JPH03296242A - Wafer support device - Google Patents

Abstract

PURPOSE:To enable a thinned wafer to be handled as a normal wafer by placing the thinned wafer onto a metal plate with a plurality of fine through holes and by pressing a wafer peripheral part with a shape memory alloy ring. CONSTITUTION:A wafer 1 which is fitted to a wafer support device is held to a shape memory alloy ring 3 at room temperature and is fixed to a metal plate 2 which is 0.5-3mm thick. When handling with air tweezers or in wafer chuck of an automatic tester, vacuum is propagated to the wafer 1 through a through hole 4 whose diameter measures 150mum or less. During measurement by a tester, heat generated from a device on a surface of the wafer 1 is trans ferred to the metal plate 2 and then to the wafer chuck. After automatic test ends and when moving to an assembly process, the shape memory alloy ring 3 is deformed by cooling to 0 to -10 deg.C, thus enabling the wafer 1 to be free and the tweezers etc., to be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to the handling of GaAs wafers thinned to 200 μm or less and the automation of DC/RF on-wafer testing.

[Conventional technology]

Fig. 5 is a plan view showing a conventional thinned wafer, Fig. 6 is a sectional view showing a state in which the thinned wafer of Fig. 5 is handled, and Fig. 7 is a perspective view showing a flat case (for 6 wafers). , Fig. 8 is a perspective view showing a flat case (for one wafer), Fig. 9 is a sectional view showing a state where the wafer is bonded to a glass plate to make it thin, and Fig. 10 is a state shown in Fig. 9. FIG. 2 is a cross-sectional view showing a state in which a wafer has been ground and processed into a thin plate. In the figure, (10) is a thinned G, aAs wafer, (1]) is a stainless steel tweezers, and (12) is a flat case (6
(13) is a flat case (for one sheet), (14) is a GaAs wafer with a thickness of 600 μm, (15) is wax, and (16) is a glass plate or ceramic plate.

Next, the operation will be explained. FE on the wafer (14) surface
After forming T, resistors, wiring, capacitors, etc., a protective film is formed and the wafer (14) is bonded to a glass plate or ceramic plate (16) with the back side facing up as shown in FIG. Next, the wafer (14) is polished and polished.
Process to make the plate thinner as shown in the figure. Thinned wafer after processing (l
The thickness of O) varies depending on the model, but is between 20 μm and 200 μm.
It is μm. Next, the thinned wafer (JO) is peeled off from the glass plate or ceramic plate (16), and the protective film, adhesive, etc. are removed and cleaned, and the wafer process is completed. Here, pinch the periphery of the thin plate (1) (2)-treated wafer (10) with the bin set (11), and place a special flat case (for 6 wafers) (12) and a flat case (for 1 wafer) (13). ), etc., and proceed to the test assembly process.In the test process, the periphery of the thinned wafer (10) is also pinched with tweezers (11) and placed on the measurement stage.After the test is completed, the thinned wafer (10) is thinned using the bin set (II). Pinch the periphery of the wafer (10) and lift it from the measurement stage to the flat case (for 6 wafers) (
12) Store it in a flat case (for 1 sheet) (1, 3), etc.

[Problem to be solved by the invention]

Conventional handling of thinned wafers was carried out as described above, requiring skill and caution during the work. The reason for this is that normally the thickness of a wafer is less than 600 μm, so this is not a problem, but thinned wafers with a thickness of 20 to 200 μm are extremely brittle, and if even the slightest amount of force is applied, they will break immediately. . As described above, since skilled workers must carefully handle the thinned wafers, there is a problem in that efficiency is low and the percentage of thinned wafers is extremely large. Furthermore, this made it difficult to automate the testing process.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide a wafer support device that can handle a thinned wafer in the same way as a normal wafer.

[Means to solve the problem]

The wafer support device according to the present invention places a thinned wafer (3 inches in diameter) on a metal plate (4 inches in diameter) having a large number of fine through holes with a diameter of 150 μm or less, and forms a shape made of a shape memory alloy. The area around the sea urchin is held down by a memory alloy ring.

[Effect]

The shape memory alloy ring in this invention has a gap between it and the wafer when it is cooled, and deforms so that there is no gap between it and the wafer at room temperature. It has the role of fixing. or,
The fine through-holes with a diameter of 150 μm or less are used to convey vacuum to the wafer, which is vacuum-adsorbed when placed on a wafer stage (3) (4) such as a blower. The metal plate also serves as a path for dissipating heat generated during wafer testing.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a plan view of the wafer support device, and Figures 2 and 3 are the 1st
2 shows the shape at room temperature, and FIG. 3 shows the shape at low temperature (0° to 10° C.). In the figure, (1) is a GaAs wafer with a diameter of 3 inches that has been thinned to 100 μm or less, (2)
) is a metal plate with a thickness of about 0.5 to 3 mm, and the material is Cu.
The surface is plated with Au using AI, an alloy of Cu and Sn, etc. This shape is 4 inches in diameter and has an orientation flat similar to a Si wafer. (3) is a shape memory alloy ring, a part of which is fixed to the metal plate (2), and whose outer diameter is 10 cm or less (usually 9 cm).
cm or less), the inner diameter is 7.5 cm or less (usually 6.8 cm)
degree). The material is nickel, titanium alloy, copper, aluminum, or zinc alloy, and the thickness is 0.5 to 1.
It is 0mm. (4) is a radius of 3 from the center of metal plate (2)
．． Multiple through holes are provided on the center side from 5cm, and the diameter is 15cm.
It is 0 μm or less.

Next, the seventh operation will be explained. In FIG. 2, the wafer (1) mounted on the wafer support device is held down by the shape memory alloy ring (3) and fixed to the metal plate (2) at room temperature, so that it can be handled with tweezers. Furthermore, it can be stored in a cassette and transported or set in an automatic tester.

When handling in an air bottle set or in a wafer chuck of an automatic tester, vacuum is applied to the wafer (1) through the through hole (4). During measurement with the tester, the heat generated from the devices on the surface of the wafer (1) is transferred to the metal plate (2).
) and then to the wafer chuck. After the automatic test, when moving on to the assembly process, the
By cooling to ℃, the shape memory alloy ring (3) becomes the third
The wafer (1) deforms as shown in the figure and becomes free, so it can be removed with tweezers or the like.

(5) (6) In the above embodiment, the metal plate (2) has a diameter of 150 mm.
A plate made of Cu or the like with through holes (4) of μm or less was used;
A porous metal plate made by sintering fine alloy particles of Cu and Sn may also be used. However, in this case, the gap created by the fine alloy particles of Cu and Sn needs to be smaller than 150 μm.

Furthermore, when the wafer (1) is to be attached or detached from the wafer support device of the above embodiment, automatic attachment or detachment is possible by using a detachment device as shown in FIG. In Figure 4, (1) to (
4) is equivalent to that shown in FIGS. 1 and 2. (
5) is a lower chuck in which a cooling element (6) and a vacuum suction hole (7) are embedded. (8) is an upper chuck, and (9) is a vacuum suction hole. The operation is performed by setting the metal plate (2) on the lower chuck (5) and opening the vacuum suction hole (7).
). Next, the entire lower chuck (5) is cooled to 0°C to -10°C by the cooling element (6), and the shape memory alloy ring (3) is deformed as shown in the figure. on the other hand,
The wafer (1) is adsorbed by the upper chuck (8) and placed on the center of the metal plate (2) by sliding it vertically and horizontally. Next, when cooling by the cooling element (6) is finished, the temperature returns to room temperature as a whole, and either the shape memory alloy ring (3) or the outer circumference of the wafer (1) is fixed. In this state, the vacuum of the upper chuck (8) and lower chuck (5) is turned off and the upper chuck (8) is moved, thereby making it possible to handle the wafer (1) fixed to the wafer support device.

〔Effect of the invention〕

As described above, according to the present invention, a thinned wafer, which is normally difficult to link by hand, is fixed on a metal plate, so it can be transported by hand in a cassette using tweezers, or transferred to an automatic test machine. application, allowing for significant automation of the testing process. By implementing the above automation, wafer cracking, which had occurred frequently in the past, has been reduced.
Yield is improved. As a result, there is an effect that leads to cost reduction.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a wafer support (7) (8) device according to an embodiment of the present invention, FIGS. 2 and 3 are cross-sectional views taken along line A-A shown in FIG. 1, and FIG. is the shape at room temperature,
FIG. 3 shows the shapes in the low temperature state. FIG. 4 is a cross-sectional view showing the configuration of a wafer desorption device to which the above embodiment is applied. Figure 5 is a plan view showing a conventional thinned wafer;
The figure is a cross-sectional view showing a state in which the thinned wafer shown in FIG. , No. 9
The figure is a cross-sectional view showing a state in which the wafer is bonded to a glass plate in order to make it thin, and FIG. 10 is a cross-sectional view showing the state in which the wafer in the state shown in FIG. 9 has been ground and processed to be thin. In the figure, (1) is a wafer, ('2) is a metal plate, (3) is a shape memory alloy ring, (4) is a through hole, (5) is a lower chuck, (6) is a cooling element, and (7) is a through hole. ), (9) is a vacuum suction hole, and (8) is an upper chuck. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.
Agent Masuo Oiwa Figure 1 Figure 2 (9) Figure 3 Figure 4 I3 + Yank Figure 6 Figure 7 (for father of 13)

Claims (1)

[Claims] Thickness: 0.0mm with multiple through holes of 150μm or less in diameter.
A wafer support device comprising a metal plate of 5 mm to 3 mm and a ring-shaped shape memory alloy partially fixed to one side of the metal plate.