JPH0671037B2 - Continuous wafer cooling device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a continuous wafer cooling device capable of continuously measuring various characteristics of a semiconductor element at a cryogenic temperature in a wafer state.

[Problems to be Solved by Conventional Techniques and Inventions] In recent years, semiconductor materials and devices that operate at low temperatures have been actively developed due to demands for high-speed computers and the like. is necessary.

However, conventionally, a method has been adopted in which individual chips formed in a wafer shape are cut out, a test lead is attached to each chip, a protective means is provided, and then the chip is cooled to conduct an electrical characteristic test. However, in such a method, it takes a lot of time and labor to cut out the element and the like, and a great deal of labor and time must be spent.

In view of such circumstances, recently, an apparatus having a probe and capable of measuring various characteristics of an element at a low temperature in a wafer state has been developed.

However, even with such an apparatus, it is necessary to repeat the cooling / heating process every time the element is replaced, and it takes a lot of time to measure the characteristics of many kinds of elements continuously. There was a drawback that it required.

Further, the wafer mounting table may vibrate slightly due to the vibration of the refrigerator body, and stable measurement may not be possible in some cases.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a continuous wafer cooling device capable of continuously and stably performing semiconductor element evaluation and test in a wafer state. To do.

[Means for Solving the Problems] In order to achieve the above object, a continuous wafer cooling device of the present invention has a built-in mounting base for a semiconductor wafer to be tested, and measures the electrical characteristics of the semiconductor wafer by a prober. In a continuous wafer cooling device, a preliminary chamber having a semiconductor wafer loading / unloading port, an actuator having an arm capable of holding the semiconductor wafer inserted from the loading / unloading port and transporting the semiconductor wafer, and an arbitrary immovable part On the other hand, a base supported by a fixed rod connected through a bellows and arranged above the cooling head, a lower plate having a semiconductor wafer mounting portion and arranged on the base, and a clamp portion. In addition, the semiconductor wafer, which is carried and is supported by a movable rod that is connected to an arbitrary immovable part via a bellows so as to be movable up and down, is clamped. A semiconductor wafer mounting table having an upper plate that can be mounted on the mounting portion of the lower plate from above the arm, the semiconductor wafer mounting table is accommodated, and the semiconductor wafer mounting table is adjacent to the preliminary chamber via a gate valve. A measurement chamber provided with a refrigerator, a refrigerator in which a cooling head faces the measurement chamber, and a copper braiding wire that is a heat transfer member that connects the cooling head of the refrigerator and the semiconductor wafer mounting table, A vacuum device capable of evacuating the preliminary chamber and the measurement chamber, and provided so that the low temperature test of the semiconductor wafer can be continuously performed by keeping the measurement chamber constantly in vacuum. And

[Embodiment] Hereinafter, an embodiment of the present invention shown in the drawings will be described in more detail.

In the figure, reference numeral 1 denotes a cooling device of this embodiment, which is configured to include a preparatory chamber 2, a measurement chamber 4, a refrigerator 7, and the like.

The preliminary chamber 2 is formed with a semiconductor wafer loading / unloading port, a semiconductor wafer transfer arm is movably disposed in the preliminary chamber 2, and a closed space can be formed. If not, it is not particularly limited.

In this embodiment, as shown in FIGS. 3A to 3D, two tubular bodies are used, and the other tubular body 21 is hermetically sealed to the peripheral wall portion of one tubular body 20 by welding or the like. They were connected and formed into a substantially T shape. In this case, it goes without saying that the T-shaped auxiliary chamber 2 may be integrally formed.

The one end opening of the one cylindrical body 20 functions as a semiconductor wafer loading / unloading port, and the lid 22 is vertically moved with respect to this loading / unloading port by an air cylinder (not shown) as shown by the dotted line in FIG. It is slidably attached to or detachable from with a screw or the like to open or close the inlet / outlet port. The other end opening of the tubular body 20 is closed by a disc 23. Reference numeral 24 denotes an actuator connecting portion which is provided on the peripheral wall portion of the one cylindrical body 20 so as to project from an opening 20a opened so as to face the other cylindrical body 21. Reference numeral 25 denotes an observation window for confirming the internal state, which is provided near the upper portion of the peripheral wall of the one tubular body 20. Further, a mounting protrusion 26 for fixing to an immovable portion is provided near the lower portion of the peripheral wall.

At the rear end opening of the other tubular body 21, a flange 21 is
a is provided so that it can be connected to a gate valve 5 described later.

The actuator 3 is, as shown in FIG. 1, a cylinder 3
1, a structure having a rod 32 and a semiconductor wafer holding arm 33 attached to the tip of the rod 32, and sliding the rod 32 using a magnet incorporated in the rod 32. Then, the rod 32 and the arm 33 are inserted through the opening 20a provided in the peripheral wall of the tubular body 20 to face the inside of the tubular body 20, and the tip end of the cylinder 31 is airtightly connected to the connecting portion 24. It is arranged at a predetermined position of the device 1.

As shown in FIGS. 1 and 2, the measurement chamber 4 is formed in, for example, a substantially box shape and is arranged adjacent to the preliminary chamber 2.
Further, a cylindrical port 41 of the same diameter is formed in a protruding manner at a position of the auxiliary chamber 2 facing the rear end opening of the second cylindrical body 21, and a flange 41a is provided on the peripheral portion thereof. There is. The measurement room 4 is a machine room 8 in which a refrigerator 7 described later and the like are installed.
On the other hand, it is partitioned by a partition wall 6.

As shown in FIG. 4, the gate valve 5 includes two flanges 51, 51, a partition plate 52 for partitioning a hollow portion 51a between the flanges 51, 51, and a drive unit 53 for operating the partition plate 52. Configured to have. And the other tubular body of the preliminary chamber 2
Flange 21a of 21 and flange 4 of cylindrical port 41 of measurement chamber 4
It is fixedly arranged between 1a and 1a.

The refrigerator 7 is composed of a cooling head 7a and a compressor (not shown), and is not particularly limited as long as it is a cryogenic refrigerator having an ability to operate in a temperature range of about 30 to 300K.

In this refrigerator 7, a cooling head 7a is provided inside the measurement chamber 4 through a mounting hole (not shown) formed in a partition wall 6 which partitions the measurement chamber 4 and a machine chamber 8 provided below the measurement chamber 4. It is fixedly arranged so as to face it.

A semiconductor wafer mounting table 10 for mounting a semiconductor wafer is arranged above the cooling head 7a in the measurement chamber 4. As shown in FIG. 5, the mounting table 10 is composed of a copper plate, a base 101, a lower plate 102 having a substantially U-shaped cross-section mounted on the upper part of the base 101, and a predetermined diameter at a substantially central portion. And an upper plate 103 having a window portion 103a formed therein.

The base 101 is supported by an arbitrary immovable portion, for example, four fixing rods 104 connected to a fixing portion 17a of a fixed shaft 17 that is provided so as to project in the machine room 8. In FIG. 1, reference numeral 11 is a bellows that is loaded around the refrigerator 7 and has one end fixed to the flange 7b of the refrigerator 7. The other end of the bellows 11 is fixed shaft 17 The vibration of the refrigerator 7 can be absorbed by being connected to the fixed portion 17a.

Reference numeral 105 denotes a movable rod, which is connected to a drive rod 17d driven by a motor 17c. The movable rod 105 is connected to the upper plate 103 and supports the upper plate 103 so as to be vertically movable. The motor 17c
Is disposed on the bottom plate member 17b connected to one end of the fixed shaft 17.

Reference numeral 12 is a bellows provided around the movable rod 105, one end of which is provided on a flange 105a projecting from the movable rod 105, and the other end of which is fixedly attached to the fixed portion 17a of the fixed shaft 17, Like the bellows 11, the vibration of the refrigerator 7 is absorbed.

Further, as shown in FIG. 5, clamp portions 103a projecting downward are provided near both sides of the upper plate 103, and the lower plate 102 is provided at a position corresponding to the clamp 103a. A clamp receiving portion 102a is formed. 102b is an insulating plate member fixed to the upper surface of the lower plate 102,
It functions as a semiconductor wafer mounting part.

107 is a copper braiding wire, and functions as a heat transfer body.
The copper braided wire 107 is used to uniformly cool the entire wafer mounting table 10 by the cooling head 7a, the lower plate 102, and the lower plate 1.
Each end of each member of 02 and the upper plate 103 is fixed and a plurality of members are arranged. The copper braided wire 107 also functions to absorb the vibration of the refrigerator 7 together with the bellows 11 and 12.

Reference numeral 13 schematically shown in FIGS. 1 and 2 is 4
A sheet-shaped shield member in which a metal thin film layer is formed on the surface of the fixed rod 104 of the book, which is wound around the portion facing the measurement chamber 4 and wound, and is arranged to improve cooling efficiency. It As the sheet-like shield member 13, for example, an aluminum vapor-deposited sheet such as Kapton (trade name) manufactured by DuPont can be used. It should be noted that, of course, the winding is performed so that the portion of the mounting table 10 into which the semiconductor wafer is inserted and the window portion 103a of the upper plate 103 into which the prober needle is inserted are opened.

In the measurement chamber 4, in addition to the cooling head 7a and the mounting table 10 described above, a prober (not shown) is arranged. This prober may be a conventionally known one, and for example, a prober having a stage movable in the XYZ directions by a movable arm and a probe needle attached to the stage can be used. That is, at the time of measurement, after moving from the standby position in the X or Y direction to a position directly above the wafer mounting table 10, that is, above the window portion 103a of the above-described upper plate 103, the Z direction, that is, the vertical direction. The probe needle is moved to the position of the window portion 103a to be inserted into the window portion 103a, and the probe needle is brought into contact with the semiconductor wafer to measure its electrical characteristics.

In the machine room 8, two vacuum devices are arranged in addition to the refrigerator 7. One is a rotary pump 14, which is connected to each of the preliminary chamber 2 and the measurement chamber 4 by a pipe (not shown), and is arranged to bring the chambers 2 and 4 from atmospheric pressure to a predetermined vacuum degree.

The other is a turbo pump 15, which is arranged in order to make the inside of the measuring chamber 4, which has been brought to a predetermined vacuum degree by the rotary pump 14, to a higher vacuum degree suitable for measurement. In this turbo pump 15, a gate valve 16 is arranged in the middle of the piping portion 15a, and the inside of the measurement chamber 4 can be evacuated by opening and closing the gate valve 16. The turbo pump 15 is provided with a flange (not shown) protruding from the end of the pipe portion 15a fixed to a mounting hole (not shown) formed in the partition wall 6.

The continuous wafer cooling device 1 of this embodiment is used as follows.

First, the lid 22 is slid upward and opened as shown in FIG. 1, and the semiconductor wafer A to be tested is set on the arm 33 of the actuator 3 from the wafer loading / unloading port. Next, the lid
22 is closed and the rotary pump 14 is operated to bring the interiors of the preliminary chamber 2 and the measurement chamber 4 to a predetermined degree of vacuum. Then, the actuator 3 is operated, the rod 32 is extended, and the arm 33 is moved to above the lower plate 102 of the mounting table 10. At this time, the gate valve 5 is opened in advance.

After moving the arm 33 above the lower plate 102 of the mounting table 10, the movable rod 105 is driven to lift the semiconductor wafer A from above the arm 33 by the clamp portion 103a of the upper plate 103. Then, mount the arm 33 on the mounting table.
10 is moved backward from above the lower plate 102 to the side of the auxiliary chamber 2, and is made to stand by at the original position near the wafer loading / unloading port. on the other hand,
The upper plate 103 scoops up the semiconductor wafer A and then descends, and the semiconductor wafer A is lowered to the insulating plate member 1 of the lower plate 102.
Place it on 02b.

Thereafter, the gate valve 5 is operated in the closing direction, and the preparatory chamber 2 and the measuring chamber 3 are partitioned by the partition plate 52. Then, the turbo pump 15 is operated to bring the inside of the measurement chamber 4 into a high vacuum state suitable for measurement. In addition, the refrigerator 7 is operated in advance before performing the above-described operation.

After the temperature inside the measurement chamber 4 reaches a predetermined temperature, the stage of the prober is moved in the Y direction, for example, so that the probe needle is located directly above the semiconductor wafer A. Next, the stage is moved in the Z direction and the probe needle is moved to the window portion 1 of the upper plate 103.
It is inserted from 03a and brought into contact with the semiconductor wafer A, and the electrical characteristics of the semiconductor wafer A are measured.

At this time, in the present embodiment, since the fixed rod 104 and the movable rod 105 that support the mounting table 10 are arranged via the bellows 11 and 12, it is possible to reduce the vibration of the refrigerator 7 and to accurately The measurement is taken. Further, since the cooling head 7 and the predetermined portion of the mounting table 10 are connected by the copper braid 107, the entire semiconductor wafer A can be frozen uniformly, and the copper braid 107 also absorbs vibration. Be done. Further, since the sheet-shaped shield member 13 is provided, the cooling time can be shortened as compared with the conventional case.

After the measurement, the partition plate 52 of the gate valve 5 is moved in the opening direction and the actuator 3 is operated to move the arm.
33 is moved forward to the mounting table 10 again. Then, the semiconductor wafer A lifted by the clamp portion 103a of the upper plate 103 is placed on the arm 33, and the rod 32 is retracted to return the arm 33 to the original position. At the same time
The gate valve 5 is closed.

After the arm 33 returns to the original position, the lid 22 is opened, the measured semiconductor wafer A is taken out, the next semiconductor wafer A to be tested is placed on the arm 33, and the above operation is repeated.

Since the measurement chamber 4 and the preliminary chamber 2 are partitioned by the gate valve 5, even if the inside of the preliminary chamber 2 becomes atmospheric pressure due to the exchange of the semiconductor wafer A, the inside of the measurement chamber 4 is always maintained in a vacuum state. The mounting table 10 is also maintained at a low temperature.

[Advantages of the Invention] According to the continuous wafer cooling device of the present invention, since the measurement chamber is always kept in a vacuum state and the mounting table is kept in a low temperature state, Since it is not necessary to repeat the cooling / heating process, the measurement time for continuous measurement can be significantly shortened as compared with the conventional method.

Further, since the semiconductor wafer mounting table in the measurement chamber is supported via the bellows and is connected to the refrigerator by the copper braiding wire, efficient cooling can be performed. Also, because it is possible to absorb the vibration of the refrigerator,
The electrical characteristics of the semiconductor wafer can be accurately measured.

[Brief description of drawings]

FIG. 1 is a vertical sectional view schematically showing an embodiment of a continuous type wafer cooling device of the present invention. FIG. 2 is a view taken along the line II-II in FIG. FIG. 3 is a view showing the structure of the preliminary chamber,
(A) is a plan view, (b) is a rear view, (c) is a side view,
(D) is a front view. FIG. 4 is a perspective view showing a gate valve. FIG. 5 is a perspective view showing the arrangement relationship between the semiconductor wafer mounting table and the cooling head. 1 …… Continuous wafer cooling device 2 …… Spare room 3 …… Actuator 4 …… Measuring room 5,16 …… Gate valve 6 …… Differential partition 7 …… Refrigerator 8 …… Machine room 10 …… Semiconductor wafer mounting table 11,12 …… Bellows 13 …… Sheet-shaped shield member 14 …… Rotary pump 15 …… Turbo pump 17 …… Fixed shaft

Claims (2)

[Claims] 1. A continuous wafer cooling device having a mounting table for a semiconductor wafer to be tested built therein and measuring the electrical characteristics of the semiconductor wafer by a prober, the auxiliary chamber having a semiconductor wafer loading / unloading port, and the loading / unloading chamber. An actuator having an arm capable of holding the semiconductor wafer inserted through the mouth and carrying the semiconductor wafer, and a fixed rod connected to an arbitrary immovable portion through a bellows are supported and arranged above the cooling head. And a lower plate which has a semiconductor wafer mounting portion and is arranged on the base, and a clamp portion, which is connected to an arbitrary immovable portion through a bellows so as to be vertically movable. An upper plate that is supported by the movable rod that has been transferred and that can carry the transferred semiconductor wafer from the upper part of the arm to the mounting part of the lower plate by a clamp part. A semiconductor wafer mounting table, a measurement chamber that accommodates the semiconductor wafer mounting table and is provided adjacent to the preliminary chamber via a gate valve, and a refrigeration in which a cooling head faces the measurement chamber. Machine, a copper braiding wire that is a heat transfer body that connects the cooling head of the refrigerator and the semiconductor wafer mounting table, and a vacuum device that can evacuate the preliminary chamber and the measurement chamber. A continuous-type wafer cooling device, which is provided so that a low-temperature test of semiconductor wafers can be continuously performed by constantly maintaining a vacuum chamber. 2. A sheet-shaped shield member having a metal thin film layer formed on the surface thereof is wound around at least the fixed rods and wound around the fixed rod so as to surround the cooling head. The continuous wafer cooling device described.