Patent Application
20050112936
1. Field of the Invention
The present invention relates generally to semi-conductor module test apparatus using so called burn-in boards. More particularly, the present invention is directed to a high current, open/short power connector especially useful with such semiconductor module test and burn-in apparatus. An apparatus provided with the high power, open/short connector of the present invention can easily couple selected devices on the burn-in-board to significantly higher power levels.
2. Background of the Invention
As is well known to the art, integrated circuits modules have a number of signal interface points or pins, herein after referred to as input/output pins, that are used to transfer data, in the form of electrical signals, into or out of the integrated circuits modules. During operation a select number of these pins are used to introduce the necessary functions such as the circuit clocks, test modes, test control data, and etc. to the integrated circuit while other signal interface pins are used to transfer data into and out of the data storage circuits contained in the integrated circuit. These pins are arranged in a particular pattern called a footprint.
One test operation required during the manufacture of such modules is the so called burn-in test performed by placing the modules to be tested on burn-in-boards (BIBs) and powering up the modules while simultaneously heating the burn-in-boards in an oven. Typically the oven are designed to accommodate sixteen to thirty-two burn-in-boards. Each burn-in-board is typically comprised of a board having a plurality of sockets or power planes. Each such socket is adapted to accept therein the footprint of the module to be tested. Each such socket or power plane is thus designed to accommodate a specific type of semiconductor integrated circuit and each burn-in-board is designed such that when it is placed in the burn-in oven each socket or power plane is electrically connected to suitable signal lines and power sources such each module on the burn-in-board can be properly energized. Presently, many semiconductor modules having a particular footprint are tested in these burn-in boards and draw less than 75 amperes of current from the power sources during this burn-in process. Other modules having the same footprint will require a current draw in excess of 75 amperes. Because of the operating characteristics of the burn-in ovens, if a module being tested exceeds the 75 amperes draw they will be considered failures due to over current conditions even though they are not failures. For this reason the higher current drawing modules cannot use the same power planes as the lower current drawing modules and vice versa. Thus, at present, each type of module depending on its current draw requires its own burn-in-board. For this reason the prior art required a multiplicity of burn-in-boards for each board was designed to accommodate a specific module and current draw. Thus a large number of burn-in-boards is required and this multiplicity of boards results in increased capital costs as well as costs due to the need for storage space and maintenance for the additional boards. All of these factors increase the cost of testing the modules. Further there is always a possibility that the wrong power plane could be used resulting in erroneous results which require either retesting or scrapping of the modules so tested. Thus there are compelling economic reasons to be able to easily convert a burn-in-boards power plane current carrying capacity to different levels.
Accordingly the present invention is designed to circumvent these difficulties and does so by providing each burn-in-board with a means for altering the applied current levels of selected ones of the power planes between current desired levels.
The present invention is directed to a novel burn-in-board provided with power planes for testing semiconductor devices, in which current connection means are selectively placed between the power planes for altering the current carrying levels of selected ones of the power planes.
Initially this is achieved by coupling together selected pairs of the power inputs of selected planes such that one of the selected power planes can be coupled with another to provide twice the power level for which the power plan was intended to be operated. In a first embodiment, the present inventors accomplished this by mounting fixed connectors between selected pairs of the power planes. In a second embodiment a unique split connector is mounted between selected pairs of the power planes.
These objects, features and advantages of the present invention will be become further apparent to those skilled in the art from the following detailed description taken in conjunction with the accompanying drawings wherein:
Referring now to
Specifically, current carrying coupling points 17A, 17B, 17C, 17D, 17E, 17F, 17G, and 17H are bolted to respective power input lines 16A, 16b, 16C, 16D, 16E, 16F, 16G, and 16H via a lug 19 affixed to the end of each input line 16A, 16b, 16C, 16D, 16E, 16F, 16G, and 16H by a respective nut 23 and bolt 24 and the ground line coupling points 19A, 19B, 19C, 19D, 19E, 19F, 19G, and 19H are secured to the ground contacts 21 via a lug 27 affixed to the end of each cable 22 and a nut and a bolt.
Such burn-in boards are currently commercially available, from sources such as the Micro-Control Company of Minneapolis, Minn. and sold under the designation HPB-2. Thus their use is well known to the art and further description of such boards is believed to be unnecessary.
In the standard prior art burn-in boards each respective external power cable 16A, 16B, 16C, 16D, 16E, 16F, 16G, and 16H supplies only 75 amps to each respective plane or socket disposed thereon. However, as above discussed, this current level can be inadequate for some of the desired tests or modules and a higher current level was needed to properly test the modules.
The present invention resolves the above described problem by altering the burn in boards so that modules inserted in selected ones of the power planes can be operated above 75 amps but less than 150 amps. The present invention does this by selectively altering selected connections on the burn-in boards to permit selected one of the power planes to operate modules placed thereon to operate a power levels twice that normally permitted.
The first embodiment of the present invention is especially shown in
Thus as shown in
When the cables are provided with such connectors modules mounted on planes 11A, 11C, 11F and 11H can be operated up to supply 150 amps to modules inserted therein. If the modules inserted in planes 11A, 11C, 11F and 11H are expected to operate so as to draw up to 150 amps, the remaining planes 11B, 11D, 11E and 11G should not be used. In this way one half of the planes on a burn-in-board can be used to test modules at current levels up to to least twice that at for which the board was initially designed.
Although it is preferred that both sets of planes, i.e., planes 11A, 11C, 11F and 11H and planes 11B, 11D, 11E and 11G, not be loaded with modules simultaneously, it should be noted that in some instances both sets of planes, i.e., planes 11A, 11C, 11F and 11H and planes 11B, 11D, 11E and 11G, can have modules simultaneously inserted therein. In such a case it is necessary that the combined current draw of the modules inserted in each pair of coupled planes not exceed 150 Amps. This can be the case even when one of the paired modules exceeds 75 amps. For example if plane 11A has a module therein that draws 85 amps and its coupled plane 11B has a module therein that draws less than 65 amps both modules can be simultaneously treated on the same burn-in-board.
However the above process of converting such a burn-in-board to such coupled pairing as above described, although operable, required a time consuming install operation and once converted the burn-in-board could not be returned to its previous condition unless the install operation was reversed and the fixed connectors were removed. Since the conversion of just one eight plane burn-in board from a 75 ampere operation to a 150 ampere operation using the above fixed connectors required up to fifteen minutes, the conversion of sufficient boards for the smaller 16 board ovens requires three hours and any reversal to 75 amperes from 150 amperes required the same amount of time. For a larger thirty-two board oven such conversions requires twice as much time. Thus the use of such fixed connectors, although operable, required excessive conversion times during which both the burn-in-boards and the ovens remained inoperable. Thus although some economic advantage was realized it was marginal for the labor costs required for the conversions was significant.
Although the insertion of such fixed connectors and solved the problem, this process required time consuming install and/or removal operations that minimized the economic advantage realized by the conversion.
The present inventors persisted however and found that the desirable result of converting the burn-in-board to dual current uses could be inexpensively realized and the conversion time reduced from between twelve and fifteen minutes per board to less than one minute per board. This increased time advantage was achieved through the use of a plurality of unique split connectors of the second embodiment of the present invention which once installed need never be removed yet but can be swiftly altered thereby permitting selected ones of the power planes to quickly and easily be joined or separated to alter the applied current levels from either 75 amperes to 150 amperes or from 150 amperes back to 75 amperes.
Accordingly the inventors achieved such a result by creating and using a high power, open/short connector as shown in
When the separate halves of each high power, open/short connector, of the present invention, are so mounted on the spacer 35 a coupling device such as a nut 40 can be placed on the rejoined stud 33 and the connector can be mounted between selected pairs of the coupling plates 17. Once mounted between the selected pairs of coupling plates the nut 40 can be removed and each half of the connection is again electrically isolated from the other half. Because the two halves of the open short connector are so isolated from each other, each plane 11A, 11B, 11C, 11d, 11E, 11F, 11G, and 11H remains operable at 75 amperes and modules can be placed on each plane and be tested up to 75 amperes. It should be understood that the width of the saw used to cut the base 30 and stud 33 in half must be such that when the spacer 35 is inserted there between the thickness and insulating properties must be sufficient to prevent the applied voltages and currents. However, when 150 ampere devices are to be tested, the coupling device, e.g., nut 40, having internal threads mating to the external treads on the rejoined stud 33, is threaded onto each split, insulated and rejoined stud, the insulation between the halves is bridged by the nut threaded thereon and the halves become electrically interconnected electrically interconnecting the adjacent cables bridged by the open/short connector of the present invention. When so connected or ganged either one of the now connected planes can provide up to 150 amps to a module inserted in one of the planes. Thus, as shown in
When the above described cables are so interconnected by the placing of the nuts 40A, 40B 40C and 40D on the appropriate rejoined studs, modules mounted on planes 11A, 11C, 11F and 11H can be operated up to 150 amperes. In this way one half of the planes on a burn-in-board can be used to test modules at current levels higher than normal i.e., in the present example higher than 75 amps. To reset the each of the ganged or combined pairs of planes to 75 ampere operation all that is required is to remove each respective coupling nut 40 from each of the high power, open/short connectors on which they were placed. Such removal takes less than one minute per burn-in-board. Thus once the high power, open/short connector of the present invention is initially installed on the burn-in-board the time need to switch the planes between different current levels is minimized resulting in a significant labor saving.
However, as discussed above, when the planes are ganged or combined as above described they can all be populated with modules that are expected to draw less 150 amps in combination. In such a case all the planes 11A, 11B, 11C, 11D, 11E, 11F, 11G and 11H can be used.
Although it is preferred to form the openings 31 and 32 offset to one side of the connector in order to identify the right and left hand sides of the open/short connector of the present invention other means to so identify the separate halves. Further by assuring the thread created on each stud 33 is always started on each stud at the same point and cut in the same position by a saw of the same thickness, the left side of the open/short connector, of the present invention, will always mate with the right side of any open/short connector of the present invention and means that exact matching of left and right sides is not necessary and assures that any right hand side 30A can be accurately joined to any left hand side 30B by any nut 40.
It has also been determined that if the nuts 40 is provided with a slight amount of thread relief 41 at the lower edge of the nut better electrical contact is assured between the nut 40 and right and left stud portions 30A and 30B. Such thread relief is realized by under cutting or removing the thread at the lower edge of the nut as shown in
It should be further understood that the stud portions need not be circular, in cros section or threaded but can, for example, be tapered or otherwise shaped such that a suitable coupling device can be placed thereon to create an electrical short between the stud portions 30A and 30B the stud need not be threaded but can, for example, be shaped such that a suitable coupling device can be used to electrically short the rejoined stud portions.
Other alternate features and solutions will now become obvious to one skilled in the art after review of the present invention.
This completes the description of the preferred embodiment of the invention. Since changes may be made in the above construction without departing from the scope of the invention described herein, it is intended that all the matter contained in the above description or shown in the accompanying drawings shall be interpreted in as illustrative and not in a limiting sense. Thus other alternatives and modifications will now become apparent to those skilled in the art without departing from the spirit and scope of the invention as set forth in the following claims.
