KR100368898B1 - Method and apparatus for testing electronic devices - Google Patents

Abstract

The test assembly used to test electronic devices, preferably IC circuit devices installed on the surface, includes a carrier 4 whereby the device 2 picks up against the lead 6 on the printed circuit board 5. Is taken and maintained. The printed circuit board 5 includes at least one cavity 9 below the contact lead 6 in the circuit board in the region in which the element 2 is held. The pressure pad 7 is provided in the cavity 9 between the lower part of the cavity and the contact lead 6 in order to make the elasticity of the lead 6 constant.

Description

Method and apparatus for testing electronic devices

Electronic devices such as IC circuits are currently being electrically tested using specially designed contactors, and the IC circuits are temporarily placed in the contactors without soldering during the electrical test. There is no increasing development of test methods for small, high-speed surface-mount devices that respond to new demands, increasing uncertainty when testing devices. As a result, most of the devices are discarded from the production line. For example, when measuring dynamic parameters such as weak functional tests, transmission delays or high frequency oscillations, the true performance of the device is often difficult to obtain due to the mechanical structure of the test sockets. Errors in the measurement results are mostly due to stray capacitance of the test sockets in the measurement loop. The internal resistance and contact resistance of the test socket are also caused by incorrect measurement results when measuring static parameters.

U.S. Patent 4,754,555 discloses a device for checking the coplanarity of an IC capsule. In particular, such a device is for checking whether the legs of the IC capsule have the same length. The IC capsule is placed under pressure in a socket assembly included in such a device. The socket assembly includes resilient elements corresponding to the legs of the IC circuit, each of which has a sufficient length so that the legs come into contact with the elastic device when pressure is applied on the IC circuit. The elastic device is in contact with a so-called PC card containing control logic. This device indicates when a contact is made between a leg and a PC card. This device is not used to electrically test the functionality of the circuit. This device itself is relatively complicated and expensive because of the large number of elements.

U.S. Patent No. 4,866,374 discloses a so-called contactor assembly. This contactor is mounted on the circuit card to connect the circuit card with a surface mounted device under test (DUT). Such an assembly is also relatively complicated and expensive because of the large number of devices included therein.

Test sockets configured similarly to the test socket shown in FIG. 1 are currently provided by a number of different suppliers. The contact pressure required for the conductors on the device 2 is achieved with the help of a spring segment 3 similar to that shown in FIG. Such segments are punched, cut or etched from an elastic metal material, such as phosphor bronze, beryllium copper, and the like. In order to obtain efficient attachment and proper contact pressure, the structure needs to be expanded relatively geometrically. The segments are arranged adjacent to each other at intervals corresponding to the connections of the elements. As the size of such devices is decreasing, the segments are gradually placed closer to each other, resulting in undesirable stray capacitance between the conductors.

None of the above-mentioned publications discloses testing a circuit element directly on a circuit card.

DE-C1-3 636 361 discloses an apparatus for testing surface mounted circuits directly on a circuit card. Such a device is intended for insertion into a heating cabinet and includes a circuit card, a receiving plate having recesses corresponding to the circuit, and a press plate having a spring element corresponding to the circuit. press plate). Such cards and plates include suitable guide and latching means for guiding and securing these cards and plates together. When testing the circuit, the circuits must be collected and placed in the recess, then the circuit card, the circuit receiving plate and the press plate are put together to align and lock the receiving plate together between the circuit card and the press plate. The circuit is then pressed against the circuit card by a spring element. Such devices are simple in structure and inexpensive, but nevertheless unnecessarily comprise a large number of elements. Test methods applied outside of the heating cabinet also include a number of unnecessary steps.

None of the known documents related to this technique discloses a circuit card that does not require a socket for a device that is specifically designed and tested for the purpose of testing. No other method is described that allows the device to be tested quickly and simply directly on a circuit card.

The present invention relates to methods, devices and circuit cards for testing IC circuits, in particular electronic devices such as surface mount devices.

1 is a cross-sectional view of the known test socket described above.

2 is a front cross-sectional view of the apparatus of the present invention according to the first preferred embodiment.

3 is a front cross-sectional view of a second preferred embodiment of the device of the present invention.

4 is a cross-sectional view of the device shown in FIG. 3.

FIG. 5 is a view from above of a portion of the apparatus of FIG. 4; FIG.

It is an object of the present invention to improve measurement accuracy over known techniques when testing electronic devices on a circuit to be tested.

Another object is to provide an electronic device test apparatus including relatively few components.

These objects are achieved by a device comprising a component carrier, which holds the device with respect to the circuit card to be tested and holds the device, the card having a contact conductor in the area in which the device is held. It includes a cavity at the bottom of the.

Yet another object is to provide a circuit card that does not require contact sockets when testing electronic devices.

This object is achieved by a test circuit card comprising a cavity under the contact conductor in the area where the conductor is held.

It is yet another object of the present invention to provide a test method for simply and quickly inspecting an electronic device on a printed circuit card to be tested.

This object is achieved by a method in which the devices are collected and delivered to a test printed circuit card and the device can be held directly on the printed circuit card during testing.

The above and other objects of the present invention and the advantages obtained therefrom become apparent from the following description of the preferred embodiments of the present invention.

2 shows an electronic device 2, preferably surface mounted, comprising a carrier 4 and a circuit card 5 used for testing, ie a so-called printed circuit board (PCB) or mother board 5. A first preferred embodiment of the invention for testing an IC-element is shown. This figure shows only a part of the motherboard 5 in which the device under test (DUT) 2 is arranged. Although the conductors 6 are shown on the motherboard 5 (only a portion of the two conductors are shown), these conductors 6 are generally constructed in a copper pattern on the motherboard. The cavity 9 is arranged in the area of the motherboard 5 in which the element 2 is arranged. The surface of the cavity 9 is constructed according to the device 2 to be tested including the legs. The portion of the conductor 6 to which the legs of the element 2 are to be connected extends on the edge of the cavity 9. A portion of the circuit board material is below the lead 6 to be contacted. In the preferred embodiment, two pressure pads 7 are respectively arranged along each opposing edge of the cavity 9, where each pad is arranged between the bottom of the cavity 9 and the conductor 6.

A cavity 9 is provided in the motherboard 5 so that the conductor 6 is elastic. The pressure pad 7 is made of rubber, plastic, insulating metal, or the like, and can function to control the tension of the conductor 6 and can be removed if desired.

Using the structure of the motherboard 5, the device 2 can be placed directly on the motherboard 5 when the device 2 is tested. When testing the device, the carrier 4 collects the device 2 from a device store (not shown) and moves the device 2 to the motherboard 5, which causes the device to become a cavity 9. The pressure on the upper board 5 is maintained so that the legs of the element 2 are in direct contact with the conductor 6. This is possible because the conductor 6 is elastic.

The carrier 4 is provided with a cavity 11 suitable for the body of the element 2 and a peripheral portion attached to the leg of the element 2 so that the element 2 can be pressed at a constant pressure against the motherboard 5. Include.

The use of the structure of the motherboard 5 when testing the device 2 results in higher measurement accuracy than running the test in a test socket. The problems caused by the test sockets with respect to stray capacitance are avoided and the number of electrical connections is smaller, thereby reducing the number of devices discarded during the test and improving the HF characteristics.

Figure 3 shows another embodiment of the device, in which the carrier 4 is provided with a suction cup 8 which functions to select, move and hold the element. Of course, the carrier 4 may be provided with another type of device that performs the same function, for example a pneumatic device or any type of gripping device.

4 shows a second embodiment of a test assembly wherein the printed circuit board comprises a slot 10 across the cavity 9 at each side of each conductor 6, so that the conductors 6 are individually It has elasticity.

Finally, FIG. 5 shows a carrier 4 held on some printed circuit board 5, where the substrate 5 is provided with a plurality of conductors, which conductors are on both sides of the cavity 9. Is located in. The legs of the device 2 are covered by the carrier 4, but the device 2 and the legs of the device are also shown in this figure. Of course, the substrate 5 may be configured for a circuit having legs on all four sides, and the shape defined by the surface of the cavity 9 is determined only by the shape of the element 2.

The preferred embodiment comprises a large cavity 9 having a surface covering the whole of the device 2 to be tested. However, this cavity can be changed in a number of ways, rather than with respect to different types of devices. For example, individual cavities may be provided for one leg under each conductor or for one leg group under several mutually parallel conductors. In order to be able to have the desired elastic force for each leg of the device, it is a key feature of the present invention that a cavity must be provided under each conductor.

In order to be able to carry out the test procedure quickly and efficiently, the carrier is suitably mounted on a robot, preferably a pick and place robot.

Claims (6)

An electronic device test assembly comprising a printed circuit board (5) and an element carrier (4) for receiving a device (2) and for placing and holding the device with respect to the printed circuit board (5) The printed circuit board 5 has at least one lower portion under the contact conductor 6 so that the contact conductor 6 of the printed circuit board 5 can be elastic in the region where the device 2 is held during the test. An electronic device test assembly comprising a cavity (9) and a printed circuit board and device carrier. The method of claim 1, An electronic device comprising a printed circuit board and a device carrier, characterized in that a pressure pad 7 is provided between the lower part of the cavity 9 and the one or more contact conductors 6 for adjusting the elasticity of the contact conductors. Test assembly. The method of claim 1, In order to make the conductors individually resilient, slots 10 are provided on both sides of each contact conductor 6 across the cavity 9, the former comprising an element carrier and a printed circuit board. Device test assembly. In the printed circuit board 5 for testing electronic devices, The printed circuit board is characterized in that it comprises at least one cavity 9 under the contact conductor 6 such that the contact conductor 6 of the printed circuit board has an elastic force in the region in which the electronic element to be tested is placed. Printed circuit board for testing the device. The method of claim 4, wherein A printed circuit board for testing an electronic device, characterized in that a pressure pad (7) is provided between the bottom of the cavity (9) and at least one contact conductor (6) to adjust the elasticity of the contact conductor. The method of claim 4, wherein To test the electronic device, slots 10 are provided on both sides of each contact conductor 6 across the cavity 9 so that each contact conductor 6 is individually elastic. For printed circuit boards.

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