Process and system for temperature control and in-line testing of electronic, electromechanical and mechanical modules

A process and system exists for temperature control and testing of modules, such as printed circuit boards, with fitted electronic, electromechanical and mechanical components or individual components, wherein the modules are subjected, following assembly in a soldering process and when the solder joints are still in a semi-molten state, to one or more test phases at high and low temperature, in order to detect defects at an early stage and to take immediate corrective measures when errors occur. To this end, in a first test phase the modules are cooled, as they emerge from the soldering process, to a temperature ranging from 40.degree. to 125.degree. C. and tested in a first test phase. Thereafter, in a second test phase the modules are cooled to a temperature ranging from -40.degree. to 10.degree. C. and tested. In the respective test phase the modules are subjected to a component and/or function test in order to determine defective modules. Modules that are found to be faultless are then fed to a dispenser, whereas defective modules are sorted out from the path to the dispenser and an error message is sent. To improve the error inspection, the modules are provided with a digital code that can be read prior to the respective test phase, so that management of defective and faultless modules is possible with digital computers.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a process and system for temperature control and 
in-line testing of electronic, electromechanical or mechanical modules 
with the components fitted as semi-finished products, in particular 
printed circuit boards, which leave in succession a soldering station and, 
following temperature control in a test phase, are connected electrically 
or optically to at least one electric or optic testing device by means of 
an adapter unit and are tested by means of the testing device. 
2. Discussion of Background 
A system for handling and testing printed circuit boards with the electric 
or electronic components fitted is known from U.S. Pat. No. 4,818,933, 
where the printed circuit boards are tested in devices with respect to the 
correct positioning and orientation of the components fitted and with 
respect to the function prior to their final installation. The system 
exhibits a supporting frame, which contains at least one adapter plate for 
contacting printed circuit board contacts, and orientation devices and 
locking devices and conveyor for feeding in and carrying away the printed 
circuit boards to be tested. The essential feature in this system is that, 
during the testing process, the next printed circuit board can already be 
fed in and stopped. 
Furthermore, an integrated printed circuit board testing system is 
described in the U.S. Pat. No. 5,055,779, where the conversion of a 
conventional vacuum test system into a mechanical test system is 
described. The use of such test systems for testing printed circuit boards 
at high temperatures or low temperatures has been demonstrated to be a 
problem, since the appropriate test electronics is attached directly to 
the adapter in order to scan the test points on the pc boards, and an 
ambient temperature of 100.degree. C., as required for a high temperature 
test for printed circuit boards, would also increase, for example, the 
operating temperature of the test equipment and thus possibly impair its 
proper operation. 
A test console with a chamber, in which test pc boards for electronic 
components are arranged, is known from the DE-GM 83 04 116. In the test 
chamber it is determined whether or not the test pc board fails under the 
specified test conditions, such as temperature; if special sealing 
measures for the test chambers are used, a plurality of electric contacts 
between the selected pc board of the test device and the test pc boards is 
to be produced in a minimum of space within the console. 
Furthermore, test equipment including a furnace chamber for testing 
electric components arranged on printed circuit boards is known from the 
DE-PS 37 21 653, wherein the walls, floor or cover have one slot or 
multiple slots with temperature resistant sealing lips that are attached 
to both sides of the longitudinal sides of the slot and through which 
parts of the supporting plates can be pushed. The sealing lips are formed 
by two sluice-shaped sealing profiles of a cross section that is, for 
example, U-shaped, where the profiles rest flat in the center of the slot. 
Furthermore, a device for testing single electronic components, such as 
integrated circuits, is known from U.S. Pat. No. 4,607,220, wherein 
the-test conditions are conducted in a wide temperature range of 
-65.degree. to +150.degree. C., for example. 
The problem with the known temperature control and test equipment has 
proven to be the batch loading of the furnaces or consoles or test 
equipment, so that a function test is not possible between the production 
steps or temperature control phases; and the final test of the modules 
cannot take place until said modules are finished; i.e., complete assembly 
with their external connecting configuration. 
SUMMARY OF THE INVENTION 
Accordingly, the objects of this invention are to provide a novel method 
and system for temperature control and testing of electronic, 
electromechanical or mechanical modules, with component elements fitted as 
semi-finished products, in particular printed circuit boards, wherein the 
printed circuit boards are subjected to at least one test phase at high 
and/or at low temperature, for example, by means of an in-circuit tester 
(ICT) or a functional tester, in a range of -50.degree. to 200.degree. C., 
immediately following a soldering process as the printed circuit boards 
emerge from the soldering station, and wherein determined module defects 
immediately trigger correction measures, thereby to eliminate quickly 
systemic errors in the preceding production steps so that large numbers of 
defective modules can be avoided and so that the supplied energy shall be 
optimally utilized. In one embodiment, the number of defective printed 
circuit boards in a defined time interval is determined, and when the 
number exceeds a set number, temperature testing is suspended and 
corrective measures are taken in the processing stations upstream of the 
testing station, such as in a printer, a pick-and-place machine and a 
soldering station. In this way the present invention avoids producing of 
additional defective printed circuit boards until the source of the defect 
is located and corrected. 
Furthermore, the present invention permits the use of computer directed 
process controlled production facilities, so that extensive automation of 
the production and temperature control/test process of the electronic 
printed circuit boards can be obtained. Moreover, owing to the thermal 
stresses conducted between the individual production steps, the production 
steps, preceding the respective function test are checked for their 
parameters that are effective for the reliability with a subsequent 
function test, so that a fast correction of the production parameters and 
thus a lower failure rate of semi-finished products can be obtained. 
One important advantage of the invention lies in the fact that owing to the 
fast recognition of defective production steps, a continuous optimization 
of the individual components or the entire production sequence is 
possible, thus enabling an immediate sorting out of defective modules with 
subsequent repair. In addition it has proven to be advantageous to control 
the known errors or too high error tolerances for optimizing the 
parameters of the preceding production steps, whereby, for example, open 
soldering points or defective orientations of the components can be 
remedied by refeeding a defective semi-finished product. 
In an advantageous embodiment the system of the present invention is 
constructed in modules, so that the individual modules can be rapidly 
interchanged or replaced. In another embodiment it is possible to divide 
the conveyor into device modules or individual modules with individual 
drive. 
The modular construction of the system according to the invention has 
proven to be advantageous, since the production process can be divided 
into multiple single steps, with the result that energy can be saved owing 
to the functional interaction of the modules, which are in themselves 
separated, within a closed system. 
Another advantage lies in the fact that a process sequence, which is 
predetermined schematically, can be modified in a simple manner by 
removing individual modules from the modularly constructed system and 
exchanging or replacing with other modules. The ease with which the system 
can be serviced is dramatically improved by the easy accessibility of the 
individual modules; thus, the maintainability of the device is 
facilitated. 
Another advantage lies in the automatability through use of coded modules 
and decoders within the system, since in this manner a relatively 
straight-forward management of the modules and automatable quality control 
is possible with the aid of a central computer and a traceability with 
respect to quality standard (ISO 9000) is a given. Dedicated coding for 
each printed circuit board facilitates keeping track of the test history 
of each printed circuit board so that if a printed circuit board fails a 
predetermined number of tests, it is then scrapped without further 
attempts at repair. 
Another advantage lies in the fact that after the printed circuit boards 
leave the soldering device in the first test phase, they can always be 
maintained and used with all components at the same temperature level by 
means of convection of heat from the printed circuit boards themselves, 
which already are at a high temperature as they emerge from the soldering 
station. Thus energy consumption for temperature testing is reduced. 
Another advantage can be seen in the fact that the conveyance of modules 
can be operated with continuous or clocked movement by means of a modular 
conveyor or also in combination optionally with additional acceleration, 
in order to avoid no-load movements for the sake of saving energy and to 
increase the reliability; in addition, the passage time of the modules is 
reduced. 
Furthermore, it is possible to provide by means of a central computer an 
automatable change in width and optionally a central support of the 
transport frame, so that a flexible production program of differently 
formatted modules or printed circuit boards can travel through the system 
according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, wherein like reference numerals designate 
identical or corresponding parts throughout the several views, and more 
particularly to FIGS. 1a and 1b thereof, according to FIGS. 1a and 1b, the 
printed circuit board, shown schematically here as module 1, leaves the 
symbolically illustrated pick-and-place machine 2 along the conveying 
direction X and is fed subsequently to the soldering station 3, which is 
also illustrated symbolically and in which, according to FIG. 1b, the 
temperature is raised to a value as far as exceeding 240.degree. C., in 
order to obtain proper soldering of the printed circuit board as a module 
to the components fitted. After leaving the soldering station 3, the 
printed circuit board 1 passes through a temperature control area 4 where 
the temperature of the printed circuit board 1 is reduced to a range 
between 70.degree. to 125.degree. C. The printed circuit board leaves the 
temperature control area 4 through the closable gate 5 and enters by means 
of the conveyor 6 and by way of buffer region 7 the first test area 8. The 
buffer region 7 serves to uncouple between the soldering station and the 
entry region of the first test area 8, whereby printed circuit boards that 
may or may not have been repaired can also be fed in via the buffer region 
for the purpose of going through the testing process. The test area 8 and 
the preceding buffer region 7 contain an atmosphere in the nominal 
temperature range of +70.degree. to +125.degree. C. This atmosphere is 
protected from external atmosphere by means of a thermal insulation. 
Preferably the internal atmosphere of the first test area 8 consists of 
air, whereby the temperature of the modules under test can be adjusted in 
a set point range of +60.degree. to +130.degree. C. to be specified as 
desired. However, it is also possible to use inert gas, i.e., nitrogen, 
for example. The first test area 8 is sealed with respect to heat and 
atmosphere at least to a high degree from the environment. The test area 8 
is shaped like a continuous tunnel, where to carry the modules away from 
the buffer region 7 into the first test station 9 a fast running conveyor 
belt element 10 of the conveyor 6 is provided. The conveyor 6 is divided 
into device modules, which in turn can be subdivided into individual 
modules, for example, into conveyor belt elements. The conveying movement 
can be operated either continuously, in switched mode or combined 
optionally with continuous acceleration. The region of the conveyor belt 
element 10 has a position sensing system 73 and a scanning system 17, 
which serves to identify, log and sense the position of the modules that 
are fed in and which in turn are provided with a scannable code. Another 
fast conveyor belt element 11 is provided for conveying the modules away 
from the first test station 9 into a second test station 12. To convey the 
modules out of the test station 12, there is another conveyor belt element 
13, which serves to carry the modules from the first test area 8 through 
the gate 14. A second buffer region 15, which is connected to the ambient 
atmosphere and thus serves to cool the modules upon leaving the first test 
area 8, follows the gate 14. 
As in the region of the first conveyor belt element 10, the region of the 
conveyor belt element 16 that follows gate 14 has a scanning system 18, in 
order to control the module, following testing in the test area 8 for the 
purpose of further processing as a function of the test results. The 
recording and control processes are conducted in a central computer, which 
is connected to the scanning systems and the test devices and the 
controllers for the conveyor 6 and for the gates. The second buffer region 
15 has, next to the conveyor 6 running in the X-direction, a sluice 
conveyor 19, which extends perpendicularly to the conveyor 6 and which 
sorts out via gate 20 defective modules, which are denoted here 
symbolically with reference number 21, from the second buffer region 15 in 
the Y direction for the purpose of removal. 
The modules 22 that are determined to be faultless are carried away by 
means of a conveyor 6 via gate 23 into the second test area 74, which 
serves to test the modules at low temperature and is extensively insulated 
with respect to heat against the external atmosphere, just like the first 
test area. Following gate 23 is a conveyor belt element 24, which is 
divided into a fast, a slow and a fast running segment, whereby the region 
of the conveyor belt 24 has a dry air or dry gas inlet 26, through which 
any moisture of condensation can be removed from the modules. Following 
the conveyor belt element is the third test station 27, which, just like 
the test stations of the first test area, is equipped with an adapter for 
contacting the module to be tested. Following test station 27 is another 
conveyor belt element 28 of the conveyor 6, which guides the module in the 
conveying direction X to the gate 29, which defines the second test area 
74 and from where, after passing the opened gate 29, it is guided into a 
sluice area 31, which is also provided with a dry air or dry gas inlet 32. 
After passing through the sluice area 31, the module is guided by means of 
conveyor belt element 33 through gate 34 into a recover-to-ambient 
section, and on into a heating and/or dispensing device 35, on whose end 
36 there is another scanning system 37, which conveys the modules 
determined to be faultless in the X direction for further processing, 
whereas the modules detected as defective are sorted out in the Y 
direction. 
The temperature profile according to FIG. 1b is explained in the following 
with reference to the specification that defines the functions. The 
temperature profile is divided into temperature intervals A, B, C, D, E, 
F, G and H in accordance with the conveying direction X of FIG. 1a. 
According to FIG. 1b, interval A represents the temperature in the 
pick-and-place machine 2, depicted only schematically according to FIG. 
1a, whereas the adjacent temperature increase in interval B reproduces the 
temperature curve along the conveying direction, i.e. the X-axis in the 
reflow soldering station 3, shown schematically. Upon leaving the 
soldering station, the module, provided here schematically with reference 
numeral 1, passes through the cooling area 4, in which the temperature 
according to interval C drops from about 240.degree. C. to 125.degree. C., 
so that, when the module 1 enters into the first test station 9 through 
gate 5, the module 1 brings with it a relatively high temperature level 
with respect to the environment, so that only a small supply of energy is 
required for control purposes within the buffer region 7 and the adjoining 
first test area 8. Within the thermally insulated area formed by means of 
the buffer region 7 and first test area 8 the desired temperature value 
can be set in the range of 25.degree. to 200.degree. C.--preferably from 
+60.degree. to + 130.degree. C. At the same time it is possible to feed 
inert gas, for example nitrogen, to this temperature control region formed 
by the buffer station and the test area, in order to prevent with 
certainty the module or the components fitted or their contacts from 
corroding. Upon leaving the buffer region 7, the module passes by means of 
conveyor belt element 10 through the scanning system 17, which logs the 
type and job number of the incoming module by means of a code found on the 
module and allocates the test result(s) to be expected to the 
corresponding job number. In the first test station 9 the module is 
subjected to a component or in-circuit test, whereby the individual 
components fitted and the conducting tracks of the module are tested. 
Following completion of the incircuit test, the test result is assigned to 
the decoded job number, whereby a defective module is guided by means of 
the conveyor belt elements 11 and 13 without further testing from the test 
area 8 into the second buffer region 15 for the purpose of sorting out, 
whereas a module that has proven to be faultless is guided by means of the 
conveyor belt element 11 of the second test station 12 in order to conduct 
a function test of the entire printed circuit board. A module that is 
determined to be defective is in turn fed to the buffer region 15 via a 
conveyor belt element 13 and gate 14 for the purpose of sorting out of the 
buffer region 15, where the sorting out signal is assigned to the job 
number forwarded to the decoder 18 of the buffer region, and the defective 
module leaves the buffer region 15 for the purpose of sorting out at right 
angles to the conveying direction. A module that is recognized to be 
faultless is cooled to room temperature, according to the temperature 
profile of interval E, after passing through the decoder 18 in the buffer 
region 15, whereby a module that is found to be faultless is fed via gate 
23 and conveyor belt element 24 to the third test station 27 for further 
function testing. The corresponding temperature curve with the drop from 
approximately 100.degree. to approximately--40.degree. C. and maintenance 
is shown in the intervals E and F. Upon leaving the test station 27, the 
module is conveyed by means of the conveyor belt element 28 through gate 
29 from the second test area into the sluicing area 31, whereby the module 
conveyed on the conveyor belt element 33 is heated by means of dry air or 
gas inlet, whereby according to interval G of FIG. 1b the temperature 
rises above room temperature to approximately 40.degree. C., and this 
temperature state is maintained in the heat treating phase of the recover 
to ambient section 41, until all of the moisture or moisture of 
condensation has evaporated. This interval is marked with the letter H in 
FIG. 1b. Upon leaving the recover-to-ambient section 41, the module is 
carried away in the X direction of the dispenser conveyor element 42 and 
detected by means of the decoder 43. If the modules are found to be 
faultless, they are carried away into the next production step or storage. 
If, however, a module is defective, the module found to be defective is 
sorted out of the dispenser 46 in the Y direction, with the result that it 
is carried away, for example by a sluice conveyor, as previously explained 
in regard to the buffer region 7 or buffer region 15. 
FIG. 2 depicts a flow diagram of the sequence control of the module in the 
process according to the invention, whereby the process steps V1-V3, such 
as laser labeling, screen printing and SMD pick and place do not belong to 
the actual subject matter of the process, but are incorporated for the 
sake of better comprehension. 
According to FIG. 2, the modules with, for example, an aluminum plate or 
ceramic plate on the back side are identified through laser labeling, 
where, for example, an optical readable bar code is also-applied, in order 
to enable by means of a computer system a clear allocation of the module 
through optical scanning and its monitoring and/or recording. Furthermore, 
the configurations of the contact fields and conducting tracks in the 
process step V2 are applied, for example, by the screen printing method; 
and in the process step V3 the module is assembled with electronic, 
electromechanical or mechanical components. In the process step V4 the 
components fitted are connected electrically and mechanically through 
soldering, for example, in the soldering station, where subsequently in 
the process step 5 the temperature of the printed circuit board is 
controlled by heating or cooling, in order to maintain a specified test 
temperature. 
Then in the process step V6 the fed-in module is optically scanned by means 
of bar code scanning, whereas in the process step V7 a high temperature 
component or in-circuit testing corresponding to the tests performed in 
the first test station 9 takes place; and in the process step V8 a high 
temperature function test corresponding to testing performed in the second 
test station 12 follows. The test results found in the process steps V7 or 
V8 are assigned to the module coding, which is determined and stored in 
step V6, whereby a poor test result determined in steps V7 or V8 results 
in the coded number, determined beforehand in step V6 being covered with 
the symbol "defective"; and after determining its coding in process step 
V9, the module is fed in accordance with the test result in process step 
V10 to process step V11 for the purpose of sorting out, or if the test 
result is in order, it is fed to process step V12 for the purpose of 
cooling, followed by a subsequent cold temperature test corresponding to 
the test performed in the third test station 27 in process step V13. Then 
in process step 14 the module is carried away via a sluice. In process 
step V15 the module is heated up again in order to allow, following the 
cooling process, the moisture of condensation to evaporate. In process 
step V16 the coding of the module is read out again and the module number 
is allocated to the test result of the cold test determined in the process 
step V13. In the process step V17 the decision is made whether the module 
should be sorted out as defective owing to a module defect in process step 
18 or dispensed as a properly tested module for further processing or such 
as PCB cutting by a PCB cutting machine in step V19 or PCB magazining in 
step V20. 
FIG. 3a shows the modular construction of the device, where for the sake of 
a better overview the individual stations constructed in modules are 
provided throughout with the labels S1 to S14. Elements of the device that 
have already been explained with reference to FIG. 1a are provided 
additionally with the reference numerals known from said FIG. 1a. 
According to FIG. 3a, the modules travel, after leaving the soldering 
station S1, into the first temperature control area 4, comprising the 
separating-station S2, the buffer station S3, the scanning station S4, the 
first test station S5 and the reserved segment S6 for setting the switches 
in order to sort out defective modules S6 and the second test station S7. 
As explained above, the temperature in this first temperature control area 
can be set in a range between 25.degree. to 200.degree. C. 
Upon leaving the station S7, all of the modules travel into an unregulated 
temperature region, where defective modules are sorted out of the testing 
process via the sorting out station S8, whereas modules tested as 
faultless are fed to the temperature control area with the cold profile 
unit S9. In this second temperature control area the modules are adjusted 
to a specified temperature ranging from -50.degree. to +25.degree. C. At 
the same time they are fed to the third testing station (inline test) S10 
along the direction denoted as X and leave the second temperature control 
area via the sluice station S11, which is designed as a cold-hot-sluice 
and enter an uncontrolled temperature region. To prevent the formation of 
condensation water at room temperature and bring the modules back to room 
temperature, the modules are fed, moreover, to a third temperature control 
area with the station heat-profile S12, where the modules that are 
determined to be defective are sorted out of the path leading to the 
dispenser S14 via the second sorting out station S13. 
According to the top view in FIG. 3a, it is also possible to process 
modules of different formats, whereby the variable width and center 
support of the module is done through automatic or manual adjustment of 
the chain drives or belt drives. According to FIG. 3a, the right sided 
belt or chain drives are mounted stationarily, as seen in the conveying 
direction X, whereas the left sided chain drive or belt drive elements and 
optionally a center support for the modules can be adjusted in the 
direction of the Y axis, which is plotted symbolically. With the aid of 
FIG. 3a, the buffer region 7 can be identified, as explained above with 
reference to FIG. 1, that forms together with the first buffer area 8 an 
insulated system that is largely sealed with respect to heat and 
optionally atmosphere against the environment. The modules that emerge 
from the soldering station enter, following a cooling phase, through gate 
5 the buffer region 7, which forms together with the first test area a 
closed thermal system, where upon leaving the buffer region 7, the modules 
pass through a scanning system in order to determine and log the 
respective printed circuit board and then pass through the first test 
station 9 for the purpose of component testing and the second test station 
12 for the purpose of function testing. The test results are allocated, as 
stated above, to the determined module numbers, whereby the defective 
modules are fed, upon leaving the first test area through gate 14, to the 
second buffer region 15, whereby the test results obtained in the test 
stations 9 and 12 are allocated to the respective module numbers; and the 
defective modules are sorted out in the second buffer region 15. The 
modules that are not defective are fed in the conveying direction X to the 
second test area with the third test station 27, whereby this station is 
thermally sealed against the environment for the purpose of cold testing 
and the modules can be fed to it only via gate 29 or carried away via gate 
34. 
According to the device described in FIG. 3a, it is also possible to decode 
the module formats in the scanning system and to adjust the width of the 
modules by means of a central computer and final controlling element in 
order to adjust the width of the conveyor belts or conveyor chains and 
optionally support the center automatically or manually, provided the 
formatting of the modules can be recognized from the coding. 
FIG. 3b is a profile section of the module conveying level 48 and the 
associated buffer regions and test stations along the conveying direction 
X. Furthermore, FIG. 3b shows the sections I--I, II--II, III--III and 
IV--IV, which are respectively depicted in the sectional FIGS. 3c, 3d, 3e 
and 3f. It is apparent from FIG. 3c that the module 45 is in a magazine 
47, whose right side edge rests on the right conveyor chain or the right 
conveyor belt, whereas the left part of the module is situated in a 
magazine 47 on a conveyor chain or conveyor belt having variable 
adjustment in the Y direction. The feeding in or carrying away of 
defective modules is shown symbolically by means of module 44. The upper 
portion of FIG. 3c shows the empty magazines 47, which receive the next 
modules if there is a malfunction. FIG. 3d shows one possible 
configuration of the modules 45 in the second buffer region with 
possibility of sorting out defective modules, whereas FIG. 3e is a 
diagrammatic cross sectional view of the module arrangement with module or 
magazine cycling for the purpose of achieving the temperature in the 
region of the second test area 74. 
FIG. 3f is a cross sectional view similar to that of FIG. 3d of a possible 
arrangement of modules with the possibility of sorting out defective 
modules. 
FIG. 4a is a longitudinal view along the X axis of the test station, 
whereas FIG. 4b is a cross sectional view along the Y axis, from which the 
adjustability of the module adapter relative to the width of the plate is 
apparent. 
According to FIG. 4a, the modules 45 are fed by means of the conveyor belt 
element 10 to the test station, where the module 45 is contacted by an 
upper adapter 52 and a bottom adapter 51, both of which are arranged in 
one of the thermally insulated first or second test areas. The bottom 
adapter 51 is electrically and mechanically connected to the first testing 
device 49 by way of a thermal barrier 68 (shown in FIG. 5) or thermal 
transfer interface, so that the thermal insulation of the atmospheric 
region, formed by the buffer region and the first test area, is largely 
sealed against the exterior environment. The upper adapter 52, which is 
situated above the module 45, is also conveyed, with the exception of its 
thermally insulated passage 50, through the insulating layer 55 to the 
first test area. 
FIG. 4b is a cross sectional view of a corresponding construction, where 
the width adjustment required for different module formats is also taken 
into consideration. According to FIG. 4b, both the left section 53 with 
its conveyor belt or conveyor chain can be adjusted in the Y direction, 
whereas the right section 54 of the conveyor belt or conveyor chain is 
installed stationarily. The construction and mode of operation of the 
adapters 51 and 52 correspond in essence to the arrangements known from 
the literature, as described, for example in U.S. Pat. No. 4,818,933. 
However, one special feature lies in the fact that owing to the thermal 
insulation of the first and second test area the bottom adapter 51 is also 
extensively insulated with respect to heat, due to the thermal barrier, 
from the testing device 49 operating at room temperature. The construction 
of such thermal barriers is explained in detail with reference to the 
adapter, as shown by means of the extractions in FIG. 5. 
According to FIG. 5, the bottom adapter 51 is provided with receiving 
sockets 56, which are arranged in the shape of a grid and in which are 
arranged at least some contact elements 57, which are connected 
electrically to the test pins 58, which are guided through the 
electrically insulating bottom adapter plate 59. A corresponding test pin 
configuration can also be arranged in the upper adapter 52, whereby the 
test pin 60 of the upper adapter is guided through the bottom adapter 
plate 61 of the upper adapter. The electrical connection is transferred to 
the upper test pins 60 via contact elements 57, their connection 63 to the 
transfer test pin 62 and a wire connection 64 to the test pin 60. The 
contact positions of the module 45 with the positions of the test pins is 
allocated exactly with the aid of an adjusting pin 66, which reaches into 
a recess 67 of the module 45. This device is known in principle from U.S. 
Pat. No. 4,818,933, so that further explanations concerning the adapter 
and the module are unnecessary. However, it is essential with respect to 
the high temperature testing in the first test area or the low temperature 
testing in the second test area that it is possible to thermally uncouple 
the adapters, which can be thermally stressed and are situated in the 
respective test area region, and the respective testing device 49. To this 
end, there is a thermal barrier 68, which is arranged between the grid 
plate 67 of the bottom adapter 51 and a grid plate situated above the 
testing device 49 and which is made of a thermally insulating material and 
enables a small passage of heat on account of adequate space between test 
station and adapter. The grid plate 67 is attached to the testing device 
by means of the pins 69, which project beyond the thermal barrier 68 and 
which are connected via flexible conductors or wires 70 to the receiving 
sockets 71 of a bottom grid plate, which defines the thermal barrier and 
into which project the pins 72 that project beyond the test station for 
the purpose of contact. 
Thus, it is guaranteed that a test station functioning in the room 
temperature range, as known, for example, from U.S. Pat. No. 4,818,933, 
can also be used for the subject matter of the invention with few 
modifications for the purpose of erecting a thermal barrier. 
Obviously, numerous modifications and variations of the present invention 
are possible in light of the above teachings. It is therefore to be 
understood that within the scope of the appended claims, the invention may 
be practiced otherwise than as specifically described herein.