JP2003272551A - Ion implantation device and its wafer temperature control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion implantation device and its wafer temperature control method capable of controlling a generation amount of crystal defect by restraining temperature variation of a semiconductor wafer during ion implantation. <P>SOLUTION: This ion implantation device has an ion implantation chamber 103 provided with a support base 11 of the semiconductor wafer Waf. The support base 11 has a clamp ring 12 on its main surface side to hold the wafer Waf. A heater 13 for conducting heat to the back face side of the wafer Waf is embedded in the support base 11. A temperature sensor 14 is mounted there to sense the temperature of the support base 11 and thereby to control the drive of the heater 13. On the back face side of the support base 11, a radiant member 15 formed of a material different from that of the support base 11 is installed as a cooling mechanism. The temperature is sensed by the temperature sensor 14 while radiating the heat of the support base 11 by the radiant member 15, and the result thereof is fed back to control the drive of the heater 13. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implanter for implanting and controlling impurity ions that determine device characteristics in a semiconductor process, and more particularly to an ion implanter for managing a semiconductor wafer temperature for more accurate ion implanting. The present invention relates to the wafer temperature control method.

[0002]

2. Description of the Related Art In an ion implantation apparatus, target impurity ions are extracted from an ion beam by using mass spectrometry or the like, irradiated onto a semiconductor wafer, and implanted into a predetermined amount. The temperature rise of the wafer during the ion implantation is generally performed by supplying cooling water to the wafer holder and cooling by introducing gas between the wafer and the wafer holder. If the temperature rise of the wafer is left as it is, the wafer heats up and the adverse effects such as alteration (hardening) of the resist and crystal defects due to ion implantation damage are large. Therefore, it is necessary to suppress the temperature rise of the wafer during ion implantation.

It is known that the temperature change on the wafer surface during ion implantation affects the amount of crystal defects generated. The wafer surface changes depending on the density of the ion beam, but changes in the range of about 50 to 120 ° C.
If there is such a variation in wafer temperature, satisfactory data cannot be obtained even when inspecting the degree of influence of crystal defects due to temperature change. For that reason, it is desired to suppress the temperature rise of the wafer and further suppress the temperature change.

[0004]

In the past, cooling water or cooling gas was used to suppress the temperature change on the wafer surface during ion implantation, but either method is still insufficient from the viewpoint of wafer temperature control. The composition was not satisfactory. The wafer temperature easily changes due to changes in the ion beam current amount, current density, irradiation time, and the like. As a result, there is a problem that it is difficult to manage the defect detection and inspection process due to ion implantation damage.

The present invention has been made in consideration of the above circumstances, and provides an ion implantation apparatus and a wafer temperature control method thereof for suppressing a temperature change of a semiconductor wafer during ion implantation and controlling a crystal defect generation amount. It is the one we are trying to provide.

[0006]

An ion implanter according to the present invention is an ion implanter for irradiating a semiconductor wafer with predetermined impurity ions of an ion beam extracted from an ion source, which is mainly used in an ion implant chamber. A support for supporting the semiconductor wafer on the surface side, a heater embedded in the support for conducting heat to the back side of the semiconductor wafer, and a temperature sensor for sensing the temperature of the support and controlling the driving of the heater. And a cooling mechanism that is provided on the back surface side with respect to the main surface of the support table to promote heat dissipation.

According to the above-described ion implantation apparatus of the present invention, the semiconductor wafer support can be provided with a heater and a cooling mechanism to cope with quick temperature control. The temperature sensor controls the driving of the heater as needed.
This contributes to stabilizing the temperature of the wafer.

Further, in the ion implantation apparatus according to the present invention, the cooling mechanism includes a radiation member made of a material different from that of the support base. Further, the cooling mechanism includes a gas cooling mechanism accompanied by supply of a refrigerant gas. Thereby, during ion implantation, heat dissipation may be always promoted from the back surface side of the support base.

A method for controlling a wafer temperature of an ion implantation apparatus according to the present invention is such that when a semiconductor wafer is irradiated with impurity ions by an ion beam in the ion implantation apparatus, the temperature of a wafer supporting table which affects the temperature of the semiconductor wafer is raised. Mechanism and temperature lowering mechanism are respectively provided, the temperature is detected while the support table is radiated by the temperature lowering mechanism, and the result is fed back to drive and control the temperature raising mechanism to stabilize the temperature of the semiconductor wafer within a predetermined range. It is characterized by

According to the wafer temperature control method for the ion implantation apparatus of the present invention, the temperature lowering operation of the support is not always stopped at least during the ion implantation, and the temperature raising operation is performed delicately as needed by the sensor. . This stabilizes the temperature of the semiconductor wafer within a predetermined range. The temperature lowering mechanism is characterized by utilizing the supply or circulation of the refrigerant gas and the cooling action by radiation.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view showing a main structure of an ion implantation apparatus according to a first embodiment of the present invention. The ion implantation apparatus 100 has a mechanism that extends from the ion source unit 101 to the ion implantation chamber 103 via the beam line unit 102. The figure shows a device configuration of a large current machine as a representative, and a general detailed configuration other than the configuration according to the present invention is omitted.

Regarding the ion implantation chamber 103, a support base 11 for the semiconductor wafer Waf is provided. The support 11 has a clamp ring 12 on the main surface side and holds the wafer Waf. The support base 11 is installed in a Faraday (not shown) or is provided after the implantation mask having a beam collector such as a dose Faraday (not shown).

A heater 13 that conducts heat to the back side of the wafer Waf is embedded in the support base 11. Further, a temperature sensor 14 is provided to detect the temperature of the support base 11 and control the driving of the heater 13. Temperature sensor 14
Is an S having a thermocouple embedded in the support 11, for example.
It is composed of an i-chip.

Further, a radiation member 15 made of a material different from that of the support base 11 is provided on the back side of the support base 11 as a cooling mechanism. If the support base 11 is made of, for example, stainless steel (SUS), the radiation member 15 is made of, for example, fine wires and a blackbody radiation material (carbon or the like). Thereby, the radiant heat from the support base 11 is absorbed and radiated.

According to the above-described embodiment, the semiconductor wafer supporting base 11 is provided with the heater 13 and the radiating member 15 to cope with the rapid temperature control. Temperature sensor 14
Thus, the driving of the heater 13 is controlled as necessary.
This contributes to stabilizing the temperature of the wafer.

Hereinafter, such a wafer temperature control method will be described. When the semiconductor wafer Waf is irradiated with the impurity ions by the ion implantation apparatus 100, the wafer Waf
The support member 11 that affects the temperature is radiated by the radiation member 15. At the same time, the temperature is detected by the temperature sensor 14, and the result is fed back to control the driving of the heater 13. This stabilizes the temperature of the semiconductor wafer Waf during the ion implantation within a predetermined range.

FIG. 2 is a schematic view showing the structure of the main part of an ion implantation apparatus according to the second embodiment of the present invention, showing a support base for semiconductor wafers. The same parts as those in FIG. The difference from the first embodiment is that
The point is that a gas cooling mechanism 16 for supplying a refrigerant gas is provided instead of the radiation member 15 as a cooling mechanism. Argon gas, for example, is used as the refrigerant gas. Thereby, the radiant heat from the support base 11 is radiated.

The same effects as those of the first embodiment can be obtained by the above embodiment. That is, during the ion implantation, the support table 11 that influences the temperature of the wafer Waf is radiated by the supply (16) of the refrigerant gas. At the same time, the temperature is detected by the temperature sensor 14, and the result is fed back to control the driving of the heater 13. This stabilizes the temperature of the semiconductor wafer Waf during the ion implantation within a predetermined range.

FIG. 3 is a schematic view showing the structure of the main part of an ion implantation apparatus according to the third embodiment of the present invention, showing a support base for semiconductor wafers. The same parts as those in FIGS. 1 and 2 are designated by the same reference numerals and the description thereof will be omitted. A cooling mechanism having both the first and second embodiments is configured. As shown in the figure, a radiation member 15 and a gas cooling mechanism 16 for the radiation member 15 are provided. The refrigerant gas is, for example, argon gas. Thereby, the radiant heat from the support base 11 is radiated.

The same effects as those of the first embodiment can be obtained by the above embodiment. That is, during ion implantation, the support base 11 that affects the temperature of the wafer Waf is attached to the radiation member 1.
The heat is dissipated by supplying (5) and the refrigerant gas (16). The supply of the refrigerant gas may be appropriately controlled. At the same time, the temperature is detected by the temperature sensor 14, and the result is fed back to control the driving of the heater 13.
This stabilizes the temperature of the semiconductor wafer Waf during the ion implantation within a predetermined range.

According to the above embodiments and wafer temperature control method, the wafer temperature during the ion implantation process is, for example, 50.
It is possible to perform stabilization control within a range of smaller temperature changes such as ˜55 ° C. The amount of crystal defects generated during ion implantation varies depending on the wafer temperature. Therefore, with the above configuration, it can be expected that the generation of crystal defects can be accurately controlled in the inspection process that uses the non-contact type crystal defect inspection device later.

[0022]

As described above, according to the present invention,
The semiconductor wafer support can be provided with a heater and a cooling mechanism to cope with quick temperature control. The temperature sensor controls the driving of the heater as needed. This contributes to the stabilization of the temperature of the wafer, and can be expected to allow accurate control of the generation of crystal defects. As a result, it is possible to provide an ion implantation apparatus and a wafer temperature control method thereof that suppress the temperature change of a semiconductor wafer during ion implantation and control the amount of crystal defects generated.

[Brief description of drawings]

FIG. 1 is a schematic view showing a configuration of a main part of an ion implantation device according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing a configuration of a main part of an ion implantation apparatus according to a second embodiment of the present invention, showing a support base for a semiconductor wafer.

FIG. 3 is a schematic view showing a main configuration of an ion implantation apparatus according to a third embodiment of the present invention, showing a support base for a semiconductor wafer.

[Explanation of symbols]

100 ... Ion implanter 101 ... Ion source part 102 ... Beam line section 103 ... Ion implantation chamber 11 ... Support stand 12 ... Clamp ring 13 ... Heater 14 ... Temperature sensor 15 ... Radiant member 16 ... Gas cooling mechanism Waf ... Semiconductor wafer

Claims (5)

[Claims] 1. An ion implanter for irradiating a semiconductor wafer with predetermined impurity ions of an ion beam extracted from an ion source, comprising: a support base for supporting the semiconductor wafer on a main surface side in an ion implantation chamber. A heater embedded in the support table for conducting heat to the back surface of the semiconductor wafer; a temperature sensor for sensing the temperature of the support table to control the driving of the heater; and a heater provided on the back surface side of the main surface of the support table An ion implantation apparatus comprising: a cooling mechanism that promotes heat dissipation. 2. The ion implantation apparatus according to claim 1, wherein the cooling mechanism includes a radiation member made of a material different from that of the support base. 3. The cooling mechanism according to claim 1, wherein the cooling mechanism includes a gas cooling mechanism accompanied by supply of a refrigerant gas.
The ion implanter described. 4. When irradiating a semiconductor wafer with impurity ions by an ion beam in an ion implantation apparatus, a temperature raising mechanism and a temperature lowering mechanism of a wafer support table that affect the temperature of the semiconductor wafer are respectively provided, and the support table is provided. Wafer temperature control of an ion implantation apparatus, characterized in that the temperature is detected by the temperature lowering mechanism while the temperature is detected, and the result is fed back to control the temperature raising mechanism to stabilize the temperature of the semiconductor wafer within a predetermined range. Method. 5. The method for controlling a wafer temperature of an ion implantation apparatus according to claim 4, wherein the temperature lowering mechanism uses a cooling action by supplying or circulating a refrigerant gas or radiation.