DE102009016789B4 - Device of a test-independent test system for electrical functional test of one or both sides electrically contactable test points and method thereto - Google Patents

Abstract

Device of a test system independent of the test object for the electrical function test of test points (a) which can be electrically contacted on one or both sides, the test points (a) being provided by conductor network end points or single point networks from an unpopulated electrical circuit carrier (A) to be tested, comprising a measuring sensor (C, B) , wherein the sensor (C, B) has grid contact points (d, g) which are arranged in a uniform XY grid, the grid contact points (d, g) being electrically conductive, and wherein the grid contact points (d, g) are mutually electrical are isolated, and the device further comprises a measuring and control unit (F) to control the grid contact points (d, g) individually or in groups by means of an active switching matrix (C), to one or more conductive connections between the electrical circuit carrier to be tested (A) and the measuring and control unit (F), the sum of the grid contact point width (d) and the distance (e) to an adjacent grid contact point (d, g) is less than the smallest distance (b) between two test points (a), and the distance (e) between two adjacent grid contact points (d, g) is smaller than the areal extent (c) of a test point (a), and the grid contact points (d, g) to be controlled are controlled by the measuring and control unit (F) on the basis of known test data of the electrical circuit carrier (A) to be tested, to test specifically for the necessary electrical connection, interruption and short circuit.

Description

EP 0 369 112 A1 shows an adapter assembly for electronic tester for printed circuit boards. The test device must be adapted individually for each type of test specimen by creating a test specimen-specific adapter plate.

DE 100 43 782 C2 shows a method for testing printed circuit boards. In the presented method, a position detection is performed in order to contact a test-speci fi c contact in a position-specific manner.

GB 2 156 532 A shows a system for testing printed circuit boards. In the presented system, a test-specific test circuit board is used.

The invention has the object to provide a test-independent system. The object is achieved by a device according to claim 1 or by a method according to claim 7.

The sensor (C, B) consists of an active switching matrix (C) and a contact mat (B) applied thereto, wherein the two uniformly arranged, electrically conductive raster contact points (d) and (g) connect to each other in a reproducibly electrically conductive manner. The switches (S1 to Sn) can be controlled individually or in groups via the control lines (s1 to sn) with the aid of the control and measuring electronics F and thus via the measuring lines (m1 to mn) the raster contact points (d) with the evaluation electronics ( F) electrically conductively connect.

The contact mat (B) establishes the mechanical connection between the switching matrix (C) and the test object (A) and the electrical connection between the raster contact point (d) and test points (a) to be tested. Sufficient compressibility of the contact mat (B) in the Z direction compensates for the usual surface structures of the test object (A). In the X and Y direction, the contact mat (B) is sufficiently dimensionally stable. All grid contact points (d) of the contact mat (B) are electrically isolated from each other.

An electrically measurable current flow occurs when the circuit is closed via the interface E, selected switches (S1 to Sn), raster contact point (d) and (g) and to be tested interconnects. Current flow and electrical resistances are measured via the measuring leads (m1 to mn). Contact and contact resistance are low, reproducible and can therefore be charged or by known metrological methods such. B. four-wire technology optionally be compensated.

With the help of the known test data (Gerber files, CAD data o. Ä) and introduced at the beginning of the test history position detection, the actual circuit pattern is calculated and controlled necessary for the production of closed circuits switch the active switching matrix, which selectively connects to the test points (a) make the test piece (A). Thus, all traces on the device under test (A), individual test points (a) and / or interconnected network endpoints are tested for necessary electrical connection, open circuit and short circuit.

In one-sided contactable interconnects in the Good test, a current flow from the measuring and control unit (F) via the interface (E), the transducer (B, C), the test track of the test specimen (A) and the same transducer (B , C) back again. In both sides contactable interconnects of the current flows through the second transducer to the measuring and control unit (F) back.

Testable are contactable on one or both sides, electrical circuits whose smallest actual Prüfpunktabstand (b) is greater than the sum of the raster contact point diameter (d) + Rasterkontaktpunktabstand (e) of the contact mat (B). The test point area (c) must be greater than the smallest distance between two grid contact points (d) of the contact mat (B).

The position of the test object (A) on the contact mat (B) is determined by means of at least two identifiable interconnect network end points (a) on the test object (A) by targeted application of test currents and known approximation methods. Special edition or landing aids are not necessary.

The presented invention allows at least the following evaluations: nominal / actual comparison of electrical function values; Interruption test; Short-circuit test; Detection and compensation of linear misalignments or angular misalignments and distortions in the circuit pattern using known trigonometric calculations. All printed circuit boards are testable, as far as the basic requirements for the testability of the test object (A), as described above, are fulfilled.

The test system-independent test system presented here achieves high test speeds, can be automated and thus offers itself for the electrical function test of standard mass production, small series and prototype tests of bare one- and two-sided electrical circuit carriers such as circuit boards, substrates, ceramics, bonding and flex circuits. Mechanical stresses on test points do not arise. Lower requirements for the contact pressure reduce the mechanics and thus size and cost of test equipment according to this invention principle.

Claims (12)

Device of a test-independent test system for the electrical function test of test points (a) which can be electrically contacted on one or both sides, the test points (a) being given by conductor network end points or single-point networks of an unpopulated electrical circuit carrier (A) to be tested, comprising a sensor (C, B) wherein the sensor (C, B) has raster contact points (d, g) arranged in a uniform XY-grid, wherein the raster contact points (d, g) are electrically conductive, and wherein the raster contact points (d, g) are mutually electric and the apparatus further comprises a measurement and control unit (F) for driving the raster contact points (d, g) individually or in groups by means of an active switching matrix (C) to form one or more conductive connections between the electrical circuit substrate to be tested (A) and the measuring and control unit (F) produce, the sum of grid contact point width (d) and the distance (e) to an adjacent grid contact point (d, g) is less than the smallest distance (b) of two test points (a), and wherein the distance (e) between two adjacent grid contact points (d, g) is smaller than the areal extent (c) of a test point (a), and wherein the to be controlled raster contact points (d, g) are driven based on known test data of the electrical circuit substrate to be tested (A) of the measuring and control unit (F), to specifically test for necessary electrical connection, interruption and short circuit. Apparatus according to claim 1, characterized in that the device comprises a contact mat (B), the mechanical connection between the switching matrix (C) and the electrical circuit carrier to be tested (A) and the electrical connection between the grid contact point (d, g) and A sufficient compressibility of the contact mat (B) in the Z direction surface structures of the electrical circuit substrate to be tested (A) compensates, wherein the contact mat (B) in the X and Y direction is dimensionally stable, and wherein all Raster contact points (d) of the contact mat (B) are electrically isolated from each other. Apparatus according to claim 2, characterized in that an electrically measurable current flow with closed circuit via an interface (E), selected switches (S1 to Sn), raster contact points (d, g), as well as to be tested interconnects, arises, via the measuring lines ( m1 to mn) current flow and electrical resistances are measured. Apparatus according to claim 3, characterized in that the planar format of the sensor (C, B) is greater than the planar format of an electrical circuit substrate to be tested (A). Device according to one of claims 1 to 4, characterized in that by the minimum pitch (vector F) of the measuring transducer (C, B), a plurality of grid contact points (d) of the contact mat (B) a test point (a) of the electrical circuit substrate to be tested ( A) contact. Device according to one of claims 1 to 5, characterized in that the test system has a position detection for detecting the position of the electrical circuit substrate to be tested (A). Method for a test-independent test system for the electrical function test of test points (a) which can be electrically contacted on one or both sides, the test points (a) being given by conductor network end points or single-point networks of bare electrical circuit carriers (A), the test system having a sensor (C, B) wherein the sensor (C, B) has raster contact points (d, g) arranged in a uniform XY raster, the raster contact points (d, g) being electrically conductive, and wherein the raster contact points (d, g) are mutually opposed are electrically isolated, and the apparatus further comprises a measurement and control unit (F) to the raster contact points (d, g) individually or in groups by means of a switching matrix (C) to control one or more conductive connections between the electrical circuit substrate to be tested (A) and the measuring and control unit (F), comprising the steps of: Driving of test to be tested grid contact points (d, g) based on known test data of the electrical circuit substrate to be tested (A), which correspond at least to a test point (a) from the previously obtained test data of an unpopulated circuit substrate (A) to targeted to necessary electrical connection, open circuit and short circuit test, Measuring a current or resistance between the grid contact points to be tested (d, g). The method of claim 7, further comprising the step of: detecting the position of the electrical circuit substrate to be tested (A), • wherein the detected position in the calculation of raster contact points (d, g), which correspond to the test points (a), is taken into account. A method according to claim 7 or 8, characterized in that in one-sided contactable interconnects in good test a current flow from the measuring and control unit (F) via an interface (E), the sensor (C, B), the conductor track network to be tested to be tested electrical circuit substrate (A) and the same sensor (B, C) takes place back, while in both sides contactable interconnects in good test a current flow from the measuring and control unit (F) via the interface (E), the sensor ( C, B), the conductor track network to be tested of the electrical circuit substrate (A) to be tested and the second sensor (C, B) to the measuring and control unit (F) is back again. Method according to one of claims 7 to 9, further comprising the step: Detecting the position of the electrical circuit substrate (A) to be tested, the position of the electrical circuit substrate (A) to be tested being tested on a contact mat (B) with the aid of at least two identifiable interconnect network end points (a) on the electrical circuit substrate (A) to be tested determines the specific application of test currents and the use of approximation methods, • wherein the detected position in the calculation of raster contact points (d, g), which correspond to the test points (a), is taken into account. Method according to one of claims 7 to 10, characterized in that a detected conductor pattern offset is determined against target data. A method according to claim 11, characterized in that the detected circuit pattern offset is compared with target data evaluated and at an offset greater than a predetermined value of the electrical circuit substrate to be tested (A) is detected as defective.

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