RELATED APPLICATIONSThis is a continuation of application Ser. No. 09/946,552 filed Sept. 6, 2001, which is a divisional of application Ser. No. 08/474,489 filed Jun. 7, 1995, now U.S. Pat. No. 6,288,561, which is a continuation-in-part of application Ser. No. 08/055,439 filed Apr. 30, 1993, now U.S. Pat. No. 5,451,489, which is a division of application Ser. No. 07/775,324 filed Oct. 11, 1991, now U.S. Pat. No. 5,225,771, which is a division of application Ser. No. 07/482,135 filed Feb. 16, 1990, now U.S. Pat. No. 5,103,557, which is a continuation-in-part of application Ser. No. 07/194,596 filed May 16, 1988, now U.S. Pat. No. 4,924,589; and is also a continuation-in-part of application Ser. No. 08/315,905 filed Sept. 30, 1994, now U.S. Pat. No. 5,869,354 which is a division of application Ser. No. 07/865,412 filed Apr. 8, 1992, now U.S. Pat. No. 5,354,695 and is also a continuation-in-part of application Ser. No. 08/217,410, filed Mar. 24, 1994, now U.S. Pat. No. 5,453,404, which is a continuation of application Ser. No. 07/960,588, filed Oct. 13, 1992, now U.S. Pat. No. 5,323,035.[0001]
BACKGROUND OF THE INVENTION1. Field of the Invention[0002]
The present invention relates to test equipment and more particularly to equipment for probing, testing, burn-in, repairing, programming and binning of integrated circuits.[0003]
2. Description of the Related Art[0004]
In conventional semiconductor equipment technologies, separate pieces of equipment are required to test, burn-in, repair, program and bin integrated circuits (ICs). Integrated circuits that are in wafer form are tested or screened for packaging using a tungsten needle probe card, wafer positioning equipment called a prober and automatic test equipment (ATE) which supplies test signals to the probe card and determines the validity of any output signals. A probe card is a connector that provides a mechanical means for making a temporary contact to the contact pads on an IC for the purpose of testing the IC. The probe card may contact only a single die, but it may typically contact as many as eight or more dice if the dice consist of memory ICs.. A die typically consists of one IC; however, it may include a plurality of ICs. Conventional probe cards do not provide the capability of contacting all the dice on a wafer at once.[0005]
An IC is typically burned-in and speed-graded prior to its use or sale. Burn-in of circuit devices requires many hours of testing the devices under stressing temperature and electrical conditions. An IC is burned-in to lower the possibility that it will fail after it is inserted into an electronic assembly such as a Multi-Chip Module (MCM) or printed circuit board (PCB) of other ICs. Burn-in of an IC is performed typically after the IC is in packaged form. Burn-in fixtures for processing a die before packaging, so called bare die burn-in, are beginning to become available. Whether an IC is in packaged form or in die form, a separate piece of equipment is used to burn-in an IC. After an IC has been burned-in, it is speed-graded or binned using automatic test equipment. Binning is a process that sorts ICs according to their performance characteristics.[0006]
When an IC is in wafer form, and it contains shorts that disrupt the functionality of the IC, it may be repaired by removing portions of a deposited layer (e.g., a polysilicon layer or an aluminum metal layer). A laser cutting machine is typically used to perform the circuit repair. If an IC is a memory circuit array, yet another machine is required to program the memory circuit array by fusing or anti-fusing circuits within the memory circuit array. Subsequent to repair of an IC, the IC must be tested again.[0007]
It would be advantageous, and is therefore an object of the present invention to provide a single piece of equipment that can perform all of the functions mentioned above that are previously done by separate pieces of equipment to reduce capital equipment expense and the number of steps required for IC burn-in, testing, repairing and/or programming.[0008]
SUMMARY OF THE INVENTIONThe present invention provides a single gas tight system that can perform multi-functions including reducing the thickness of oxides on contact pads and probing, testing, burn in, repairing, programming, marking and binning of integrated circuits. A system according to one embodiment of the present invention includes: (a) a gas tight chamber having (1) one or a plurality of modules each having a holding fixture, a wafer, a probing device, other processing device such as a die inking or repairing device, an electronic circuit board, and a thermal control device, (2) a gas source for supplying non-oxidizing gases such as nitrogen and hydrogen into the chamber, (3) a handler for moving the wafers and the probing or other processing devices, and (b) a computer coupled to the chamber for controlling and communicating with the handler, the temperature control devices, the holding fixtures, the probing and other processing devices.[0009]
A holding fixture holds a wafer having integrated circuits and aligns the wafer to a probing device or other processing device. An integrated circuit has a plurality of conductive contact portions, typically referred to as contact, I/O or bond pads, that are couplable to probe points of the probing device. A temperature control device is used to heat the wafer during an oxide reduction process. When hydrogen is present in the chamber and the wafer is heated, the oxides on the wafer combine with hydrogen to form water vapor, thus reducing the thickness of the oxides. The temperature control device may also be used to heat or cool the wafer during burn-in of the wafer.[0010]
A probing device can have multiple probe points or a single probe point. the probing device can be a full-wafer probing device having active switching logic circuits to allow controlled access to each of the integrated circuits on a after, and optionally, generate some or all of the test signals required for testing the die.[0011]
The computer can generate a computer database with the various status information for every circuit processed by wafer and on-wafer site location. The database can provide timely performance distribution statistics and physical distribution statistics to the circuit manufacturing engineers or process engineers to allow adjustments to be made to the manufacturing process. By using the database, processing steps that are slowly going out of specification and affecting product quality can be corrected. Thus, the capability of near-real time adjustments to the manufacturing process will allow savings by reducing the number of products that do not satisfy specifications.[0012]
The present invention allows a single semiconductor test and circuit configuration machine to perform any or all of the following: (a) reducing the thickness of oxides on contact pads of integrated circuits on a wafer by supplying a first non-oxidizing gas such as nitrogen into the chamber, heating the contact pads, and supplying a second non-oxidizing gas such as hydrogen into the chamber so that the oxides can combine with hydrogen to form water vapor, (b) probing the contact pads using a probing device, (c) testing the functionality of the integrated circuits, (d) burning-in the integrated circuits for a predetermined period of time over a predetermined range of temperature with predetermined temperature rate of change and electrical conditions, (e) generating test vector data and analyzing data collected from the integrated circuits, (f) repairing the integrated circuits, (g) programming the integrated circuits by fusing or antifusing specific circuits within the integrated circuits, (h) marking or printing on the wafer, (i) binning the integrated circuits according to their performance characteristics, and (j) collection of a database for immediate feedback to the manufacturing process.[0013]
BRIEF DESCRIPTION OF THE DRAWINGSThe objects, features and advantage of the present invention will be apparent from the following detailed description in which:[0014]
FIG. 1 is a multi-functional semiconductor test and circuit configuration system according to the present invention.[0015]
FIG. 2 is one of the modules shown in FIG. 1.[0016]
FIG. 3 is a wafer having a plurality of integrated circuits.[0017]
FIG. 4 is a flow chart illustrating the steps of reducing the thickness of oxide films on the contact pads of the integrated circuits and the steps of testing, burning-in, configuring and binning the integrated circuits according to the present invention.[0018]
FIG. 5 is a detailed block diagram of the computer shown in FIG. 1 according to one embodiment of the present invention.[0019]
DETAILED DESCRIPTION OF THE INVENTIONThe present invention provides methods and apparatus for performing testing, burn-in, repairing, programming, and binning of integrated circuits in a closed environment using a single piece of equipment. In the following detailed description, numerous specific details are set forth such as particular hardware configurations and a flow chart to provide a thorough understanding of the present invention. It will be appreciated, however, by one having ordinary skill in the art that the present invention may be practiced without such specific details. In other instances, well-known structures and methods are not described to avoid obscuring the present invention unnecessarily.[0020]
Now referring to FIG. 1, a semiconductor test and[0021]circuit configuration system5, which is a cluster tool, is presented according to one embodiment of the present invention.System5 includes achamber10 and acomputer30.Chamber10 includes a plurality of modules14a-14efor processing wafers, ahandler12 for moving wafers and probing devices, and awafer cassette22 for holding a plurality of wafers.
It will be appreciated that the present invention may be used to process other substrates even though the specific details set forth the processing of a semiconductor wafer. Other substrates, circuit substrate types, or substrate assemblies that the present invention can process are Multi-Chip Module and flat panel display substrates which may be made from various materials such as AlN, SiC, quartz, glass or diamond.[0022]
[0023]Chamber10 shown in FIG. 1 includes a plurality of modules. Although five modules are shown in FIG. 1,chamber10 may include more modules or fewer modules. Since a wafer cassette usually holds twenty-five wafers, a chamber can be made to include twenty-five modules for processing twenty-five wafers simultaneously. It should be noted that each of the modules may perform the same function (or functions). For instance, all of the modules may perform functional testing, burn-in and repairing of ICs in the same sequence and at the same time. On the other hand, the modules may perform different functions. For example, whilemodule14aperforms a functional test,module14bmay perform programming of ICs. Moreover, the modules can also perform each function independently and in any order, such as performing a test function without burn-in processing or performing a test function both before and after other processing steps.
[0024]Chamber10 may be a closed system or an open system. Whenchamber10 is a closed system,chamber10 is a gas tight system, not allowing gas molecules to move across thechamber boundary24. The pressure insidechamber10 may be more than, at, or less than atmospheric pressure. In one embodiment,chamber10 includes agas source20 whereingas source20 can introduce non-oxidizing gases such as nitrogen and hydrogen intochamber10. As will be described later, having a non-oxidizing environment is beneficial in forming good contacts between probing devices and the contact pads of integrated circuits.
It will be appreciated that in another embodiment, each module in[0025]chamber10 can be in a separate gas-tight closed environment. In such a case, each module would have doors to close off and isolate the atmosphere and temperature of the module and each module could contain a separate gas source. For example, one module can contain nitrogen and hydrogen to reduce the thickness of metal oxide films, while another module may contain only nitrogen to perform another function such as a functionality test on an IC.
[0026]Handler12 in FIG. 1 can be a robotic system that moves wafers betweenwafer cassette22 and the holding fixtures or between the holding fixtures and changes the probing devices when the type of wafer is changed.Handler12 has the capability to move multiple wafers simultaneously. It should be noted that a module can be manually loaded with a wafer instead of using thehandler12.
FIG. 2 presents a module[0027]14a.sup.1. Module14a.sup.1 is identical tomodule14aof FIG. 1 except that module14a.sup.1 contains agas source50. Since modules14a-14eare identical, no separate description is provided for modules14a-14e. Module14a.sup.1 in FIG. 2 includes a probingdevice42 having probe points44 for probing contact pads onwafer40 andcircuitry50 which is coupled to anelectronic circuit board18a. A holdingfixture16ahas a plurality of vacuum holes for pulling downwafer40 onto holdingfixture16aand athermal control device48 for controlling the temperature of thesubstrate40. Module14a.sup.1 also includes agas source50 for introducing non-oxidizing gases into module14a.sup.1.
[0028]Wafer40 includes a plurality of integrated circuits (ICs)64a-64las shown in FIG. 3. Each IC includes a plurality of conductive contact portions such as contact pads66 (not all are shown in FIG. 3). Conductive contact portions are not limited to contact pads, and they may include various types of metal portions that are exposed on a wafer. Conductive contact portions are usually made of aluminum. However, they may be made from various other types of metal. ICs onwafer40 may be of different sizes, and the contact pads may be also of different sizes.Wafer40 in FIG. 2 may represent a full wafer as shown in FIG. 3 or a partial wafer. In the preferred embodiment,wafer40 is a whole wafer.Wafer40 may be a silicon wafer, GaAs wafer, or any other semiconductor wafer. It should be noted thatwafer40 may include only simple circuits wherein the circuits may be passive circuits, active circuits or metal lines.
Continuing to refer to FIG. 2, probing[0029]device42 may contain a single probe point, a small number of probe points (5-40) or a large number of probe points (approximately 100,000 to 500,000 or more). In the preferred embodiment, probingdevice42 is a full-wafer probing device. U.S. Pat. Nos. 5,103,557 and 5,323,035 issued to this inventor disclose how a full-wafer probing device can be fabricated. A full-wafer probing device has the capability to contact all of the contact pads on a wafer at once. The number of probe contact points that may be required in such wafer probing device can exceed 100,000 points. As shown in U.S. Pat. No. 5,103,557, a full-wafer probing device can also include a circuitry that allows each die of a wafer to be individually tested and/or isolated if it is faulty. This is shown ascircuitry50 in FIG. 2. Also, U.S. Pat. No. 5,354,695 discloses a fabrication process for making an intelligent probing device through the use of membrane circuits.IC circuitry50 also provides the means to reduce the number of electronic signal connections to and from the probing device to a number that is approximately the same as the number of signals associated with each die and not the number of connections equal the number of dice on a wafer times the signals per die. WhenIC circuitry50 incorporates active circuit switching logic, it provides a controlled access to each die on a wafer.
[0030]IC circuitry50 of probingdevice42 is connected toelectronic circuit board18awhich is coupled tocomputer30 in FIG. 1.Electronic circuit board18ais used as a common mechanical and an electrical interface between probingdevice42 andcomputer30 so that probingdevice42 can receive control signals fromcomputer30 and send data signals tocomputer30. In another embodiment,chamber10 of FIG. 1 can contain one electronic circuit board for all the probing devices instead of having one electronic circuit board for each probing device as shown in FIG. 2.
Probing[0031]device42 has probe points44 andIC circuitry50 that are specific for a wafer being tested. A probing device can be changed with another byhandler12 in FIG. 1 when the type of wafer is changed. Although probingdevice42 can incorporate active device switching circuitry such as transistors on the electronic circuit boards, probingdevice42 could also only incorporate passive circuit elements such as resistors, inductors, and capacitors. In the latter embodiment, there would be a reduction in the complexity of fabrication of probing devices but an increase in the number of I/O interconnections from probing devices to the supporting control circuitry. With the former embodiment of the probing devices, higher at-speed tests can be performed as there is no concern for degradation of signal integrity due to the constraints of path propagation and signal bandwidth. The incorporation of active device switching circuitry into probing devices would create intelligent and programmable probing devices.
Still continuing to refer to FIG. 2, holding[0032]fixture16ais used to holdwafer40 and alignwafer40 to probingdevice42. Holdingfixture16aincludes avacuum source46 having a plurality of vacuum holes to holdwafer40 firmly against holdingfixture16aandtemperature control device48 for heating orcooling wafer40. Holdingfixture16ais controlled bycomputer30 in FIG. 1. Whenwafer40 is placed on holdingfixture16a,computer30 sends control signals to vacuumsource46 to apply vacuum to pull downwafer40 against holdingfixture16a, and at the completion of testing, repairing or programming of the ICs onwafer40,vacuum source46 may be turned off so thatwafer40 can be released from holdingfixture16a.
[0033]Temperature control device48 is also controlled bycomputer30. To burningwafer40 or to remove oxide from the contact pads ofwafer40,computer30 sends control signals totemperature control device48 to control the temperature of thewafer40.Computer30 controls and monitors the temperature ofwafer40 so that it is changed to predetermined temperatures for a predetermined period of time. The rate at which the temperature ofwafer40 is changed can also be controlled bycomputer30 through the use oftemperature control device48. In FIG. 2,temperature control device48 is embedded in holdingfixture16ato control the temperature ofwafer40. However,wafer40 can be heated by radiation or by some type of ion beams. Focused ion beams can be used to heat only a portion ofwafer40 or only a specific contact pad onwafer40.Temperature control device48 can also be used to reduce the temperature ofwafer40 for cases where the operation of all the circuits on a substrate may have a combined thermal energy generation exceeding the desired burn-in temperature or for situations where simulation of a low temperature environment is desired. For temperatures lower than 25 degree C., where moisture condensation can result on substrates, the use of a gas tight system as described above would be preferred such that most of the water content is removed. The common methods and apparatus used to control the temperature of a substrate is well-known in the art and thus is not discussed further.Computer30 also controls the movement of holdingfixture16aso that it can be aligned to probingdevice42. The detailed description of alignment ofwafer40 to probingdevice42 is disclosed in U.S. Pat. Nos. 5,103,557 and 5,354,695, describing optical and electronic sensors, respectively. It should be noted that instead of moving holdingfixture16a, probingdevice42 can be moved to align probingdevice42 towafer40. Although, in the preferred embodiment,computer30 controls turning on and offvacuum source46, the movement of holdingfixture16aand the temperature oftemperature control device48, such functions can be performed manually.
During functional circuit testing,[0034]computer30 sends control signals to probepoints44 of probingdevice42 throughelectronic circuit board18aandIC circuitry50. ICs onwafer40 generate data signals in response to the control signals, and the data signals are sent back tocomputer30 so thatcomputer30 can analyze the data signals and determine the functionality of each IC onwafer40.
During burn-in,[0035]computer30 sends control signals to heat orcool wafer40 to specific temperatures for a predetermined period of time and electrical signals to probepoints44 of probingdevice42 so that the ICs onwafer40 can be tested while they are stressed under certain temperature and electrical conditions. The ICs onwafer40 generate data signals which are sent tocomputer30 to analyze and determine which ICs pass the burn-in test.
After a functional test or a burn-in test,[0036]computer30 analyzes the data obtained from the ICs onwafer40 and provides new control signals to probepoints44 either to repair the ICs onwafer40 and/or to program the ICs by fusing or anti-fusing circuits within the ICs as is done with memory circuits. For example, to repair a circuit,computer30 can provide control signals to probingdevice42 so that high voltage or current can be provided between the appropriate probe points to open up a conducting path or conducting paths. This repairing scheme is used in many areas including, but not limited to, removing shorts created by manufacturing defects, disabling or enabling a portion of a circuit, isolating a portion of a circuit, and attaching a spare or redundant sub-circuit replacing a sub-circuit that has been detached from a main circuit. To program a memory circuit array,computer30 sends control signals based on the data collected from each IC onwafer40.IC circuitry50 of probingdevice42 configures the probe points to enable direct programming of fuses or anti-fuses through the probe points. A Read Only memory circuit array is typically a programmable read only memory (PROM) or a programmable logic array (PLA).
The present invention allows a single semiconductor test and circuit configuration system to perform any or all of the following functions: (a) reducing the thickness of oxide films, (b) performing functionality tests on integrated circuits, (c) performing burn-in tests on ICs, (d) repairing the circuits, (e) programming fuses or anti-fuses, (f) binning the ICs that have been tested, and (g) collection of a database for immediate feedback to the manufacturing process.[0037]
First, the present invention can be used to reduce the thickness of oxide films on contact pads of ICs. A typical IC contact pad is made of aluminum, and it naturally forms a 25 .ANG. to 40 .ANG. oxide film on the surface of the contact pad soon after the contact pad is exposed to oxygen. This oxide film optionally can be penetrated by a piercing probe point as described in U.S. Pat. No. 5,323,035 in order to achieve a low resistance contact between a probing point and the contact pad. In operation, when a wafer is moved from[0038]wafer cassette22 onto a holdingfixture16ainmodule14a, a non-oxidizing gas such as nitrogen is introduced toflood chamber10 and to purge the chamber of oxygen. Then the temperature of the wafer is changed to a specific temperature appropriate for the metal of the contact pads, and a few percent by volume of hydrogen is introduced over the surface of the wafer so that the oxide films can be converted into water vapor when they are combined with hydrogen. The oxide films may be completely removed from the contact pads, or at least the thickness of the oxide films will be reduced by this process. By maintaining a nitrogen environment inchamber10, no further oxide is formed on the surface of the metal contact pads, thus providing better contacts between the contact pads and the probing points. Nitrogen is a preferred non-oxidizing gas, and there may be other gases such as argon that may be used inchamber10.
Second, the present invention can be used for functional testing of integrated circuits. After the oxide films on the contact pads have been removed or reduced in thickness, or subsequently are to be pierced, the probing points of the probing device come into contact with the contact pads on the wafer.[0039]Computer30 controls the functional testing of the ICs on the wafer.Computer30 supplies the control signals, receives data signals back from the probing points, and analyzes the data to determine which ICs are functional on the wafer.
Third, the present invention can also perform burn-in of integrated circuits. During burn-in, the integrated circuits on the wafers are tested for a predetermined period of time over a range of predetermined temperature and electrical conditions to produce burn-in data which is transmitted to[0040]computer30 for analysis.
Fourth, after obtaining data from the ICs,[0041]computer30 can analyze the data and bin or speed-grade the integrated circuits according to their individually determined maximum performance.
Fifth, the present invention can also be used to repair the circuits.[0042]Computer30 can supply appropriate control signals to the probe points of the probing device so that appropriate voltage or current can be applied between the probe points to electrically isolate defective portion of an IC or electrically connect spare circuit portions of an IC with the use of fuse and anti-fuse circuit devices. Under appropriate circumstance, arbitrary shorts in a circuit may be opened if probe points are positioned anticipating such short failure condition.
Sixth, the present invention provides a means for programming PROM, EEPROM or PLA circuits. The programming done is typically to pre-set or store binary values in non-volatile memories such as PROM or EEPROM. Small non-volatile memories in microprocessor circuits may also be programmed with serial numbers or version numbers, and configuration or operational parameters that have been generated by test/burn-in processing. Logic products with non-volatile memory may also be programmed such as PLA's or FPLA's. The present invention can also verify and test the capabilities of the circuits after it has been programmed. Thus, if the wafers in[0043]chamber10 contain memory circuits,computer30 can supply control signals to the probe points so that the probe points can apply appropriate charges to the circuits within the memory circuits. The ICs can be re-tested for their functionality or burned-in after the circuits are repaired and/or programmed. Also, the binning process can be performed after a functionality test, burn-in or circuit configuration.
Seventh, the present invention provides a means for generating a computer database with the various status information for every circuit processed. This database can be used in subsequent processing steps by the present invention, such as in the repairing or programming steps. One important aspect of the database is that it can provide timely performance distribution statistics and physical distribution statistics to the circuit manufacturing engineers or process engineers. Presently, such information is only partially available after packaging is completed, typically several weeks later. The present invention would make the availability of this information timely enough to allow adjustments to be made to the manufacturing process so that processing steps that are slowly going out of specification and affecting product quality can be corrected. The capability of near-real time adjustments to the manufacturing process will allow savings by reducing the number of products that do not satisfy specifications.[0044]
FIG. 4 presents a flow chart illustrating a typical process flow of the present invention. At[0045]step82, a wafer cassette having a plurality of wafers is inserted into the chamber. Atstep84, the chamber is closed. Atstep86, the wafers are loaded into the individualmodules using handler12 in FIG. 1. Atstep88, a non-oxidizing gas such as nitrogen is introduced intochamber10 to flood the chamber and purge the chamber of oxygen and moisture. Atstep90, the wafers are heated. Atstep92, a few percent by volume of hydrogen is introduced over the surfaces of the wafers. Atstep94, the oxide films on the contact pads of the wafers are removed or reduced in thickness when the oxides combine with hydrogen. Atstep96, hydrogen is stopped from flowing intochamber10, but nitrogen continues to be supplied tochamber10 to maintain a nitrogen environment inchamber10. Atstep98, the ICs are probed for a functionality test and/or electrical burn-in. Atstep100, circuit configuration can be performed to either repair the circuits and/or to program the circuits if the circuits are non-volatile memory circuits. Atstep102, the ICs on the wafers can be re-tested for their functionality. Atstep104,computer30 in FIG. 1 can analyze the data obtained from the ICs and bin the ICs according to their performance characteristics. Atstep106, the wafers are unloaded from the holding fixtures and placed into the wafer cassette. Atstep108, the chamber is opened to take the wafer cassette out from the chamber.
FIG. 5 shows a computer system that may be utilized as[0046]computer30 in FIG. 1 in accordance with the present invention. Acomputer host1000 includes amemory1008 and acentral processor1002.Memory1008 andcentral processor1002 are those typically found in most general purpose computers and almost all special purpose computers. In fact, these devices contained withincomputer host1000 are intended to be representative of the broad category of data processors and memory. Many commercially available computers having different capabilities may be utilized in the present invention. It will be appreciated that althoughcomputer30 may include various other components described below, it may only needcomputer host1000 to control the elements inchamber10.
A[0047]system bus1016 is provided for communicating information to and fromcomputer host1000 and the electronics inchamber10 to allow control and the transfer of data.System bus1016 can also be used to connectcomputer host1000 to other components. For example, adisplay device1010 utilized with the computer system of the present invention may be a liquid crystal device, cathode ray tube or other display device suitable for creating graphic images and/or alphanumeric characters recognizable to a user. The computer system may also include analphanumeric input device1012 including alphanumeric and function keys coupled tobus1016 for communicating information and command selections tocentral processor1002, and acursor control device1018 coupled tobus1016 for communicating user input information and command selections tocentral processor1002 based on a user's hand movement.Cursor control device1018 allows the user to dynamically signal the two-dimensional movement of the visual symbol (or cursor) on a display screen ofdisplay device1010. Many implementations ofcursor control device1018 are known in the art, including a track ball, mouse, pen, joystick or special keys on thealphanumeric input device1012, all capable of signaling movement in a given direction or manner of displacement.
The computer system of FIG. 5 also includes an[0048]interface device1019 coupled tobus1016 for communicating information to and from the computer system.Interface device1019 may be coupled to a microphone, a speaker, a network system, other memory devices, other computers, etc. Also available for interface with the computer system of the present invention is adata storage device1017 such as a magnetic disk or optical disk drive, which may be communicatively coupled withbus1016, for storing data and instructions. The computer system of FIG. 5 may also include a printer for outputting data.
Although functional testing is the typical testing capability of the preferred environment, parametric testing can also be done for circuit characterization. The software that controls the mechanics of the present invention, the data preparation for testing, test processing, and test result analyzing complements the circuitry contained in the probing devices contained in the modules.[0049]
While the present invention has been particularly described with reference to the various figures, it should be understood that the figures are for illustration only and should not be taken as limiting the scope of the invention. Many changes and modifications may be made to the invention, by one having ordinary skill in the art, without departing from the spirit and scope of the invention.[0050]