JP6422372B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus.

  Patent Document 1 below discloses a laser processing apparatus capable of suppressing window dirt. In this laser processing apparatus, a laser beam is introduced into a chamber through a window, and the laser beam is incident on a substrate. The gas introduced into the chamber from the gas outlet pipe is sprayed onto the substrate facing the window. The gas blown to the substrate is sucked through the gas suction tube.

JP 2006-253285 A

  Since the gas is blown onto the substrate facing the window, it is possible to prevent particles scattered from the substrate during laser annealing from adhering to the window. Part of the particles scattered from the substrate is discharged out of the chamber through the gas suction tube. However, particles that have not been discharged through the gas suction tube are scattered in the chamber and adhere to the inner wall of the chamber.

  The objective of this invention is providing the laser processing apparatus which can suppress the contamination in a chamber.

According to one aspect of the invention,
A chamber;
A table disposed in the chamber and holding a workpiece on an upper surface;
A laser introduction window provided at a position of the chamber facing the table;
A laser optical system for introducing a laser beam into the chamber through the laser introduction window;
A partition wall that separates a region sandwiched between the table and the laser introduction window from other regions in the chamber and defines an isolation space;
A descending airflow generating mechanism for generating a downward airflow from the laser introduction window toward the table in the isolation space ;
There is provided a laser processing apparatus having an elevating mechanism for elevating the partition .

  Since the region sandwiched between the table and the laser introduction window is isolated by the partition wall, it is possible to suppress the particles scattered from the object to be processed from being scattered outside the isolation space. Thereby, the contamination in the chamber is suppressed.

FIG. 1 is a schematic sectional view of a laser processing apparatus according to an embodiment. FIG. 2A is a plan view of the gas supply path and the gas outlet, and FIG. 2B is a plan view of the table. FIG. 3A is a partial cross-sectional view of a laser processing apparatus according to another embodiment, and FIG. 3B is a partial cross-sectional view showing a positional relationship between a partition wall and a table during laser processing. FIG. 4A is a partial cross-sectional view of a laser processing apparatus according to still another embodiment, and FIG. 4B is a partial cross-sectional view showing a positional relationship between a partition wall and a table during laser processing. FIG. 5 is a partial cross-sectional view of a laser processing apparatus according to still another embodiment. FIG. 6 is a partial cross-sectional view of a laser processing apparatus according to still another embodiment.

  FIG. 1 is a schematic sectional view of a laser processing apparatus according to an embodiment. A table 11 is disposed in the chamber 10. A workpiece 30 is held on the upper surface of the table 11. The workpiece 30 is fixed to the table 11 by, for example, a vacuum chuck. The lifting mechanism 12 moves the table 11 up and down.

  A laser introduction window 15 is provided at a position of the chamber 10 facing the table 11 (above the table 11). The laser optical system 40 outputs a laser beam. As a light source of the laser optical system 40, for example, a solid-state laser such as an Nd: YAG laser, or a gas laser such as a carbon dioxide gas laser or an excimer laser is used. The laser optical system 40 includes a variable attenuator, a beam expander, a beam section shaper (mask), a beam scanner (for example, a galvano scanner), a condenser lens, and the like arranged on the laser beam path.

  The laser beam output from the laser optical system 40 is introduced into the chamber 10 through the laser introduction window 15. The laser beam introduced into the chamber 10 enters the workpiece 30 held on the table 11. Thereby, laser processing is performed. Laser processing includes annealing for forming a refractory metal silicide film on the surface of a semiconductor wafer, activation annealing for activating ion-implanted dopant, crystallization annealing for crystallizing amorphous silicon, and the like. included.

  The partition wall 20 defines the isolation space 17 by isolating the space between the laser introduction window 15 and the table 11 from the other space 18 in the chamber 10. The partition wall 20 is made of, for example, a cylindrical aluminum member. The upper end of the partition wall 20 is in contact with the inner surface of the ceiling of the chamber 10. The laser beam introduced into the chamber 10 through the laser introduction window 15 passes through the isolation space 17 and reaches the workpiece 30.

  A descending airflow generating mechanism generates a descending airflow in the isolation space 17. The descending airflow generation mechanism includes a gas introduction mechanism and a gas suction mechanism. A gas introduction mechanism introduces gas into the isolation space 17. The gas introduction mechanism includes an on-off valve 21, a gas supply path 22, and a gas outlet 23. Gas is transported to the gas outlet 23 through the on-off valve 21 and the gas supply path 22. The gas outlet 23 is disposed in the vicinity of the upper end of the partition wall 20 and has an opening inside the partition wall 20. The gas transported to the gas ejection port 23 is ejected from the gas ejection port 23 into the isolation space 17.

  The gas suction mechanism sucks the gas in the isolation space 17 at a position lower than the position where the gas is introduced into the isolation space 17 by the gas introduction mechanism. The gas suction mechanism includes a gas suction port 24, a gas suction path 25, and an exhaust pump 26. The gas suction port 24 opens on the upper surface of the table 11. A part of the gas suction path 25 is provided in the table 11. The gas suction path 25 is connected to an exhaust pump 26 disposed outside the chamber 10. The exhaust pump 26 sucks the gas in the isolation space 17 through the gas suction port 24 and the gas suction path 25. A gas is ejected from a gas outlet 23 disposed relatively above the isolation space 17, and a gas is sucked from a gas suction port 24 disposed relatively below, so that a downdraft is generated in the isolation space 17. Will occur.

  The control device 45 controls the laser optical system 40, the on-off valve 21, the exhaust pump 26, and the lifting mechanism 12. The control device 45 controls the elevating mechanism 12 so that the upper surface of the workpiece 30 is arranged at a target height according to the thickness of the workpiece 30. By arranging the upper surface of the workpiece 30 at a target height, the profile of the laser beam on the upper surface of the workpiece 30 can be maintained in a suitable shape. A minute gap is generated between the upper surface of the table 11 and the lower end of the partition wall 20 in a state where the upper surface of the workpiece 30 is arranged at a target height.

  The chamber 10 has a gas introduction port 13 and a gas exhaust port 14. Gas is introduced into the chamber 10 from the gas inlet 13 and gas is exhausted from the gas outlet 14. The gas introduced from the gas inlet 13 and the gas supplied through the gas supply path 22 are the same. As this gas, for example, an inert gas such as nitrogen gas or argon gas is used.

  FIG. 2A shows a plan view of the gas supply path 22 and the gas outlet 23. The gas supply path 22 includes an annular portion 22 a that surrounds the partition wall 20. A plurality of gas outlets 23 extend inward from the annular portion 22 a, penetrate the partition wall 20, and open to the isolation space 17. The plurality of gas ejection ports 23 are arranged at positions that are rotationally symmetric with respect to the central axis of the isolation space 17. Gas is ejected from the gas ejection port 23 toward the central axis of the isolation space 17.

  FIG. 2B shows a plan view of the table 11. A workpiece 30 is held on the upper surface of the table 11. The upper surface of the table 11 is wider than the workpiece 30. The gas suction port 24 opens in a region outside the outer periphery of the workpiece 30 on the upper surface of the table 11. The gas suction port 24 has an annular plane shape surrounding the workpiece 30. The gas suction port 24 is disposed inside the partition wall 20 (FIG. 2A) in plan view. A part of the gas suction path 25 is provided inside the table 11 along the gas suction port 24.

  In the above-described embodiment, as shown in FIG. 1, since a descending airflow is generated in the isolation space 17, particles scattered from the workpiece 30 do not easily reach the laser introduction window 15. For this reason, the contamination of the laser introduction window 15 due to the adhesion of particles can be suppressed.

  Most of the scattered particles are sucked together with the gas from the gas suction port 24. Further, the isolation space 17 is isolated from the other space 18 in the chamber 10 by the partition wall 20. For this reason, scattering of particles up to the space 18 outside the isolation space 17 is prevented. Thereby, the stain | pollution | contamination of the inner surface of the chamber 10 is suppressed.

  In order to prevent particles from scattering up to the space 18, it is preferable to make the gap between the upper surface of the table 11 and the lower end of the partition wall 20 as narrow as possible. As an example, it is preferable that the gap during laser processing is narrower than the thickness of the workpiece 30. In this case, the lower end of the partition wall 20 is lower than the upper surface of the workpiece 30.

  FIG. 3A shows a partial cross-sectional view of a laser processing apparatus according to another embodiment. Hereinafter, differences from the embodiment shown in FIGS. 1 to 2B will be described, and description of common configurations will be omitted.

  In the embodiment shown in FIG. 1, the partition wall 20 is fixed to the upper surface of the chamber 10. In the embodiment shown in FIG. 3A, the partition wall 20 is supported by the chamber 10 via the lifting mechanism 27. The elevating mechanism 27 elevates and lowers the partition wall 20 according to a command from the control device 45 (FIG. 1). In order to allow the partition wall 20 to move up and down, a part of the gas supply path 22 is formed of flexible piping. When the partition wall 20 is lowered, a gap is generated between the upper end of the partition wall 20 and the upper surface of the chamber 10.

  FIG. 3B shows the positional relationship between the partition wall 20 and the table 11 during laser processing. Before performing laser processing, the control device 45 controls the lifting mechanism 12 for the table 11 and arranges the upper surface of the workpiece 30 at a target height. Thereafter, the control device 45 controls the lifting mechanism 27 for the partition wall 20 to lower the partition wall 20. When the lower end of the partition wall 20 comes into contact with the upper surface of the table 11, the descent is stopped.

  In the embodiment shown in FIGS. 3A and 3B, no gap is generated between the lower end of the partition wall 20 and the upper surface of the table 11 during laser processing. For this reason, it is possible to enhance the effect of preventing particles scattered from the workpiece 30 from scattering to the outside of the isolation space 17. Although a gap is generated between the partition wall 20 and the upper surface of the chamber 10, since a descending airflow is generated in the isolation space 17, particles are hardly scattered from the upper end gap to the outside of the isolation space 17. .

  FIG. 4A shows a partial cross-sectional view of a laser processing apparatus according to still another embodiment. Hereinafter, differences from the embodiment shown in FIGS. 3A and 3B will be described, and descriptions of common configurations will be omitted.

  In the embodiment shown in FIG. 4A, a flexible member 28 is disposed between the upper end of the partition wall 20 and the upper surface of the chamber 10. The flexible member 28 allows the partition wall 20 to move up and down and closes the gap between the upper end of the partition wall 20 and the upper surface of the chamber 10. As the flexible member 28, for example, a bellows can be used.

  FIG. 4B shows the relative positional relationship between the partition wall 20 and the table 11 during laser processing. At the time of laser processing, the lower end of the partition wall 20 contacts the upper surface of the table 11 as in the embodiment shown in FIG. 3B. When the partition wall 20 is lowered, the flexible member 28 is deformed according to the enlargement of the gap. For this reason, the state where the gap between the upper end of the partition wall 20 and the upper surface of the chamber 10 is closed by the flexible member 28 is maintained. Since the gap is closed, the particles can be prevented from scattering from the isolation space 17 to the outside.

  FIG. 5 is a partial sectional view of a laser processing apparatus according to still another embodiment. Hereinafter, differences from the embodiment shown in FIGS. 3A and 3B will be described, and descriptions of common configurations will be omitted.

  In the embodiment shown in FIGS. 3A and 3B, the workpiece 30 is smaller than the region surrounded by the inner peripheral surface of the partition wall 20 in plan view. In the embodiment shown in FIG. 5, the workpiece 30 is larger than the region surrounded by the inner peripheral surface of the partition wall 20 in plan view. Of the upper surface of the table 11, the region surrounded by the inner peripheral surface of the partition wall 20 is covered with the workpiece 30. Since the upper surface of the table 11 is not exposed in the region surrounded by the inner peripheral surface of the partition wall 20, the gas cannot be sucked from the gas suction port disposed on the upper surface of the table 11.

  In the embodiment shown in FIG. 5, a gas suction port 24 is fixed to the partition wall 20. The gas suction port 24 is disposed below the gas ejection port 23. A gas suction port 24 is connected to an exhaust pump 26 via a gas suction path 25. A part of the gas suction path 25 is formed by flexible piping. As the gas in the isolation space 17 is sucked from the gas suction port 24, a downward air flow is generated in the isolation space 17. At the time of laser processing, a minute gap is secured between the upper surface of the workpiece 30 and the lower end of the partition wall 20.

  Since the gas suction port 24 is fixed to the partition wall 20, it is possible to process the workpiece 30 larger than the region surrounded by the inner peripheral surface of the partition wall 20.

  FIG. 6 shows a partial cross-sectional view of a laser processing apparatus according to still another embodiment. Hereinafter, differences from the embodiment shown in FIG. 5 will be described, and description of common configurations will be omitted.

  In the embodiment shown in FIG. 6, an elastic member 29 is attached to the lower end of the partition wall 20. As the elastic member 29, for example, sponge, rubber or the like is used. When the partition wall 20 is lowered, the elastic member 29 comes into contact with the workpiece 30. When further lowered, the elastic member 29 is elastically deformed according to the distance between the upper surface of the workpiece 30 and the lower end of the partition wall 20. For this reason, the gap between the upper surface of the workpiece 30 and the lower end of the partition wall 20 is closed by the elastic member 29 during laser processing.

  Since the gap between the upper surface of the workpiece 30 and the lower end of the partition wall 20 is closed, particles scattered from the workpiece 30 can be prevented from scattering to the outside of the isolation space 17. By using a sufficiently soft material as the elastic member 29, it is possible to prevent damage to the workpiece 30 due to the elastic member 29 coming into contact with the workpiece 30.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Chamber 11 Table 12 Elevating mechanism 13 Gas introduction port 14 Gas exhaust port 15 Laser introduction window 17 Isolation space 18 Other space 20 in chamber 20 Partition 21 Opening / closing valve 22 Gas supply path 22a Gas supply path annular part 23 Gas jet 24 Gas suction port 25 Gas suction path 26 Exhaust pump 27 Elevating mechanism 28 Flexible member 29 Elastic member 30 Work object 40 Laser optical system 45 Control device

Claims (4)

A chamber;
A table disposed in the chamber and holding a workpiece on an upper surface;
A laser introduction window provided at a position of the chamber facing the table;
A laser optical system for introducing a laser beam into the chamber through the laser introduction window;
A partition wall that separates a region sandwiched between the table and the laser introduction window from other regions in the chamber and defines an isolation space;
A descending airflow generating mechanism for generating a downward airflow from the laser introduction window toward the table in the isolation space ;
A laser processing apparatus, comprising: an elevating mechanism for elevating and lowering the partition wall . The downdraft generation mechanism is
A gas introduction mechanism for introducing gas into the isolation space;
The laser processing apparatus according to claim 1 , further comprising: a gas suction mechanism that sucks gas in the isolation space at a position lower than a position where gas is introduced into the isolation space by the gas introduction mechanism. The laser processing apparatus according to claim 2 , wherein the gas suction mechanism includes a gas suction port that opens to an upper surface of the table. The laser processing apparatus according to claim 2 , wherein the gas suction mechanism includes a gas suction port that is attached to the partition wall and sucks a gas in the isolation space.

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