HEAT TREATMENT METHOD AND HEAT TREATMENT APPARATUS FOR HEATING SUBSTRATE BY IRRADIATING SUBSTRATE WITH LIGHT

• US 20120244725A1
• Filed: 03/12/2012
• Published: 09/27/2012
• Est. Priority Date: 03/23/2011
• Status: Active Grant

• Current Assignee: SCREEN Holdings Co., Ltd.
• Original Assignee: SCREEN Holdings Co., Ltd.
• Inventors: YOKOUCHI, Kenichi, FUSE, Kazuhiko, KATO, Shinichi
• Granted Patent: US 9,343,313 B2
• Time in Patent Office: Days
• US Class Current: 438/799
• CPC Class Codes: F27B 17/0025 Especially adapted for treating semiconductor wafers
• CPC Class Codes: H01L 21/02694 Controlling the interface between substrate and epitaxial layer, e.g. by ion implantation followed by annealing
• CPC Class Codes: H01L 21/2253 by ion implantation
• CPC Class Codes: H01L 21/26513 of electrically active species
• CPC Class Codes: H01L 21/2686 using incoherent radiation
• CPC Class Codes: H01L 21/324 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/20 - H01L21/288 and H01L21/302 - H01L21/322 take precedence
• CPC Class Codes: H01L 21/67115 mainly by radiation
• CPC Class Codes: H01L 21/67248 Temperature monitoring
• CPC Class Codes: H01L 21/68707 the wafers being placed on a robot blade, or gripped by a gripper for conveyance
• CPC Class Codes: H01L 21/68742 characterised by a lifting arrangement, e.g. lift pins

Abstract

First irradiation which causes an emission output from a flash lamp to reach its maximum value over a time period in the range of 1 to 20 milliseconds is performed to increase the temperature of a front surface of a semiconductor wafer from a preheating temperature to a target temperature for a time period in the range of 1 to 20 milliseconds. This achieves the activation of the impurities. Subsequently, second irradiation which gradually decreases the emission output from the maximum value over a time period in the range of 3 to 50 milliseconds is performed to maintain the temperature of the front surface within a ±25° C. range around the target temperature for a time period in the range of 3 to 50 milliseconds. This prevents the occurrence of process-induced damage while suppressing the diffusion of the impurities.

Claims

1. A method of heating a substrate by irradiating the substrate with light, to thereby activate impurities, the method comprising the steps of:

(a) heating a substrate to a predetermined preheating temperature;

(b) irradiating said substrate with light to increase the temperature of a front surface of said substrate from said preheating temperature to a target temperature for a time period in the range of 1 to 20 milliseconds; and

(c) irradiating said substrate with light to maintain the temperature of the front surface of said substrate within a ±

25°

C. range around said target temperature for a time period in the range of 3 to 50 milliseconds, said step (c) being performed after said step (b).

2. The method according to claim 1, wherein

said preheating temperature is in the range of 300°

to 800°

C., and

said target temperature is in the range of 1000°

to 1400°

C.

3. The method according to claim 1, wherein

said substrate is irradiated with a flash of light from a flash lamp in said step (b) and in said step (c).

4. The method according to claim 3, wherein

a switching element intermittently supplies electrical charges from a capacitor to said flash lamp to control an emission output from said flash lamp in said step (b) and in said step (c).

5. A heat treatment apparatus for heating a substrate by irradiating the substrate with light, to thereby activate impurities, the heat treatment apparatus comprising:

a chamber for receiving a substrate therein;

a holder for holding the substrate within said chamber;

a preheating part for heating the substrate held by said holder to a predetermined preheating temperature;

an irradiating part for irradiating the substrate held by said holder with light; and

a light emission controller for controlling an emission output from said irradiating part, said light emission controller being configured to control the emission output from said irradiating part so that the irradiating part irradiates the substrate held by said holder with light to increase the temperature of a front surface of said substrate from said preheating temperature to a target temperature for a time period in the range of 1 to 20 milliseconds and thereafter to maintain the temperature of the front surface of said substrate within a ±

25°

C. range around said target temperature for a time period in the range of 3 to 50 milliseconds.

6. The heat treatment apparatus according to claim 5, wherein

said preheating temperature is in the range of 300°

to 800°

C., and

said target temperature is in the range of 1000°

to 1400°

C.

7. The heat treatment apparatus according to claim 5, wherein

said irradiating part includes a flash lamp for emitting a flash of light.

8. The heat treatment apparatus according to claim 7, wherein

said light emission controller includes a switching element for intermittently supplying electrical charges from a capacitor to said flash lamp to control an emission output from said flash lamp.

9. A method of heating a substrate by irradiating the substrate with light, the method comprising the steps of:

(a) increasing an emission output from a flash lamp from zero to a first emission output value over a time period in the range of 1 to 20 milliseconds to irradiate a substrate with light; and

(b) irradiating the substrate with light while gradually decreasing the emission output from said flash lamp from the first emission output value over a time period in the range of 3 to 50 milliseconds so that the temperature of a front surface of said substrate is maintained within a ±

25°

C. range around a temperature reached by the front surface of the substrate in said step (a).

10. The method according to claim 9, wherein

a switching element intermittently supplies electrical charges from a capacitor to said flash lamp to control a current flowing to said flash lamp, thereby controlling the emission output.

11. The method according to claim 10, wherein

the electrical charges are intermittently supplied from said capacitor to said flash lamp by applying a plurality of pulses to the gate of said switching element.

12. The method according to claim 10, wherein

said switching element is an insulated-gate bipolar transistor.

13. A heat treatment apparatus for heating a substrate by irradiating the substrate with light, the heat treatment apparatus comprising:

a chamber for receiving a substrate therein;

a holder for holding the substrate within said chamber;

a flash lamp for irradiating the substrate held by said holder with light; and

a light emission controller for controlling an emission output from said flash lamp, said light emission controller being configured to control the emission output from said flash lamp so that the emission output is increased from zero to a first emission output value over a time period in the range of 1 to 20 milliseconds whereby the substrate is irradiated with light, and thereafter so that the substrate is irradiated with light while the emission output is gradually decreased from the first emission output value over a time period in the range of 3 to 50 milliseconds so that the temperature of a front surface of said substrate is maintained within a ±

25°

C. range around a temperature reached by the front surface of the substrate subjected to the former irradiation.

14. The heat treatment apparatus according to claim 13, wherein

said light emission controller includes a switching element for intermittently supplying electrical charges from a capacitor to said flash lamp to control a current flowing to said flash lamp, thereby controlling the emission output.

15. The heat treatment apparatus according to claim 14, wherein

said light emission controller includes a pulse applying part for applying a plurality of pulses to the gate of said switching element to intermittently supply the electrical charges from said capacitor to said flash lamp.

16. The heat treatment apparatus according to claim 14, wherein

said switching element is an insulated-gate bipolar transistor.

17. A method of heating a substrate by irradiating the substrate with light, the method comprising the steps of:

(a) heating a substrate to a predetermined preheating temperature;

(b) irradiating a first surface of said substrate with a flash of light from a flash lamp to increase the temperature of said first surface of said substrate from said preheating temperature to a target temperature over a time period longer than the time required for heat conduction from said first surface to a second surface of said substrate which is a surface opposite from said first surface; and

(c) irradiating said first surface of said substrate with a flash of light from said flash lamp to maintain the temperature of said first surface of said substrate within a ±

25°

C. range around said target temperature for not less than 5 milliseconds, said step (c) being performed after said step (b).

18. The method according to claim 17, wherein

the rate of increase in the temperature of said first surface in said step (b) is not less than 1000°

C./sec.

19. The method according to claim 17, wherein

said substrate is a semiconductor wafer of silicon.

20. The method according to claim 17, wherein

a switching element intermittently supplies electrical charges from a capacitor to said flash lamp to control an emission output from said flash lamp in said step (b) and in said step (c).

21. A heat treatment apparatus for heating a substrate by irradiating the substrate with light, the heat treatment apparatus comprising:

a chamber for receiving a substrate therein;

a holder for holding the substrate within said chamber;

a preheating part for heating the substrate held by said holder to a predetermined preheating temperature;

a flash lamp for irradiating the substrate held by said holder with a flash of light; and

a light emission controller for controlling an emission output from said flash lamp, said light emission controller being configured to control the emission output from said flash lamp so that the flash lamp irradiates a first surface of said substrate held by said holder with a flash of light to increase the temperature of said first surface of said substrate from said preheating temperature to a target temperature over a time period longer than the time required for heat conduction from said first surface to a second surface of said substrate which is a surface opposite from said first surface, and thereafter to maintain the temperature of said first surface of said substrate within a ±

25°

C. range around said target temperature for not less than 5 milliseconds.

22. The heat treatment apparatus according to claim 21, wherein

said light emission controller is configured to control the emission output from said flash lamp so that the temperature of said first surface is increased from said preheating temperature to said target temperature at a rate of not less than 1000°

C./sec.

23. The heat treatment apparatus according to claim 21, wherein

said substrate is a semiconductor wafer of silicon.

24. The heat treatment apparatus according to claim 21, wherein

said light emission controller includes a switching element for intermittently supplying electrical charges from a capacitor to said flash lamp to control the emission output from said flash lamp.