JPH042146A - Wafer holder - Google Patents

Abstract

PURPOSE:To enable handling a thinned wafer in the same manner as a normal wafer by supporting a thinned GaAs wafer with a doughnut-shaped metal disc and a doughnut-shaped tape. CONSTITUTION:A metal disc 1 supports a thinned GaAs wafer 2 along with a doughnut-shaped tape 3 and further keeps the randomly curved GaAs wafer 2 planar. As a result, the randomly curved thinned GaAs wafer 2 can be stored in a normally used cassette; therefore, it is possible to apply this holder to an automatic measurement instrument for cassette to cassette.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the production of semiconductor devices, and in particular to the production of semiconductor devices, particularly GaAsl0
The present invention relates to a wafer holder used for wafer handling in back side processes and test/assembly processes.

[Conventional technology]

Conventionally, the back side process of GaAsl0 process is 25 μm ~
Stainless steel tweezers were used to handle the ()aAa wafer that had been thinned to 150 μm lc. FIG. 3 shows an explanatory diagram of handling of a 90aAs wafer processed into a thin plate. Using a stainless steel bottle set (4), pinch the periphery of the wafer (2) as shown in Figure 4 (a).
, Dedicated flat case (5) shown in (b) or (
6) was used for transportation or storage.

Next, the operation will be explained. After forming FETs, resistors, wiring, capacitors, etc. on the surface of the GaAs wafer (2), a protective film is formed and the wafer (2) is pasted onto a glass plate or ceramic plate with the back side facing up. This state is shown in Figure 5←). Next, the GaA8 wafer (7) is processed into a thin plate by grinding, polishing, etching, lapping, etc. The thickness of the GaA3 wafer (2) after the thinning process varies depending on the model, but is 25 μm to 150 μm. This state is shown in FIG. 5 (1,). Next, peel off the GaAs wafer (7) from the glass plate or ceramic plate (9),
The wafer process is completed by removing and cleaning the protective film and adhesive. Grip the peripheral part of this thinned wafer (2) with stainless steel tweezers (4).
1) Store in the dedicated flat case shown in (1)) and proceed to the test assembly process. In the test process, the peripheral part of the thin plate was picked up using cystine-free tweezers (4) and placed on the measurement stage. After the test, pinch the periphery of the thinned wafer with stainless steel tweezers (4).
It is stored from the measurement stage in the dedicated flat case (5) or (6) mentioned above.

[Problem to be solved by the invention]

Conventional handling of thinned wafers involves using stainless steel tweezers to pinch the wafer's periphery to move the wafer, which requires skill and caution during the process. The thickness is ~600
Although this is not a problem due to the presence of PM, thin wafers of 25 to 150 μm are extremely fragile and will break immediately if even the slightest amount of force is applied, so skilled workers must handle the wafers carefully. Therefore, there were problems in that efficiency was poor and the wafer breakage rate was extremely high.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide a wafer holder that allows thinned wafers to be handled in the same way as normal wafers.

[Steps to solve problems]

In the wafer holder according to the first invention, a thinned GaAθ wafer is placed inside a donut-shaped metal disk, and a donut-shaped tape is attached to the outer circumference of the wafer and the inner circumference of the donut-shaped metal disk at the same time. It was pasted using

Further, in the wafer holder according to the second invention, the wafer is placed inside the donut-shaped metal disk so that the outer circumference of the wafer and the inner circumference of the donut-shaped metal disk overlap, and the overlapping portion is are pasted together by thermocompression bonding, soldering, or ultrasonic welding.

[Effect]

In the wafer holder of the present invention, a donut-shaped metal disk serves as a frame to support the thinned wafer, and this allows it to be stored in a commonly used cassette. It serves to bond the thinned wafer and donut-shaped metal disk together.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. Figures 1 (-) and (b) are a plan view and a sectional view of a wafer holder that is an embodiment of the present invention. is a metal disc made of stainless steel, copper, aluminum, silver, brass, nickel, tin, or iron. Alternatively, it may be an alloy or plastic containing at least one of these metals.

The outer diameter is 10 mm (4 inches) and the inner diameter is 74 mm (3 inches - 0.5 mm). (2) is a thinned GaAs wafer (3 inches) with a thickness of 25 to 150 μm.

FETs, resistors, wiring, capacitors, etc. are formed on the surface. (3) is a tape pasted across the inner circumferential portion of the metal disk (1) and the thinned (aAs) wafer.

Next, the operation will be explained.

In FIG. 1(a) or (b), a metal disk (1) is attached to a thin GaAs wafer (2) with a donut-shaped tape (3).
thinned GaAθ that is supported and further curved randomly.
Keep the wafer (2) flat. As a result, the randomly curved thinned GaAs wafer (2) can be stored in a normally used cassette, making it possible to apply it to an automatic cassette-to-cassette measuring device.

Another embodiment of the invention is shown in FIG. 2(a) f (1)).

FIG. 2(a) is a plan view of the wafer holder, and FIG. 2(b) is a sectional view thereof. The material and outer diameter of the metal disk (1) are the same as those in the above embodiment, and the inner diameter is 76 mm (3 inches + 0.5 to 1 mm). The outer periphery of the thinned ()aAθ wafer (2) and the inner periphery of the metal disk (1) overlap, and the back side is flush. The overlapping parts are connected by thermocompression, soldering, or ultrasonic welding.

〔Effect of the invention〕

As described above, according to the present invention, since the thinned GaAs wafer is supported by the donut-shaped metal disk and the donut-shaped tape, the thinned GaAs wafer is not only randomly curved but also easily broken. can now be handled in the same way as regular wafers. Specifically, when a 3-inch thinned GaAs wafer is supported by a 4-inch metal disk, it can be transported and piped using a 4-inch cassette, and it can also be applied to automatic measurements. Further, since the thinned GaAs wafer, which is easily broken, is not directly touched, the wafer cracking rate is greatly reduced. That is, it leads to improvement in work efficiency, improvement in yield, and further, reduction in cost.

[Brief explanation of drawings]

FIGS. 1(a) and (1)) are a plan view and a sectional view of a wafer holder which is an embodiment of the present invention, and FIG. 2(a)
, (b) is a plan view and a sectional view of a wafer holder according to another embodiment of the present invention, and FIG. 3 is a conventional thinned GaAs
Figure 4 shows the state in which the wafer is held with tweezers (
a) and (b) are perspective views of a dedicated flat case for storing conventional thinned GaAs wafers; (a) is for 6 wafers, (
b) is for one sheet. FIG. 5(a), (1:,) is a cross-sectional view of a GaAs wafer before and after thinning processing. In the figure, (1) is a donut-shaped metal disk, (2) is a thinned GaAs wafer, and (3) is a donut-shaped tape. In addition, the same symbols in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A hollow disc-shaped holder having the same outer diameter as a standardized arbitrary wafer diameter larger than the wafer diameter to be held, and having a wafer introduction part opened in the center thereof;
A wafer holder comprising a support fixed to the holder and supporting the wafer introduced into the wafer introducing section. (2) A disc-shaped holder having the same outer diameter as a standardized arbitrary wafer diameter larger than the diameter of the wafer to be held, provided in the center of this holder and larger than the diameter of the wafer to be held. , and a wafer accommodating portion having the same depth as the wafer thickness from one main surface side thereof, and an integrated circuit portion of the wafer provided in the holder and when the held wafer is accommodated in the wafer accommodating portion. A wafer holder characterized by having an opening in which the wafer holder is enclosed.