JPS6242538Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a semiconductor wafer inspection apparatus, in particular, a semiconductor wafer is placed on a stage in a vacuum container, and a probe is brought into contact with a predetermined position of the semiconductor wafer in a vacuum atmosphere. This invention relates to an inspection device that performs inspection by changing the temperature.

Semiconductor wafers for manufacturing semiconductors are made by thinly slicing a semiconductor single crystal, polishing the surface, and performing chemical treatment if necessary to expose a clean crystal surface. By cutting this semiconductor wafer into small pieces, pellets can be obtained. The semiconductor wafer is subjected to various evaluations in this state.
In this evaluation, the wafer is placed on a circular stage that is approximately the same size as the semiconductor wafer, and the electrical characteristics are measured by bringing a probe into contact with the oxide film formed on the wafer's surface. .

If it is desired to perform this measurement at various temperatures, the stage on which the semiconductor wafer is placed is housed in a sealed container, and heating and cooling means are provided within the stage. Therefore, measurements are performed while changing the temperature of the semiconductor wafer. At this time, the semiconductor wafer is attracted to the stage by vacuum suction, and is held securely and
Its deformation will also be prevented. However, if the atmosphere exists in the container housing the stage, as the temperature of the semiconductor wafer is gradually lowered, moisture in the atmosphere will condense on the wafer, and as the temperature is further lowered, the condensed moisture will becomes frost. Since current flows through this frost, the oxide film is short-circuited, making measurement impossible. Therefore, when performing measurements over a wide temperature range, it is necessary to use a vacuum container as the container housing the stage and perform the inspection in a vacuum atmosphere.

However, if the wafer is inspected in a vacuum container in order to perform measurements over a wide temperature range, it becomes impossible to vacuum the semiconductor wafer to the stage. Therefore, although the semiconductor wafer is held down almost entirely by leaf springs,
The part that comes into contact with the probe cannot necessarily be securely pressed against the stage. Further, when the temperature of the wafer changes, problems such as the wafer being thermally deformed and warped occur. Furthermore, if the wafer is deformed, problems such as the probe coming off from the oxide film will occur. Furthermore, since the wafer is placed in a vacuum container, in order to correct the contact position of the probe, air must be introduced into the container, the container must be opened, and once the probe position has been corrected, the container must be evacuated again. The process becomes extremely complicated.

The present invention was developed in view of these problems, and it prevents deformation due to temperature of at least the portion of the wafer on a stage placed in a vacuum container that comes into contact with the probe, thereby preventing the probe from deforming. It is an object of the present invention to provide a semiconductor wafer inspection device that can reliably maintain contact with a predetermined position of a semiconductor wafer.

The present invention will be explained below with reference to an illustrated embodiment.
1 and 2 show an inspection apparatus according to this embodiment, and this inspection apparatus is equipped with a vacuum container 1 as shown in FIG. The vacuum container 1 includes a bottom plate 2 and a cylindrical body 3 that is mounted upright on the outer periphery of the bottom plate 2.
A joining ring 4 is attached to the upper end of the cylinder 3, and a groove 6 is formed in the joining ring 4 to accommodate an O-ring 5 for sealing. On the other hand, the lid of the container 1 consists of an upper plate 7 and a cylindrical body 8, and a joining ring 9 is attached to the lower end of the cylinder 8.
is installed. This ring 9 comes into contact with the O-ring 5. A handle 10 is attached to the top plate of the lid body 7, and a window made of quartz glass 12 held down by a holding ring 11 is formed in the center thereof.

Next, the structure inside the vacuum container 1 will be described. A stage 13 as shown in FIGS. 1 and 2 is provided approximately in the center of the container 1. This stage 13 is configured in the shape of a disk, and has a diameter slightly larger than 5 inches so that a maximum of 5 inches of semiconductor wafer can be placed thereon. A recess 14 is formed on the lower surface of the stage 13 as shown in FIG.
Inside is a hollow pipe 1 for passing liquid nitrogen.
5, and a heater tube 17 into which a heating element 16 is inserted.
are stored alternately and together in a spiral shape. Hollow pipe 15 for passing liquid nitrogen
Both ends are connected to connection pipes 18 and 19 passing through the bottom plate 2, as shown in FIG. Therefore, liquid nitrogen is supplied through the connecting pipe 18, and liquid nitrogen is discharged through the other pipe 19.

On the outer peripheral side of the stage 13 of the vacuum container 1,
A ring-shaped support plate 20 is arranged, and this support plate 20 is supported on the bottom plate 2 by a rod 21. Note that this support plate 20 is made of a magnetic material. A holding plate 22 made up of a pair of leaf springs is attached to this support plate 20, and is adapted to hold down substantially the entire semiconductor wafer 23 on the stage 13. Furthermore, a support stand 24 is attached to the support plate 20 by a magnet. A leaf spring 2 is attached to the tip side of the support base 24.
5 extends, and a probe 26 is attached to the tip of this leaf spring 25. probe 26
constitutes a contact that is brought into contact with, for example, the oxide film of the semiconductor wafer 23 and extracts a signal for measuring the electrical characteristics of the semiconductor wafer.

Furthermore, on the ring-shaped support plate 20 arranged around the outer periphery of the stage 13, there are, for example, three support stands 27.
is installed. Each of the support stands 27 is equipped with a magnet 28, and the magnetic pole portion of the magnet 28 is attracted to the ring-shaped support plate 20. Furthermore, a through hole 29 is passed through the support base 27 in the lateral direction, and a rod 30 is inserted through the through hole 29. Note that the rod 30 is protruded by an appropriate length, and in this state is fixed by an adjusting screw 31. A sleeve 32 is vertically attached to the tip of the rod 30, as shown in FIG. This sleeve 3
A coil spring 33 is disposed within the coil spring 2, and a pin 35 is slidably supported by a guide tube 34 on the distal end side of the coil spring 33. And this pin 35
A spring receiver 36 attached to the upper end of is pressed by the coil spring 33. A pusher 37 made of an insulating material, such as synthetic resin or ceramic, is attached to the tip of the pin 35. It is starting to press down on the surrounding area.

Next, the operation of the inspection apparatus having the above configuration will be explained. First, the lid consisting of the top plate 7 and the cylindrical body 8 of the vacuum container 1 is removed, and the semiconductor wafer 23 to be inspected is placed on the stage 13 inside the container 1. Then, the semiconductor wafer 23 is substantially entirely held down by a pair of holding plates 22. This presser plate 2
The holding by 2 is performed at the peripheral edge of the wafer 23. Next, a support base 24 that supports the probe 26 via the leaf spring 25 is placed at a predetermined position on the support plate 20 so that the probe 26 comes into contact with a predetermined position on the wafer 23 . This support stand 24 is attracted and fixed to the support plate 20 by a magnet.

Next, as shown in FIG. 2, a support base 27 supporting a pin 35 having a presser 37 at its tip is placed in a position where these pressers 37 press the wafer 23 in the vicinity of the position where the probe 26 contacts the wafer 23. The support stand 27 is placed on the support plate 20 so as to press it. These supports 27 are also fixed to the support plate 20 by magnets 28.

In this state, the lid consisting of the top plate 7 and the cylindrical body 8 of the container 1 is closed and sealed by the O-ring 5 disposed between the joining rings 4 and 9. In this state, the air inside the container 1 is vacuum-sucked by the suction pipe 38. This vacuum suction is continued until the degree of vacuum within the container 1 reaches approximately 10 _-2 to _{10 -3} Torr. When a predetermined degree of vacuum is obtained, the stage 13 is heated by the heating element 16 in the heater tube 17 provided in the recess 14, or the hollow pipe 15 is cooled by passing liquid nitrogen. In this embodiment, the temperature of the semiconductor wafer 23 can be changed between -195°C and +199°C. While changing the temperature of the semiconductor wafer 23 in this way, the probe 26
The wafer 23 is evaluated by extracting a current or voltage by using the current or voltage.

Since this test is conducted in the vacuum chamber 1 as described above, it is possible to prevent moisture in the air from condensing on the wafer 23 when the temperature is lowered. Even if the semiconductor wafer 23 is rough, frost will not form on the semiconductor wafer 23.

Furthermore, a semiconductor wafer 23 is placed inside the vacuum container 1.
The wafer 23 is subjected to temperature changes over a wide range, and this causes the wafer 23 to deform.
However, in the vicinity of the probe 26, the wafer 23 is in contact with the pusher 37, and the pusher 37 is in contact with the coil spring 33 as shown in FIG.
is elastically pressed by the pin 35. In other words, the semiconductor wafer 23 is pressed onto the stage 13 by the three pressers 37 at least in the vicinity of the probe 26 . Therefore, it is possible to prevent deformation of the semiconductor wafer 23 in the vicinity of the position where it contacts the probe 26, thereby making it possible to prevent the probe 26 from deforming.
6 will no longer shift from the predetermined position. Therefore, there is no need to interrupt the measurement and open the lid of the container 1 in order to correct the contact position of the probe 26, and the inspection can be performed efficiently and accurately.

Although the present invention has been described above with reference to an illustrated embodiment,
The present invention is not limited to the above embodiments, and various modifications can be made based on the technical idea of the present invention. For example, the inspection apparatus of the above embodiment relates to an inspection apparatus for semiconductor wafers having a diameter of 5 inches, but the present invention is applicable to inspection apparatuses for wafers of various other sizes. Further, in the above embodiment, the semiconductor wafer 23 is pressed against the stage 13 by three pressers 37 in the vicinity of the position where it contacts the probe 26, but the number of pressers 37 can be increased or decreased as desired. It is possible.

As described above, the present invention provides a pin-shaped member having a presser made of an insulating material at the tip, supports this pin-shaped member by a support means, and elastically attaches the pin-shaped member. The present invention relates to a semiconductor wafer inspection apparatus in which the semiconductor wafer is pressed against a stage near the position of the semiconductor wafer in contact with the probe by the presser. Therefore, according to the present invention, it is possible to eliminate deformation of the semiconductor wafer near the position where it contacts the probe, thereby preventing the probe from shifting from a predetermined position on the semiconductor wafer. Therefore, according to the present invention, it is possible to provide a semiconductor wafer inspection apparatus that can perform inspection quickly and accurately.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a semiconductor wafer inspection device according to an embodiment of the present invention, FIG. 2 is a plan view of the inside of a vacuum container constituting the inspection device, and FIG. 3 is a view of the stage of this inspection device. The bottom view and FIG. 4 are longitudinal sectional views showing a presser for pressing a semiconductor wafer and its support structure. In addition, in the symbols used in the drawings, 1...vacuum container, 13...stage, 23...semiconductor wafer,
26...probe, 27...support stand, 30...rod, 33...coil spring, 35...pin, 37...presser.

Claims (1)

[Scope of utility model registration request] In an apparatus in which a semiconductor wafer is placed on a stage in a vacuum container, a probe is brought into contact with a predetermined position of the semiconductor wafer, and the temperature is changed in a vacuum atmosphere to perform an inspection, the tip is made of an insulating material. A pin-like member is provided with a pusher, and this pin-like member is supported by a support means, and the pin-like member is elastically biased, and the probe of the semiconductor wafer is pushed by the pusher. 1. A semiconductor wafer inspection apparatus, characterized in that a portion near a position where the semiconductor wafer comes into contact with the stage is pressed against the stage.