Heat exchange – With alarm – indicator – signal – register – recorder – test or...
Reexamination Certificate
1999-07-21
2001-07-10
Wayner, William (Department: 2858)
Heat exchange
With alarm, indicator, signal, register, recorder, test or...
C062S091000, C324S760020, C374S045000
Reexamination Certificate
active
06257319
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an IC testing apparatus for testing a variety of electric parts, such as semiconductor integrated circuit devices (hereinafter referred to as an “IC” or “ICs”), particularly relates to an IC testing apparatus having a device for giving a low temperature thermal stress.
2. Description of the Related Art
An IC testing apparatus called a “handler” conveys a large number of ICs held on a tray to the inside of a testing apparatus where the ICs are made to electrically contact a test head, then the IC testing unit (hereinafter, also referred to as a tester) is made to perform the test. When the test is ended, the ICs are conveyed out from the test head and reloaded on trays in accordance with the results of the tests so as to classify them into categories of good ICs and defective ones.
When roughly dividing handlers of the related arts in terms of forms of giving a thermal stress, there are handlers of a chamber form in which the ICs to be tested are reloaded to an exclusive tray called a test tray, transferred into a thermal stress applying chamber and made to become a predetermined temperature before being pressed against a test head in a state being carried on the test tray, and handlers of a heat plate form in which the ICs to be tested are carried on a heat plate (also referred to as a hot plate) to be given a high temperature thermal stress and are pressed against the test head while a plurality of the ICs are simultaneously picked up by a pick-up head.
Especially, when testing by giving a low temperature thermal stress, a handler of the chamber form is mainly used, wherein a low temperature stress of for example about −30° C. is given to the ICs by introducing liquid nitrogen into the chamber.
When giving a low temperature stress at a handler, a supply source of liquid nitrogen is necessary as explained above. In the related art, it was drawn to the handler from a liquid nitrogen storage provided separately from the handler by using a plant piping system, or it was supplied by providing a liquid nitrogen cylinder near the handler to supply it to the handler through pipes, etc.
When configuring to press to send the liquid nitrogen by plant pipes from the liquid nitrogen storage provided separately from the handler, however, there have been disadvantages that a space for handling the plant pipes became limited and costs on the equipment for heat-retention and others, became high. Although such disadvantages can be solved when providing the liquid nitrogen cylinder near the handler, a new disadvantage like troublesomeness of exchanging the cylinder arises.
Further, since liquid nitrogen is a substance which has to be handled with precautions and cannot be used carelessly. Thus, it is necessary to be aware of sufficient countermeasures which also ends up in an increase of the cost.
Accordingly, inventors of the present invention developed an IC testing apparatus having a equipment for giving a thermal stress in place for liquid nitrogen. However, the thermal stress applying equipment and the handler have to be connected by a duct, etc. in order to supply a cold air from the thermal stress applying equipment to the thermal stress applying chamber. In such a case, since the duct has to be removed for maintenance of the inside of the thermal stress applying chamber and exchange of a change kit, it has been demanded to develop along with it the connection structure of the duct capable of keeping a sufficient air tightness and being detached and attached easily.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an IC testing apparatus having a thermal stress applying equipment in place for liquid nitrogen.
(1) According to the first aspect of the present invention, there is provided an IC testing apparatus for testing by applying at least a low temperature thermal stress to an electronic device to be tested comprising:
a refrigerant cycle wherein at least a compressor, a condenser, an expansion valve and an evaporator are connected in this order by a refrigerant lines;
a cold air applying line having a blower for supplying heat exchanged air by the evaporator to the pre-test electronic device to be tested.
In the IC testing apparatus of the present invention, since low temperature thermal stress is applied to the electronic device to be tested by generating a cold air in a refrigerating circle, all of the disadvantages can be solved, such as disadvantages on a space for handling plant pipes, equipment costs, and a security comparing with a case using liquid nitrogen.
(2) In the above invention, it is not particularly limited but the cold air applying line preferably supplies the cold air to either one of the soak chamber for raising or lowering the temperature of the electronic device to be tested and the test chamber for testing the electronic device to be tested, and discharges the air from the other.
In the IC testing apparatus of the present invention, the cold air from the cold air applying line may be flown from the soak chamber to the test chamber or inversely from the test chamber to the soak chamber.
By supplying the cold air from the cold air applying line to the soak chamber and discharging it from the test chamber, the efficiency of raising or lowering the temperature of the electronic device to be tested improves in the soak chamber. Also, by introducing the cold air supplied to the soak chamber to the test chamber, it is possible to contribute to maintain the temperature in the test chamber.
Inversely, by supplying the cold air from the cold air applying line to the test chamber and discharging it from the soak chamber, the cold air of a suitable temperature is supplied to the test chamber where a temperature controlling is needed most. Thus, the temperature accuracy of the electronic device to be tested improves. Also, by introducing the cold air supplied to the test chamber to the soak chamber and discharging it therefrom, it also contributes to controlling of raising or lowering a temperature in the soak chamber.
(3) In the above invention, it is not particularly limited, but preferably, the cold air supplying line further comprises a heating unit for heating heat exchanged air by the evaporator.
To control the temperature of the cold air only by the refrigerating cycle, it is sufficient to control the amount of the refrigerant circulating in the evaporator and the rotation rate of the blower, etc. However, since the IC testing apparatus of the present invention comprises a heating unit, it is sufficient to heat the cold air after passing the evaporator to raise the temperature exactly as desired. Accordingly, it is easy to control the temperature of the cold air accurately.
(4) In the above invention, it is not particularly limited, but preferably comprises an input means for inputting a set temperature; a temperature sensor provided on at least either one of the test chamber or the soak chamber; and a control means for controlling a temperature of the cold air supplied from the cold air applying line based on an actual temperature detected by the temperature sensor and the set temperature input to the input means.
In the IC testing apparatus of the present invention, the actual temperature of the chamber being supplied the cold air is detected and compared with the set temperature and thereby the temperature of the cold air supplied from the cold air supplying line is controlled. Therefore, the temperature can be controlled accurately and reliability of tests of electronic device improves.
(5) In the above invention, it is not particularly limited, but the control means preferably controls the temperature of the cold air supplied from the cold air applying line by controlling the blower and/or the heating unit.
As explained above, the temperature of the cold air supplied form the cold air applying line is properly adjustable by the supply amount of the cold air by the blower or heating of the cold air by the heating unit, or by combination of the tw
Igarashi Noriyuki
Kainuma Tadashi
Masuda Noboru
Nakajima Haruki
Nansai Yuichi
Advantest Corporation
Birch & Stewart Kolasch & Birch, LLP
Wayner William
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