JPH06104200A - Heating apparatus for ion-implantation substrate - Google Patents

Abstract

PURPOSE:To provide a heating apparatus for an ion-implantation substrate with a small leak of an ion current when the ion reaches a wafer. CONSTITUTION:A heating apparatus for an ion-implantation substrate comprises a first member 3 made of a material with high electrical and thermal conductivity, a second member 4 provided closely under the first member 3 and made of a material with high insulation even at high temperatures, and a third member 5 provided closely under the second member 4 and included in a heater block. The second member 4 has a thermocouple 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when a semiconductor substrate is implanted at a temperature higher than room temperature, is accurately monitored without fluctuation of ion current value due to leak current and without noise current amplitude. The present invention relates to a substrate heating device for ion implantation that can be performed.

[0002]

2. Description of the Related Art FIGS. 3 (a) and 3 (b) show a schematic view of a substrate heating apparatus and a schematic view of a heater power supply unit according to the prior art. In the figure, 1 is a clamper, 2 is a wafer, 3
Is a first member, 4 is a second member, 5 is a third member, 6 is a thermocouple insertion hole, 7 is a thermocouple, 8 is a thermocouple insulating tube, 9 is an AC power input terminal, and 12 is a thermoelectric A pair signal input terminal, 13 is a heater power output terminal, 14 is a power input terminal, 15 is a temperature controller section, and 16 is a power controller section. Next, the operation will be described. For the ion current, a method was selected in which the ion beam reaching the wafer 2 set in the substrate heating unit was taken out from the clamper 1 and introduced into the current integrator. This is because the ion beam that has reached the wafer 2 can be directly measured and the configuration is simple. But,
Sufficient noise countermeasures are required. Thermocouple 7 is wafer 2
It is provided on the first member 3 in order to measure the temperature of the portion close to. An insulating material is used for the second member 4, and AC power is supplied to the heater block of the third member 5.
Here, when power is turned on to the temperature controller unit 15 and the power supply controller unit 16 in FIG. 3B and the device shown in the figure is actually operated, a part of the ion current leaks to the outside due to the resistance drop at a high temperature. In addition, various noises from the temperature controller unit 15 and the power supply controller unit 16 may flow into the current integrator. Generally, various methods are known as noise countermeasures, but each device needs its own countermeasures. Although conventional measures such as a line filter and an insulation transformer have been tried for the conventional device, the leak current and the noise current in the substrate heating device are about several nA to several 100 nA, and there is almost no change before and after these normal measures. Therefore, the number 1
If the implantation is performed with an ion current of 0 μA or less, an error of the percent order occurs and reproducibility cannot be obtained. It was also found that the noise contains a commercial power supply frequency component of 50 Hz. For these reasons, the conventional substrate heating device cannot accurately measure the ion current, and ion implantation with high reproducibility cannot be performed.

[0003]

SUMMARY OF THE INVENTION The present invention has been proposed in order to improve the above-mentioned drawbacks, and its purpose is to increase the temperature of the substrate heating portion to a high temperature and to perform ion implantation in a temperature-controlled state. An object of the present invention is to provide an ion implantation substrate heating apparatus capable of accurately monitoring an ion current reaching a wafer without leakage and eliminating noise currents from a temperature monitor system and a heater block system.

[0004]

In order to achieve the above-mentioned object, the present invention provides a first member made of a material having a high electric conductivity and a high thermal conductivity and a lower part of the first member in close contact with each other. A second member made of a material having a high insulating property even at a high temperature, and a third member that is provided in close contact with a lower portion of the second member and constitutes a heater block, and The gist of the invention is an ion implantation substrate heating device characterized in that a thermocouple is provided on the second member.

[0005]

According to the substrate heating apparatus for ion implantation of the present invention, by mounting the thermocouple inserted in the insulating tube in the second member that maintains high insulation resistance even at high temperature,
Even when the temperature is raised to about 0 ° C., increase / decrease in current value and noise are not observed in the current range of 1 μA. Therefore, it has the effect that high temperature implantation can be performed with the same accuracy as the ion implantation current at room temperature.

[0006]

EXAMPLES Next, examples of the present invention will be described. Conventionally, Al ₂ O ₃ , SiO ₂ and BN have been used as highly insulating materials.
Various ceramic materials were used. Among these materials, even if the resistivity (ρ) near room temperature is as high as ρ> 10 ¹² Ωcm, it is ρ near 300 ° C.
Not less than 10 ¹¹ Ωcm. In the present invention, by using Al ₂ O ₃ having ρ of 10 ¹² Ωcm even at 300 ° C., the fluctuation of the ion current value due to the leak current is 20 nA in Example 1, which is 1/1 / the conventional value.
This is due to the fact that we have found that we can do about three. (Embodiment 1) FIG. 1A is a schematic view of a substrate holder portion of an ion implantation substrate heating apparatus according to the present invention. In the figure, 1 is a clamper, 2 is a wafer, 3 is a first member,
4 is a second member, 5 is a third member, 6 is a thermocouple insertion hole,
Reference numeral 7 is a thermocouple, 8 is a thermocouple insulating tube, and 9 is an AC power input terminal. The substrate holder has a three-layer structure. First, the first member 3 is made of carbon, and then the second member 4 is made of carbon.
Alumina, which has a good insulation temperature characteristic, was used for this. The third member 5 is a heater block. The wafer 2 was placed on the first member 3 and then fixed by the clamper 1. The ionic current was drawn from the clamper 1, introduced into a current integrator, and measured. The thermocouple 7 was sealed with an alumina insulating tube 8 and inserted into the second member 4 in order to reduce ion current leakage and noise. In this case, first the thermocouple is attached to the first member 3
However, the difference between the set temperature and the wafer surface temperature becomes a problem as compared with the case where it is inserted into the wafer. However, the wafer surface temperature 10 minutes after the temperature is raised to a certain set temperature and the wafer is mounted is 50 ° C.
It was confirmed to be low. This value is the same as when the thermocouple was inserted into the first member 3 and the same sequence was performed,
It was found that it can be used stably up to around 300 ° C. Figure 1
(B) is a schematic diagram of a heater power supply. In the figure,
Reference numeral 12 is a signal input terminal from the thermocouple, 13 is a heater power supply output terminal, 14 is a power supply input terminal, 15 is a temperature controller section, 16 is a power supply controller section, and 17 is a photocoupler. The temperature controller unit 15 and the power supply controller unit 16 are electrically insulated by a photo coupler 17. A signal obtained by comparing the output from the thermocouple with a preset temperature is input to the temperature controller unit and the power supply controller unit. The input of the power supply is 100V AC (single phase), but the power supply controller is AC-
A direct current exchange section was built in, and the output was a direct current of 70V, 15A. With such a configuration, it was confirmed that no noise including the 50 Hz commercial power source frequency component was observed at a current range of 1 μA even when the temperature was raised to about 300 ° C. Even when an ion current of several μA was actually drawn, an increase / decrease in current value and an injection waveform without noise were observed. FIG. 2A shows leakage current values when the thermocouple was attached, when the heater power was turned on, and when the heater was heated (300 ° C.), comparing the conventional example with the present invention. In the case of the conventional technique, a leak current value of about 40-60 nA was measured, but in the present invention (Example 1), it could be reduced to 10-20 nA. Similarly, the noise current amplitude was 5-20 nA in the case of the conventional technique, which was increased by turning on the heater power, but in the present technique, it is below the detection sensitivity. FIG. 2B shows the noise current amplitude.

(Embodiment 2) In the above-mentioned Embodiment 1, when a bimeter is inserted in place of the thermocouple in the first member 3 or the second member 4 and the temperature is controlled by this bimeter (Embodiment 2), The leak current value is reduced to 5 nA, and the noise current amplitude is below the detection sensitivity as in the case of the first embodiment.

[0008]

According to the present invention, a first member made of a material having a high electric conductivity and a high thermal conductivity and a lower portion of the first member are provided in close contact with each other, and have a high insulating property even at a high temperature. A second member made of a material having a: and a third member that is provided in close contact with the lower portion of the second member and that constitutes a heater block, and a thermocouple is provided on the second member. As a result, the ion current at the time of high temperature ion implantation can be measured with the same accuracy as at room temperature, which has the effect of realizing high temperature ion implantation with excellent controllability and reproducibility.

[Brief description of drawings]

1A and 1B show a substrate heating apparatus of the present invention, wherein FIG. 1A is a schematic view of the apparatus, and FIG. 1B is a schematic view of a heater power supply.

FIG. 2A shows a leak current value and FIG. 2B shows a noise current amplitude when the thermocouple is attached, when the heater power is turned on, and when the heater is heated.

3A and 3B show a conventional substrate heating apparatus, wherein FIG. 3A is a schematic view of the apparatus, and FIG. 3B is a schematic view of a heater power supply unit.

[Explanation of symbols]

 1 Clamper 2 Wafer 3 First Member 4 Second Member 5 Third Member 6 Thermocouple Insertion Hole 7 Thermocouple 8 Thermocouple Insulation Tube 9 DC Power Input Terminal 12 Thermocouple Signal Input Terminal 13 Heater Power Output Terminal 14 Power input terminal 15 Temperature controller 16 Power controller 17 Photocoupler

Claims (2)

[Claims] 1. A first member made of a material having a high electric conductivity and a high thermal conductivity, and a first member made of a material which is provided in close contact with a lower portion of the first member and has a high insulating property even at a high temperature. 2 and a third member which is provided in close contact with the lower part of the second member and constitutes a heater block, and the second member is provided with a thermocouple. Substrate heating device for injection. 2. The signal output side of the temperature controller section and the signal input side of the power supply controller section are electrically insulated from each other, and the output of the thermocouple is input to the temperature controller section and compared with the set temperature. 2. The ion implanting apparatus according to claim 1, further comprising: a unit that sends the signal obtained as a control signal to a power supply controller unit and a unit that supplies the power supply controller unit as a DC power to the heater block. Substrate heating device.