microstep measurements taken at 48 it can be seen that the measurements are biased in a leading direction. At least some of the microstep measurements in the example did not achieve a connection at the dynamic centerline 71. Thus an adjustment may be made to shift the test head in the direction of arrow "C".
• test head 18 including a plurality of test contacts 20.
• Test head 18 is illustrated with reference to a test plate 12 and component pockets 21.
• test head 18 may include adjustments for y skew 75, a y adjustment 77 and a theta adjustment 79. Movement of the aforementioned adjustments in the example of Figure 5 will move test head 18 in the y skew direction 76, the y direction 78 and the theta direction 80.
• the resulting data may inform a user of adjustments to a test head 18 to improve the alignment of the test head relative to the connect pockets.
• alignment information is graphically displayed to a user who may then interpret the data and adjust the test head.
• the measurement data may be mathematically interpreted and a user may be specifically informed of the adjustment to bring the test head into alignment. For example, this adjustment may inform the user to turn the theta adjustment one turn clockwise.
• the measurement results are preferably in a tapered pattern. This tapered pattern is a function of test plate 12 being circular.
• y skew adjustment 75 affects the taper of the measurements.
• the y skew is correct for a circular test plate.
• y skew is clockwise oriented and needs to be adjusted counter clockwise.
• y skew is counter clockwise oriented and needs to be adjusted clockwise.
• act 32 may be reinitiated to confirm alignment. Reinitiating act 32 may not be necessary and may depend on customer preferences. If the query at act 37 indicates alignment, either determined automatically or by reference to a graphic illustration, the process is complete at act 39.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• General Engineering & Computer Science (AREA)
• Testing Of Individual Semiconductor Devices (AREA)
• Testing Electric Properties And Detecting Electric Faults (AREA)
• Measuring Leads Or Probes (AREA)
• Tests Of Electronic Circuits (AREA)
• Testing Or Measuring Of Semiconductors Or The Like (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (6)

Families Citing this family (5)

Family Cites Families (8)

• 2007
  • 2007-08-14 US US11/838,706 patent/US7557594B2/en active Active
• 2008
  • 2008-08-13 JP JP2010521141A patent/JP5324577B2/ja not_active Expired - Fee Related
  • 2008-08-13 CN CN200880103158.4A patent/CN101779135B/zh not_active Expired - Fee Related
  • 2008-08-13 WO PCT/US2008/073048 patent/WO2009023727A2/en not_active Ceased
  • 2008-08-13 TW TW097130834A patent/TWI429929B/zh not_active IP Right Cessation
  • 2008-08-13 KR KR1020107002408A patent/KR101209556B1/ko not_active Expired - Fee Related
• 2009
  • 2009-05-13 US US12/465,089 patent/US7750653B2/en active Active

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