JPH03204924A - Specimen holder - Google Patents

Abstract

PURPOSE:To manufacture the title specimen holder having high electrostatically holding ability, almost no residual holding ability and high response characteristics of the electrostatically holding force by a method wherein an insulating film contains TiO2 while the volume resistivity of the insulating film is adjusted to have a specific value at specific applicable temperature. CONSTITUTION:A specimen table 2 comprises an Al formed conductor 5 in planar view circular shape coated with an insulating film 6 which is formed on the surface of the conductor 5 by plasma spray coating process. That is, the insulating film 6 is formed on the surface of the conductor 5 by melting down ceramic powder of Al2O3 containing TiO2 not exceeding 25wt.% and adjusting the volume resistivity of the film 6 to be 10<9>-10<11>OMEGA.cm at the applicable temperature not exceeding 100 deg.C at high temperature using plasma to be sprayed. For example, the insulating film 6 is formed at the composition ratio of Al2O3:TiO2=85wt.%:15wt.%. Through these procedures, the title specimen holder displaying high response characteristics resultantly in high electrostatically holding ability having almost no residual holding ability at all can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sample holding device installed in a semiconductor manufacturing device such as a thin film forming device or a dry etching device.

In the thin film forming process and dry etching process in the semiconductor manufacturing process, the sample is firmly attached to the sample stage, the temperature of the sample is controlled to a desired level, and a predetermined high-frequency power is reliably applied to form a thin film. It is necessary to perform forming and etching.

As a sample holding device that satisfies this requirement, a sample holding device that adopts an electrostatic chuck method has been developed in recent years and is becoming popular (Zenben, Bauchi, Kinoshita, Matsutsu et al.: 1985 Spring Conference of the Japan Society for Precision Engineering (See Proceedings of Academic Lectures, p. 73).

The sample holding device uses electrostatic adsorption to bring the sample into close contact with the sample stage, can reliably adsorb the sample over the entire back surface, and has a relatively simple structure. It has the following characteristics.

FIG. 10 is a sectional view showing the main parts of a conventional sample holding device of this type.

That is, in the sample holding device, the sample stage 51 is configured such that a conductor (electrode) 52 such as W (tungsten) is buried near the surface of an insulator 53, and a node terminal 54 is connected to the conductor 52. Then, a voltage is applied between the sample 55 placed on the surface of the sample stage 51 and the conductor 52, and the sample 55 is held on the sample stage 5I by the adsorption action of static electricity.

However, the sample stage 51 is Aj220. It is manufactured by inserting a metal plate such as W into ceramic clay, molding it, and then firing it, which results in high manufacturing costs and a long manufacturing time, resulting in a lack of mass production. There was a point.

Therefore, as a solution to these problems, the first
As shown in FIG. 1, a sample holding device has been proposed, which includes a sample stage 63 in which the surface of a conductor (electrode) 61 is covered with an insulating film 62, and a lead terminal 64 is connected to the conductor 61. (Refer to Utility Model Application Publication No. 11542/1983).

The above sample stage 63 is to! A conductor 6 of a predetermined shape made of metal such as
After molding 1, a ceramic powder made of 1,12203 is sprayed onto the surface of the conductor 61 by plasma spraying to form the insulation 11M62.

Unlike the sample stand 51 described above, the sample stand 63 does not require a baking process that requires a long time, and can be manufactured in a short time.
Moreover, it can be manufactured at low cost.

However, in the sample stage 51 or 63, the insulator 5
3 or the insulating film 62 is 8β203′″: lo.

%, the specific volume resistivity was not optimized and the response characteristics (time to reach saturation adsorption force, time to dissipate adsorption force) were poor.

Furthermore, since this response characteristic changes depending on the set temperature of the test tube 4, that is, changes in temperature of the insulator 53 and the insulating film 62, it is difficult to control it.

Therefore, when the voltage is rOFFJ, there is a considerable amount of residual adsorption force, so when removing the sample 55 from the sample stage 63, the sample 55 is held by a transfer arm or the like having a complicated holding mechanism. 55 to sample stage 63
had to be removed from.

In particular, response characteristics become a problem when the sample temperature is relatively low, such as 100° C. or less. An2 when it exceeds 100℃
0. Since the specific volume resistivity of the material is low, the response characteristics are good and there are no problems in practical use. Therefore, it is desired to improve the response characteristics at a sample temperature of 100° C. or lower.

The present invention was invented in view of these problems, and it generates a large electrostatic adsorption force in a short time at a set temperature to tightly adhere the sample to the sample stage, and after stopping the voltage application, The object of the present invention is to provide a sample holding device that can easily remove a sample from the sample stage and has high response characteristics.

In order to achieve the above object, in the sample holding device according to the present invention, the conductor is coated with an insulating film formed of a ceramic material, and the sample to be placed and the above-mentioned In a sample holding device in which a voltage is applied between a conductor and a sample is adsorbed onto the insulating film, the insulating film contains T i O2 and lo
The specific volume resistivity (hereinafter referred to as "volume resistivity") of the insulating film is 109 to 101 at a usage temperature of o'c or less.
The conductor is coated with an insulating film made of a ceramic material, and a voltage is applied between the sample placed on the conductor and the conductor. In the sample holding device in which a sample is adsorbed onto the insulating film, the insulating film is A8. O, for T i O
2 in a proportion of 25 wt% or less.

In order to improve the electrostatic chucking force in a sample holding device that employs the electrostatic chuck system, it is considered that the dielectric constant of the insulator should be increased to increase the amount of charge that can be stored when voltage is applied.

Furthermore, as a measure to improve the electrostatic attraction force, lowering the volume resistivity can be considered. That is, when a "positive" voltage is applied to the conductor, the surface of the insulator becomes "positively" charged, and the back surface of the sample becomes "negatively" charged. When the volume resistivity is lowered, the negative charge flowing into the insulator from the back side prevents the positive charge on the insulator surface from being electrically neutralized, increasing the electrostatic attraction force. Ru. In other words, by lowering the volume resistivity, the negative charges flowing into the insulator from the back surface of the sample are drawn into the conductor faster than they diffuse to the insulator surface, so the positive charges on the insulator surface are reduced by the negative charges. It is not electrically neutralized and the electrostatic adsorption force is enhanced.

Further, by lowering the volume resistivity, charges can be neutralized smoothly and residual adsorption force can be reduced.

On the other hand, if the equivalent circuit of an electrostatic chuck is considered as a simple capacitor charging/discharging circuit as shown in FIG. 5, the electrostatic force F after t (sj) due to voltage application is expressed as in the following equation (1). In reality, there are effects such as resistance due to leakage current and capacitor components on the surface of the insulating film, but these are excluded from consideration here.

However, R: resistance C: Capacitance S: Electrode area ε: dielectric constant d: Distance between electrodes represents.

From equation (1), in order to optimize the responsiveness of electrostatic force, it is sufficient to control the time constant C-R, and among the time constants C-R, there are many constraints on the capacitance C, and it is difficult to suppress it. However, the resistance R is considered to be highly controllable (and highly effective).

As a method for changing the resistor R1, that is, the volume resistivity of the insulating film formed of a ceramic material, the easiest method is to add impurities, and the controllability is also high. For example, it is known that adding TiO□ as an impurity to A° C. 203 reduces the volume resistivity. T to Al2203
i T at each temperature of the sample stage when O2 is added
FIG. 6 shows the relationship between the amount of iOz added and the volume resistivity, and FIG. 7 shows the relationship between the temperature of the sample stage and the volume resistivity for each amount of TiO□ added. As is clear from FIGS. 6 and 7, the volume resistivity decreases as the amount of added TiO2 increases and the temperature of the sample stage increases, and this relationship shows that the amount of added TiO2 increases. This shows that the volume resistivity can be easily controlled by changing the volume resistivity. Although the results shown in FIGS. 6 and 7 were obtained by using the plasma spraying method and varying the TiO2 mixing ratio, the same tendency can be seen in the results obtained by the sintering method.

Furthermore, the inventors have discovered that Al2O. A sample stage was prepared by covering a conductor with an insulating film containing TiO2, a sample was adsorbed onto the sample stage, and the sample was irradiated with plasma to examine the change in sample temperature over time, and the electrostatic adsorption force was investigated. evaluated. That is,
The thin film forming process and the etching process are normally performed in a high temperature atmosphere, and a coolant is circulated through the sample holding device to cool the sample. Therefore, when the electrostatic adsorption force is strong, the sample temperature approaches the refrigerant temperature, so by measuring the temporal change in the sample temperature, the response characteristics of the strength of the electrostatic adsorption force can be evaluated.

Figures 8(a) to (c) show Ti for AJ2□O,
This figure shows the change in sample temperature over time when the sample was irradiated with plasma while varying the Oz content and the sample stage was cooled and maintained at about 20°C.

Figure 8(a) contains 5wt% TiO□, Figure 8(b) contains 10wt% TiOz, and Figure 5(c) contains 15wt% TiO2. Each case is shown.

When the content of T i Oz is 5 wt% (Figure 8 (a)
), because the cooling effect of the refrigerant is insufficient, after starting plasma irradiation (plasma rONJ),
The sample temperature rises rapidly, and even after a sufficient period of time has passed, the sample temperature remains higher than when the voltage is "ON". That is, when the content of Ti0z is 5 wt%, the content of T s 02 is too small, so the volume resistivity is high and the response characteristics are poor, and as a result, it is considered that the electrostatic adsorption force is weak.

On the other hand, when the content of TiO Tested by the cooling effect of refrigerant! 4. The temperature hardly changed, and it is thought that the electrostatic adsorption force was enhanced and the sample was well adsorbed on the sample stage.

On the other hand, when there is no residual adsorption force, if the voltage applied to the sample stage is set to roFFJ, the influence of the cooling effect of the refrigerant will be reduced, and the sample temperature will rise rapidly. Therefore, when we investigated the change in sample temperature over time when the voltage was rOFFJ, we obtained measurement results as shown in FIGS. 9(a) to 9(C). Figure 9 (a) is 5w
t% TiO□ is contained, and FIG. 9(b) contains 10wt%
of T i Oz is contained, and FIG. 9(c) shows 15 wt%
The cases in which T i O2 of T i O2 are contained are respectively shown.

When the content of TiOz is 5 wt% (FIG. 9(a)), the sample temperature rises slowly, and it is considered that a considerable amount of residual adsorption force exists.

On the other hand, the content of T i O2 is 10 wt% (9th
(b)) and 15wt% (Fig. 9(c)), the sample temperature rises rapidly when the voltage is roFFJ6. In other words, when the TiO2 content is 10wt% and 15wt%, It is thought that by setting the voltage to roFFJ, there is almost no residual adsorption force to the sample.

For the above reasons, when the sample stage is held at around 20°C (the temperature of the insulating film is slightly higher than 20°C), it is necessary to make the insulating film contain 10 wt% or more of TiO2. The volume resistivity of the insulating film is 101 from
It is clear that by adjusting the resistance to 1 Ω·Cm or less, a sample holding device with large electrostatic adsorption force and almost no residual adsorption force (excellent response characteristics) can be obtained.

Also, when the volume resistivity of the insulating film is 1011Ω・cm, the time to reach the saturation adsorption force is as follows:
It is about 1/10 of 2Ω・am, and if the volume resistivity is 1olΩ・Cm, high response characteristics can be obtained.
As a result, a sample holding device with large electrostatic adsorption force and almost no residual adsorption force can be obtained.

However, in the equivalent circuit shown in Figure 5, in order to obtain high response characteristics, it is sufficient to reduce the resistance R as much as possible, but in an actual electrostatic chuck, the content of T i Ox is increased. The volume resistivity of the insulating film decreases, but
At the same time, the dielectric strength deteriorates, and dielectric breakdown is likely to occur even at low voltages. Furthermore, since leakage current increases, dielectric breakdown may occur in elements in the manufacture of semiconductor integrated circuits, which may reduce product yield. Therefore, the lower limit value of the volume resistivity of the insulating film must be selected in consideration of the above-mentioned matters.

Table 1 shows the experimental results of the dielectric breakdown test. That is, the content of TiO□ is changed and the temperature of the sample stage is cooled and maintained at about 20°C! , :2kV
, 1 kV, and 0.5 kV (7) voltages were applied for 1 minute, respectively, to evaluate the dielectric strength voltage. Each experiment was performed three times. The numbers in the table indicate the passing rate.

Table 1 Generally, the voltage applied to the sample stage is set at 300V to 800V, but as is clear from Table 2, dielectric breakdown occurs when the temperature of the sample stage is raised to about 20°C. In order to create a stable sample stand that will not cause
The content of 0g is preferably 20wt% or less. From the above results and Figure 6, the volume resistivity of the insulating film is 1
If the resistance is adjusted to 0.9 Ω·cm or more, a sample holding device that does not cause dielectric breakdown can be obtained. Note that when the volume resistivity of the insulating film is 10 9 Ω·cm, the time to reach saturation adsorption force is about several seconds at 20° C., and sufficiently high response characteristics can be obtained.

Furthermore, as shown in FIG. 7, /120. Since the volume resistivity of ceramics such as ceramics has the characteristic that it changes greatly depending on the temperature change of the sample stage, it is also necessary to select the amount of Ti0z added that is suitable for the set temperature in the semiconductor device manufacturing process. . For example, the temperature of the insulating film on the sample stage is about 150°C during film formation, and can be as low as minus several 10°C during etching. To be within the range, Aβ20. The amount of TiO□ added to
It is necessary to adjust the proportion to the required proportion below wt%.

For the above reasons, the insulating film contains T i O2 and 1
By adjusting the volume resistivity of the insulating film to be 10g to 10th Ωcm at operating temperatures of 00°C or lower, it exhibits high response characteristics, resulting in large electrostatic adsorption force and low residual resistance. A sample holding device that has almost no adsorption force can be obtained, and furthermore, a sample holding device that does not cause dielectric breakdown can be obtained.

Further, the insulating film has Ti0z of 25% for AI2□Os.
In the case where the insulating film has a volume resistivity of 10 g to 1011 Ω·cm, the electrostatic adsorption force is large and there is almost no residual adsorption force. First, a sample holding device that does not cause dielectric breakdown can be obtained.

Embodiments of the sample holding device according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an electrostatic chuck type sample holding device as an example of the sample holding device according to the present invention, and the sample holding device includes:
It consists of a sample stage 2 on which the sample 1 is placed, a cooling plate 3 for cooling the sample stage 2, a sample stage holder 4, and the like.

The sample stage 2 consists of a conductor 5 (electrode) formed of AJ2 and having a circular shape in plan view, coated with an insulating film 6, and this insulating film 6 is formed on the outer surface of the conductor 5 by a plasma spraying method. . That is, it contains Ti0z of 25 wt% or less, and 10
The volume resistivity of the insulating film 6 is 1 at an operating temperature of 0°C or lower.
A2゜0 adjusted to be 09~1011Ω・cm
．． Ceramic powder is melted at high temperature using plasma,
By spraying, an insulating film 6 is formed on the outer surface of the conductor 5. In this example, Aεgos: T
An insulating film 6 is formed with a composition ratio of i02 = 85wt%:15wt%6.Furthermore, a lead terminal 7 for voltage application is connected to the bottom surface of the conductor 5.

The cooling plate 3 has a cavity 8 formed so that a refrigerant such as water flows in the six directions of arrows and flows out in the direction of arrow B.
The sample stage 2 is configured to be cooled via a conductive sheet 9 made of n (indium) or the like.

The sample stage holder 4 is made of a metal material and has a locking part 4a on the upper part of its inner circumferential surface, and this locking part 4a holds the sample stage 2.
The cooling plate 3 is fixed to the cooling plate 3 via a fixing member 11 such as a screw.

The sample holding device is equipped with a sample removal mechanism 12, and as shown in FIG. 2(a), the sample stage 2 has an appropriate number of holes 1.
3... are provided through the conductive sheet 9 and the cooling plate 3.
Also, holes 14..., 15... correspond to the holes 13...
... is installed through it. The sample removal mechanism 12 is inserted into the holes 13..., 14..., 15.... That is, the sample removal mechanism 12 includes a flat ring member 16 with an appropriate number of bottles 17 protruding from the hole 1.
3..., 14..., 15....

Then, as shown in FIG. 2(b), the sample detachment mechanism 1
The sample 1 can be removed from the sample stage 2 by moving the sample 2 in the direction of arrow C.

When the sample holding device configured in this way is installed in a semiconductor device, for example, a plasma device, when the sample 1 is placed on the sample stage 2 and a voltage is applied to the lead terminal 7, the insulating film 6 is A capacitor having a constant capacitance is formed between the sample 1 and the conductor 5. That is, negative charges are accumulated on the back surface of the sample 1, while positive charges are accumulated on the conductor 5. Then, the sample l is adsorbed onto the surface of the sample stage 2, and the sample l is held on the sample stage 2.

Further, when the sample 1 is irradiated with plasma, negative charges are accumulated on the surface of the sample 1 due to the action of the plasma, and the sample 1 is more firmly adsorbed, thereby controlling the sample temperature to a constant temperature.

Table 2 shows the results of investigating the response characteristics of the electrostatic force of the sample holding device according to the present invention at an operating temperature of 20°C, and shows the results when an Aρ20n-TiOx ceramic material was used as the insulating film 6. The case is shown below. Also as a comparative example.

Insulating film 6 at a working temperature of 20°C without containing TiO2
For the case where the volume resistivity of is 1013Ω・cm, the second
Shown in the table.

Table 2 As is clear from Table 2, the volume resistivity of the insulating film 6 is 1.
B adjusted to be 09~1011Ω・cm
, C had a shorter time to reach saturation adsorption force than the device A, and the electrostatic force after 10 seconds of plasma irradiation was greater. Therefore, the volume resistivity of the insulating film 6 is 1011 to 10
It can be seen that by adjusting the resistance to 11 Ω·cm, it is possible to improve the responsiveness of electrostatic force.

Table 3 shows the results of investigating the electrostatic force response characteristics and electrostatic force of the sample holding device according to the present invention at an operating temperature of 80°C. As the insulating film 6, Aff, O
, contains 2.5 wt% T i Oz (B), 15
The case (C) is shown when wt% is included. Further, as a comparative example, a case (A) in which T i Ox is not included is also shown.

Table 3 In the case of Invention Example B, the volume resistivity at 20°C is 10
Although it exceeds 11 Ω·cm, the volume resistivity at the operating temperature of 80°C is 1011 Ω·cm, so the time to reach saturation adsorption force is shorter than that of A.

Table 4 shows the results of investigating the electrostatic force response characteristics and electrostatic force of the sample holding device according to the present invention at an operating temperature of 0°C.

Table 4 TiO□ was added to the insulating film 6 at 5wt% and 22.5% respectively.
wt%, and the volume resistivity at the operating temperature of 0°C is 10.
1' and 10' Ω·cm, devices B and C have a short time to reach saturation adsorption force. On the other hand, it contains 7.5 wt% of TiO2,
Device A, which has a volume resistivity of 1013 Ω·cm at an operating temperature of 0° C., takes a significantly long time to reach saturation adsorption force.

Figure 3 shows the refrigerant temperature Tc (°C) and the sample temperature T.

FIG. 3 is a characteristic diagram showing the relationship between In the figure, the square mark is the measured value.

Since the sample holding device according to the present invention has a strong electrostatic adsorption force, as is clear from this figure, the sample temperature Ts (℃
) is (refrigerant temperature TC + 15 degrees C))) By controlling the sample temperature to a predetermined temperature, a highly uniform thin film can be formed on the surface of the sample l. In the etching process, desired etching can be performed at a uniform etching rate.

FIGS. 4(a) to 4(C) show the relationship between sample temperature and etching state when sample 1 is etched.

Sample 1 has a Sin2 layer 19 formed on a wafer 18,
An Al2-Si alloy 20 and a 5iOz film 21 are formed on this SiO□ layer 19 layer table 9, and an Ae-Si alloy 20
A resist 22 is applied to the surface.

Figure 4(a) shows the case where etching is performed at the desired optimum temperature, Figure 4(b) shows the case where etching is performed at a temperature 20°C lower than the optimum temperature, and Figure 4(c) shows the case where etching is performed at a desired optimum temperature. 1 and 2 respectively show the case where etching was performed at a temperature 20° C. higher than the optimum temperature.

In FIG. 4(b), since the sample temperature Ts is low, S10□ film 2
4(c), the side wall of the Aff-Si alloy 20 is hollowed out due to the high sample temperature T. The smoothness is impaired (indicated by S in the figure). On the other hand, in the case of FIG. 4(a), the sample temperature T is controlled to the optimum temperature, so that the desired etching is achieved. In the present invention, since the sample is firmly adsorbed on the sample stage, the sample temperature can be controlled to the optimum temperature.
This is particularly effective in the etching process that requires stable and reproducible sample temperature control as described above.

Further, according to the sample holding device according to the present invention, when a predetermined thin film forming process or etching process is completed, plasma irradiation is stopped and the voltage to the sample stage 2 is set to rOFFJ, and then the sample 1F4 detachment mechanism 12 By moving the sample l in the direction of arrow C (see Fig. 2(b)), the sample l is placed on the sample stage 2.
It can be easily removed from the In the conventional sample holding device, there is a residual adsorption force, so when the sample detachment mechanism 12 is used, there is a risk that the sample l may be damaged or cracked.However, the sample holding device according to the present invention Since there is almost no residual adsorption force, the above sample removal mechanism 1
2 can be used to easily remove the sample 1 from the sample stage 2. In addition, when measuring the time taken for sample 1 to detach from sample stage 2, it was found that sample 1 could be detached easily in about 20 seconds after the voltage was turned off.
In Fig. 11 (see Fig. 11), the above-mentioned detachment time was required to be about 3 minutes, and it was confirmed that the residual adsorption force was reduced according to the present invention.

In addition, in the present invention, since the dielectric constant of the insulating film is high and the amount of charge is large, the conventional high voltage (500 to 800 V
) is no longer necessary, and sufficient electrostatic adsorption force can be obtained by applying a low voltage of 200 to 400 V.
It is possible to reduce the applied voltage.

In this example, the insulating film is made of Al2O3-TiO2.
Although we have explained the case where Si-based materials are used, for example, Si
C, carbides such as Si3N4, nitrides, SiO□, ZrO
It is also possible to use oxides such as □ and compounds thereof whose volume resistivity of the insulating film is adjusted to a range of 10 9 to 10 Ω·cm.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be modified without departing from the scope of the invention.

As is clear from the above description, in the sample holding device according to the present invention, a conductor is covered with an insulating film made of a ceramic material, and a voltage is applied between the sample and the conductor. In the sample holding device in which the sample is adsorbed onto the insulating film, the insulating film contains Ti1t, and the insulating film has a volume resistivity of 10' to 1011 at an operating temperature of 100°C or less.
Since it is adjusted to be Ω·cm, it is possible to realize an apparatus in which the electrostatic attraction force is enhanced, there is almost no residual attraction force, and the response characteristics of the electrostatic attraction force are high.

Therefore, the sample temperature can be easily controlled in semiconductor manufacturing equipment such as thin film forming equipment and etching equipment, a uniform thin film can be formed in the thin film forming process, and a uniform etching rate can be achieved in the etching process. Etching can be performed, and semiconductor devices with improved reliability can be manufactured.

Furthermore, since there is almost no residual adsorption force, even when removing the sample from the sample stage, the transfer arm for carrying the sample does not need to be equipped with a complex holding mechanism equipped with a grounding mechanism, which simplifies the apparatus. It is possible to aim for

In addition, since there is almost no residual adsorption force, the sample can be easily removed from the sample stage, making it possible to improve the reliability of the sample during transportation. It becomes possible to achieve this.

In addition, the insulating film has T i 02 of 2 for 8ρ203.
If it contains less than 5wt%,
The volume resistivity of the insulating film can be set within the range of 10' to 1011 Ωcm, the electrostatic adsorption force is large, there is almost no residual adsorption force, and furthermore, dielectric breakdown does not occur. A sample holding device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the sample holding device according to the present invention, FIGS. 2(a) and (b) are schematic sectional views showing the structure and operation of the sample removal mechanism, and FIG. 3 is the coolant temperature. Figures 4 (a) to (C) are perspective views of the sample showing the influence of sample temperature on etching, and Figure 5 shows the relationship between electrostatic chuck and sample temperature. The circuit diagram when it is used as a discharge circuit, Fig. 6 shows A I220 s and T i
TiO at each temperature of the sample stage when O2 is added
Graph showing the relationship between the amount of □ added and the volume resistivity, No. 7
The figure is a graph showing the relationship between sample stage temperature and volume resistivity for each addition amount of T i O2, and Figure 8 is a characteristic diagram showing the change in sample temperature over time after voltage and plasma
FIG. 9 is a characteristic diagram showing changes over time in voltage and sample temperature after plasma rOFFJ, and FIGS. 10 and 11 are sectional views showing essential parts of a conventional sample holding device. Fig. 1 1... Sample, 5... Conductor, 6... Insulating film. Patent applicant: Representative of Sumitomo Metal Industries, Ltd.
Person: Patent Attorney Ryuji Benuchi Figure 2 (a) (b) Figure 3 Figure 4 (a) (b) (C) Figure 8 Figure 9 Time Time■ Figure 6 Ti0z [Wj@7o1 10th Figure 11

Claims (2)

[Claims] (1) In a sample holding device in which a conductor is covered with an insulating film made of a ceramic material, a voltage is applied between a sample placed on the conductor and the conductor, and the sample is attracted onto the insulating film. , the insulating film contains TiO_2, and the volume resistivity of the insulating film is 10^ at an operating temperature of 100°C or less.
A sample holding device characterized by being adjusted to have a resistance of 9 to 10^1^1 Ω·cm. (2) In a sample holding device in which a conductor is covered with an insulating film made of a ceramic material, a voltage is applied between a sample placed on the conductor and the conductor, and the sample is attracted onto the insulating film. , the insulating film is TiO to Al_2O_3.
A sample holding device comprising _2 in a proportion of 25 wt% or less.