JPH0426137A - Semiconductor inspecting device - Google Patents

Abstract

PURPOSE:To shorten a cooling time by disposing a window plate made of an infrared ray transmission material at an opposite wafer side from a wafer supporting plate, forming a cooling space between the supporting plate and the window plate, and introducing vapor of cooling liquid to the space. CONSTITUTION:And annular part 6 of a chuck base 3 is cooled by liquid nitrogen N in a cooling vessel 10, and the base 3, a wafer supporting plate 7 and a wafer W are cooled by thermal conduction. The nitrogen N is slightly raised under pressure due to evaporated nitrogen in a vapor supply space 18 formed between the outer periphery of the base 3 and a partition wall 17, the vapor is introduced from a gas passage 15 provided in the base 3 into a cooling space 9 by the pressure, and then the vapor is externally discharged from the space 9 through a gas discharge passage 16 as a nitrogen vapor flow. An infrared light is emitted from below a trestle 1 toward upward in a state that the plate 7 is cooled from the rear surface with the vapor, a probe card is brought into contact with the wafer W to be inspected. Thus, a wafer cooling time can be shortened to improve the inspecting efficiency.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a semiconductor inspection device.

(Prior art and its problems) A back-illuminated infrared sensor such as a CCD is mounted on an integrated circuit (wafer) made of a compound semiconductor material such as InSb.
When fabricated as an integrated circuit (IC), the IC must be tested in wafer form before being diced into individual chips.

Back-illuminated infrared sensors have integrated circuits and electrodes arranged on the front surface of the wafer, and are operated by injecting infrared light from the back surface of the wafer. The chuck is made of a material that transmits infrared light, and can be irradiated with infrared light from the back side of the chuck.

In the above inspection apparatus, the IC wafer and its surroundings can be cooled with liquid nitrogen in order to improve the detection sensitivity to infrared light, that is, the S/N ratio.

By the way, the IC wafer is cooled by cooling the support stand supporting the chuck with liquid nitrogen, and cooling the chuck and IC wafer by heat conduction. However, there are problems in that it takes a long time to cool down and the temperature distribution on the chuck surface tends to be uneven.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a semiconductor inspection apparatus that can improve the wafer cooling method, thereby shortening the cooling time and making the temperature distribution uniform on the chunk surface.

(Means for Solving the Problems) Therefore, in the semiconductor inspection apparatus of the present invention, a semiconductor urchin A for configuring a back-illuminated infrared sensor is supported on a wafer support plate made of an infrared transmitting material such as sapphire, and the above-mentioned In a semiconductor inspection device configured to emit infrared rays from the side opposite to the wafer of the wafer support plate and to cool the semiconductor wafer with a cooling liquid such as liquid nitrogen, infrared rays are emitted from the side opposite to the wafer from the wafer support plate. The present invention is characterized in that a window plate made of a transparent material is disposed, a cooling space is formed between the wafer support plate and the window plate, and the vapor of the cooling liquid is introduced into this cooling space.

(Function) As a result of the above, in addition to being cooled by thermal conduction, the wafer support plate is further cooled by the vapor of the cooling liquid, thereby cooling the wafer. Moreover, since only vapor exists in the cooling space, absorption and scattering of infrared light does not occur as would occur when a cooling liquid is present, so that a stable amount of infrared light transmission can be obtained.

(Example) Next, a specific example of the semiconductor inspection apparatus of the present invention will be described in detail with reference to the drawings.

In FIG. 1, 1 indicates a pedestal, and this pedestal 1
has a heat insulating structure with a through hole 2 in the center. A chuck stand 3 is attached on the pedestal 1. The chuck base 3 is made of a material with good thermal conductivity such as copper.
It consists of a disc part 5 having a through hole 4 in its center, and an annular part 6 extending downward from the outer periphery of this disc part 5. A disk-shaped wafer support plate 7 is attached to the upper surface of the chuck and a disk-shaped window plate 8 to close the through-hole 4 of the chuck and table 3, and a disk-shaped window plate 8 is attached to the lower surface thereof. A cooling space 9 is formed inside thereof.

Both the wafer support plate 7 and the window plate 8 are made of an infrared light transmitting material such as sapphire.

Note that this wafer support plate 7 is configured such that the wafer W can be fixed on its upper surface by means such as suction.

On the other hand, reference numeral 10 denotes a cooling container for storing a cooling liquid, for example, liquid nitrogen N. This cooling container 10 has an inner cylinder 12 and an outer cylinder 13 connected to each other with a bottom surface 14, and has both an inner and outer cylinder. Liquid nitrogen N can be stored between the cylinders 12 and 13. The cooling container 10 is usually preferably a vacuum insulated container.

The upper end of the inner cylinder 12 of the cooling container 10 is attached to the lower surface of the chuck stand 3.

The chuck table 3 includes a gas introduction passage 15 that radially passes through the disc part 5 and communicates between the inside and outside of the disc part 5; A gas outlet passage 16 that opens on the upper surface of each is bored. As shown in FIGS. 2 and 3, six gas inlet passages 15 and six gas outlet passages 16 are provided at equal intervals in the radial direction.

The functions of the gas introduction path 5 and the gas outlet path 16 will be described later. Further, the annular portion 6 of the chuck stand 3 is configured such that its lower end is immersed in the liquid nitrogen N when the liquid nitrogen N is contained in the cooling container 10. Furthermore, an annular partition wall 17 is attached to the chuck stand 3 to cover the outer circumference of the annular portion 6. Although not shown in detail, infrared light is irradiated from the bottom of the pedestal 1 from a blackbody furnace or the like.

The operating state of the above inspection device will be explained. First, the annular portion 6 of the chuck table 3 is cooled by the liquid nitrogen N in the cooling container 10, and the chuck table 3, wafer support plate 7, and wafer W are each cooled by heat conduction. Furthermore, although the liquid nitrogen N evaporates, the pressure in the vapor supply space 18 formed between the outer circumference of the chuck table 3 and the partition wall 17 rises slightly due to the evaporated nitrogen (see Fig. 4). Due to the pressure, nitrogen vapor is introduced into the cooling space 9 from the gas introduction path 15 provided in the chuck table 3,
A flow of nitrogen vapor is then formed which is discharged from the cooling space 9 to the outside via the gas outlet path 16. In this case, the wafer support plate 7 is also cooled from the back surface by nitrogen vapor having a temperature close to the boiling point. In this state, infrared light is irradiated upward from the bottom of the pedestal L, and a probe card (not shown) is brought into contact with the wafer W to perform an inspection.

In the above embodiment, the partition wall 17 is used to form the steam supply space 18, but as shown in FIG.
By changing the structure of the chuck base 3, the chuck base 3 and the partition wall 17 are
It can also be formed by integrally configuring the.

Further, although in the above description the nitrogen vapor generated in the cooling container 10 is introduced into the cooling space 9, a separate vapor supply source may be provided.

(Effects of the Invention) According to the semiconductor inspection device having the above configuration, the wafer support stand is
In addition to cooling by heat conduction, which is almost the same as in the conventional case, cooling is also performed by the vapor of the cooling liquid. Therefore, the wafer cooling time can be reduced compared to the conventional method, and inspection efficiency can be improved. Particularly during initial cooling, the amount of steam released is large, so cooling the wafer support plate with steam is even more effective. It has also been confirmed that the temperature distribution of the wafer support plate is made more uniform than in the case of conventional cooling using only heat conduction, and that this improves inspection accuracy.

Furthermore, in the cooling space through which infrared light passes, there is no liquid,
By adopting a configuration in which steam is introduced, there is an advantage that the amount of transmitted infrared light is stabilized. In other words, when a cooling liquid is introduced, in addition to absorption and scattering of infrared light by the liquid itself in the cooling space located in the optical path, infrared light caused by boiling bubbles of the liquid occurs. This is because absorption and scattering of the infrared light will occur, but in the case of the present application in which gaseous vapor is introduced into the cooling space, the absorption and scattering of the infrared light can be reduced.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view schematically showing an embodiment of the semiconductor inspection apparatus of the present invention, FIG. 2 is a cross-sectional view of the chuck stand used in the above, FIG. 3 is a vertical cross-sectional view thereof, and FIG. An explanatory diagram for explaining the steam flow passing through the cooling space, FIG. 5 is a longitudinal sectional view of a modified example of the chuck stand. 7... Wafer support plate, 8... Window plate, 9. Cooling space,
15... Gas introduction path, 1 (5... Gas outlet path, 18
...Vapour supply space, N...Liquid nitrogen, W...Wafer.

Claims (1)

[Claims] 1. A semiconductor wafer for forming a back-illuminated infrared sensor is supported on a wafer support plate made of an infrared transmitting material such as sapphire, and infrared rays are irradiated from the side opposite the wafer of the wafer support plate, and the semiconductor wafer is In a semiconductor inspection device configured to be cooled with a cooling liquid such as liquid nitrogen, a window plate made of an infrared transmitting material is arranged on the side opposite to the wafer from the wafer support plate, and the window plate is connected to the wafer support plate. A semiconductor inspection device characterized in that a cooling space is formed in between, and the vapor of the cooling liquid is introduced into the cooling space.