JP2012224921A - Film forming apparatus - Google Patents

Abstract

Dispersion of particles in a chamber is suppressed by making it difficult for a deposit deposited on a deposition plate by sputtering to be peeled off even when stress is applied during expansion and contraction.
A lower protection plate 17 is configured by a flat surface 31 from an inner peripheral edge 17c where the upper surface side 17a facing the target is close to a stage 13 to a position overlapping at least a lower end 16E of the upper protection plate. ing. Such a flat surface 31 may be, for example, an inclined surface that spreads from the inner peripheral edge 17 c toward the inner peripheral surface (side wall) 11 a of the chamber 11 within an angle θ of 5 ° to 20 ° with respect to the horizontal plane.
[Selection] Figure 2

Description

  The present invention relates to a film forming apparatus, and more particularly to a technique of an adhesion preventing plate that prevents film formation on a chamber inner wall.

  Sputtering apparatuses are actively used in various fields of industry as film forming apparatuses for forming a thin film on the surface of an object. In particular, in the manufacture of various electronic devices such as LSIs, a sputtering apparatus is frequently used to create various conductive films and insulating films (see, for example, Patent Document 1).

An example of such a conventional sputtering apparatus is shown in FIG.
The sputtering apparatus 50 includes a chamber 51, and a target 52 is disposed at an upper position in the internal space of the chamber 51. A stage 53 is attached to the lower space (insulated from the wall surface of the chamber 51) in the internal space of the chamber 51, and a substrate (film formation target) 58 is placed on the stage 53. Is done.

  A sputtering power supply 61 is connected to the target 52, and the chamber 51 is connected to the ground potential. Then, by applying a negative voltage from the sputtering power supply 61 to the target 52, the material constituting the target 52 jumps out as sputtering particles from the surface of the target 52.

  During such film formation by sputtering, sputtering particles emitted from the target 52 are deposited not only on the surface of the substrate (film formation target) 58 but also on the exposed surface in the chamber 51. In order to prevent the sputtered particles from being deposited on the inner wall of the chamber 51, an adhesion preventing plate is disposed.

  The adhesion preventing plate is made of, for example, an aluminum alloy surface anodized, and the like. The substantially cylindrical upper adhesion preventing plate 57 that surrounds the inner wall of the chamber 51 along the vertical direction of the chamber 51, and the periphery of the stage 53. A ring-shaped lower adhesion-preventing plate 56 and the like formed so as to surround is disposed. The upper surface 56 a of the lower deposition preventing plate 56 has an obtuse step corresponding to the shape in the chamber 51.

JP 2002-129320 A

  In a sputtering apparatus (film forming apparatus), the temperature difference between a high temperature environment (for example, 300 ° C. to 400 ° C.) at the time of film formation and a room temperature environment after film formation is large. Repeats expansion and contraction each time. Therefore, the thin film formed on the deposition preventive plate is easy to peel off, and when it is a hard thin film (hard film), the thin film is cracked.

  In particular, in the past, an angled step was formed on the upper surface of the lower deposition plate facing the target, so stress during expansion and contraction tends to concentrate on the stepped portion, and the deposited thin film peels off and particles There was a problem that a large amount of was likely to occur.

  The present invention has been made to solve the above-mentioned problems, and deposits deposited on an adhesion-preventing plate by sputtering make it difficult to peel off even when stress during expansion and contraction is applied, so that particles in the chamber can be separated. A film forming apparatus capable of suppressing diffusion is provided.

In order to solve the above problems, the present invention provides the following film forming apparatus.
That is, the film forming apparatus of the present invention includes a chamber for storing a target, a stage on which a film to be deposited is placed on one surface of the target with a predetermined interval, the stage, and the stage. A cylindrical upper protection plate that extends in a substantially vertical direction along the inner peripheral surface of the chamber between the target and a ring that surrounds the periphery of the stage and extends from the stage toward the inner peripheral surface of the chamber A lower deposition plate, and a lift for moving the lower deposition plate up and down along the vertical direction,
The lower deposition-preventing plate is configured as a flat surface from an upper surface side facing the target to a position overlapping at least a lower end of the upper deposition-preventing plate, and a lower surface opposite to the upper surface side On the side, a protrusion protruding in a direction away from the upper surface side is formed,
A groove portion that engages with the ridge is formed, and a bottom deposition plate abutting against the lower surface side of the lower deposition plate is provided.

    What is necessary is just to provide the some guide member which contact | abuts to the outer peripheral surface of the said lower adhesion prevention board, and urges | biases the said lower adhesion prevention board in a horizontal direction. Moreover, the flat surface of the said lower adhesion prevention board should just incline in the range of 5 degrees-20 degrees with respect to a horizontal surface.

The lower protection plate may be entirely formed by cutting a metal, and the surface may be blasted and covered with a sprayed film.
The inner diameter of the lower deposition preventing plate may be set in the range of −5 mm to +20 mm with respect to the diameter of the film to be deposited placed on the stage.

    The lift may be moved up and down in the range of 20 mm to 40 mm along the vertical direction of the lower adhesion-preventing plate.

  According to the film forming apparatus of the present invention, the upper surface side of the lower deposition plate on which a large amount of sputtering material is deposited is formed as a flat surface. The stress does not concentrate on a specific portion on the upper surface side of the deposition preventing plate. Therefore, it is difficult for the deposit deposited on the flat surface to peel off, and it is possible to reliably prevent the substrate from being contaminated by the deposit.

It is sectional drawing which shows the film-forming apparatus of one Embodiment of this invention. It is sectional drawing which shows the vicinity vicinity of a lower adhesion prevention board. It is sectional drawing which shows an example of the conventional film-forming apparatus.

    Hereinafter, a film forming apparatus according to the present invention will be described with reference to the drawings. Note that this embodiment is described by way of example in order to better understand the gist of the invention, and does not limit the present invention unless otherwise specified. In addition, in the drawings used in the following description, in order to make the features of the present invention easier to understand, there is a case where a main part is shown in an enlarged manner for the sake of convenience. Not necessarily.

FIG. 1 is a plan view showing a configuration example of a sputtering apparatus which is an example of a film forming apparatus of the present invention.
The sputtering apparatus (film forming apparatus) 10 includes a chamber (vacuum tank) 11. In the internal space of the chamber 11, a target 12 is disposed above the vertical direction. In addition, a stage 13 is formed in the inner space of the chamber 11 and in a state of being insulated from the chamber 11, for example.

  Such a stage 13 supports an object to be film-formed, for example, a substrate (film-formed object) 18 such as a silicon wafer. For example, an electrode having an adsorption function is disposed inside the stage 13. When the inside of the chamber 11 is evacuated, the substrate 18 is placed on the chamber 13, and a voltage is applied to the adsorption electrode, the substrate 18. May be electrostatically attracted to the surface of the stage 13.

    A sputter power source 21 is connected to the target 12. A rotating disk is installed on the atmosphere side of the target, and a permanent magnet is fixed to the rotating disk to give a magnetic field to the vacuum side of the target. The chamber 11 is connected to the ground potential (GND). After evacuating the chamber 11 and electrostatically adsorbing the substrate 18 on the stage 13, a sputtering gas (for example, mixed gas (argon gas + nitrogen gas)) is introduced into the chamber 11, and the sputtering power source 21 is activated. By applying a negative voltage to the target 12, plasma is generated near the surface of the target 12. When ionized ions generated in the plasma are incident on the target 12, the substance constituting the target 12 jumps out of the surface of the target 12 into the chamber 11 as sputtered particles S.

    In the sputtering apparatus 10, an earth shield 15 is installed so as to surround the target 12, and an upper deposition plate (upper shield) 16, and a space located between the target 12 and the stage 13, and Lower protection plates (lower shields) 17 are arranged respectively. The earth shield 15, the upper deposition plate 16, and the lower deposition plate 17 constitute an anode, and all are placed at a ground potential (GND) that is the same potential as the chamber 11. As a result, a thin film made of the material constituting the target 12 and the sputtering gas material is formed on the substrate and the deposition preventing plate.

    On the other hand, high frequency power is applied to the stage 13 by a bias power source 22, and the substrate 18 is placed at a negative potential by self-bias. Accordingly, electrons in the plasma are attracted to the anode, and sputtered particles having positive charges that have jumped out of the target 12 and ionized Ar cations are attracted to the substrate 18. For this reason, sputtered particles having positive charges and ionized Ar cations collide with the surface of the substrate 18 to generate an effect of etching the material deposited on the substrate.

    In such a sputtering apparatus 10, the sputtering particles emitted from the target 12 diffuse into the chamber 11 during film formation. In order to prevent such sputtered particles from adhering to and depositing on the inner wall of the chamber 11, an upper protective plate 16 and a lower protective plate 17 are provided.

    Among these, the upper adhesion prevention board 16 is formed in the cylinder shape extended in the substantially perpendicular direction along the internal peripheral surface (side wall) 11a of the chamber 11 between the stage 13 and the target 12, for example. That is, it is only necessary that the upper deposition preventing plate 16 extends in the vertical direction along the inner peripheral surface of the chamber 11 and the lower end region is bent.

On the other hand, the lower protection plate 17 is formed in a ring shape that surrounds the peripheral region (edge portion) of the stage 13 and extends from the stage 13 toward the inner peripheral surface (side wall) 11 a of the chamber 11.
In addition, a bottom deposition plate 19 that fits with the bottom surface of the lower deposition plate 17 is formed at the bottom of the lower deposition plate 17. The structure of the lower protective plate 17 and its periphery will be described in detail later.

FIG. 2 is an enlarged cross-sectional view of the vicinity of the lower deposition preventing plate in the sputtering apparatus (film forming apparatus). In FIG. 2, the lower deposition preventing plate is shown as a cross section perpendicular to the ring-shaped circumferential direction.
The lower protection plate 17 has a flat surface 31 from the inner peripheral edge 17c where the upper surface side 17a facing the target 12 (see FIG. 1) is close to the stage 13 to a position at least overlapping the lower end 16E of the upper protection plate 16 It consists of Such a flat surface 31 may be, for example, an inclined surface that spreads from the inner peripheral edge 17 c toward the inner peripheral surface (side wall) 11 a of the chamber 11 within an angle θ of 5 ° to 20 ° with respect to the horizontal plane.
In addition, the flat surface here is a surface which does not have protrusions or steps having irregularities or angles in the surface and spreads uniformly.

    The outer peripheral side of the flat surface 31 of the lower protection plate 17 rises upward and is inclined so that the upper end region overlaps the outside of the upper protection plate 16. The outer periphery of the portion where the lower deposition preventing plate 17 rises upward is an outer peripheral surface 17d.

    On the other hand, a ridge 32 protruding in a direction away from the upper surface side 17a is formed on the lower surface side 17b opposite to the upper surface side 17a. Further, a notch 33 is formed in the outer peripheral region of the lower surface 17b of the lower deposition preventing plate 17 toward the upper surface 17a.

    The bottom adhesion preventing plate 19 is in contact with the lower surface side 17b of the lower adhesion preventing plate 17 on the upper surface side 19a. A groove portion 36 that engages with the protrusion 32 of the lower protection plate 17 is formed in the bottom protection plate 19. With such a configuration, the lower deposition preventing plate 17 and the bottom deposition preventing plate 19 are engaged with each other by a bent labyrinth structure, and the sputtering particles diffuse below the bottom deposition preventing plate 19 (for example, the bottom of the chamber 11). Suppress.

    A support member 37 that supports the lower protection plate 17 from the lower surface side 17b contacts the notch 33 formed in the outer peripheral region of the lower protection plate 17. A lift 25 is formed at one end of the support member 37. The lift 25 moves the support member 37 up and down along the vertical direction. Thereby, the lower deposition preventing plate 17 is supported by the support member 37 and can be moved up and down within a predetermined height range with respect to the stage 13.

    Thereby, for example, the lower adhesion plate 17 is lowered by the lift 25, that is, the inner peripheral edge 17c of the lower adhesion plate 17 is set to a position substantially the same as the height position of the substrate 18 placed on the stage 13, A film forming process of the substrate 18 is performed. Also, the lower adhesion plate 17 is moved to the raised position by the lift 25, that is, the inner peripheral edge 17 c is higher than the substrate 18, and the substrate 18 is attached to and detached from the stage 13.

  The support member 37 is formed with a plurality of guide members 38 that abut against the outer peripheral surface 17d of the lower deposition preventing plate 17 and urge the lower deposition preventing plate 17 in the horizontal direction Q. The guide member 38 is composed of, for example, an elastic member such as a spring, a roller, and the like, and urges the lower protection plate 17 from a plurality of locations on the outer peripheral surface 17d toward the center, thereby The center is held so as to coincide with the center of the stage 13. In addition, the guide member 38 supports the lower protection plate 17 in contact with a roller or the like, so that the lower protection plate 17 can be easily detached from the support member 37 and the maintainability can be improved.

  Even when the temperature of the lower deposition preventive plate 17 becomes high due to the plasma, sputtered particles, and Joule heat due to the current during sputtering, and the thermal expansion of the lower deposition preventive plate 17 occurs, the elasticity of the guide member 38 causes the lower protection. The thermal expansion of the landing plate 17 is absorbed. As a result, the center position of the lower deposition preventive plate 17 is maintained, and the screw breakage that occurs when the guide and the lower deposition preventive plate 17 are fixed with screws or the fixed portion between the deposition preventive plate and the guide is rubbed. Can be prevented from occurring.

The lower deposition-preventing plate 17 is formed by cutting a metal such as stainless steel. The surface of the lower deposition preventing plate 17 may be blasted and the entire surface may be covered with a sprayed film.
The material of the lower deposition preventing plate 17 may be other than stainless steel, for example, an alumite-processed surface of an aluminum alloy.

  The difference between the inner diameter of the lower deposition preventing plate 17 and the diameter of the substrate (film formation object) 18 placed on the stage 13 is set to, for example, a range of −5 mm to +20 mm when the substrate is 300 mm. (It is shown as t which is 1/2 of this difference in FIG. 3).

In addition, an example of the size range of each part of the lower adhesion prevention board 17 shown in FIG. 2 is shown. Note that these do not limit the size of the lower deposition preventing plate 17.
Thickness h1: 20-60 mm in the vicinity of the inner peripheral edge 17c
Height h2 of the ridge 32: 40 to 60 mm
The horizontal length w1: 100-140 mm of the notch 33
Horizontal length w2 of the protrusion 32 with the notch 33: 300 to 500 mm
The thickness h3 of the lower deposition preventing plate 17 at the notch 33: 110 to 150 mm
Height h4 in the vertical direction of the notch 33: 40 to 80 mm

    According to the sputtering apparatus (film formation apparatus) 10 configured as described above, the upper surface side 17a facing the target 12 in the lower deposition preventing plate 17 is flattened to at least a position overlapping the lower end 16E of the upper deposition preventing plate 16. Since the surface 31 is used, stress does not concentrate on a specific region.

  That is, in the sputtering apparatus 10, the inside of the chamber 11, particularly the substrate 18 and its surroundings, becomes a high temperature environment during film formation. Further, since the upper surface side 17a of the lower deposition preventing plate 17 faces the target 12, the deposition of the sputtering material increases. For example, if there are protrusions or steps having irregularities or angles on the upper surface side 17a of the lower protective plate 17, stress concentrates on these portions due to expansion and contraction due to repeated high temperature environment and room temperature environment. Then, in the conventional lower deposition-preventing plate having a step or the like, the deposit deposited on the upper surface side is peeled off, and the substrate which is the film formation object is easily contaminated.

  However, like the lower deposition plate constituting the sputtering apparatus 10 of the present invention, the lower deposition plate due to a large temperature difference is obtained by making the upper surface side 17a of the lower deposition plate 17 with much deposition of the sputtering material a flat surface 31. Even if the expansion and contraction of the plate 17 are repeated, the stress does not concentrate on a specific portion on the upper surface side 17 a of the lower deposition preventing plate 17. Therefore, the deposit deposited on the flat surface 31 becomes difficult to peel off, and it is possible to reliably prevent the substrate 18 from being contaminated by the deposit.

DESCRIPTION OF SYMBOLS 10 Sputtering apparatus (film-forming apparatus), 11 Chamber, 12 Target, 13 Stage, 16 Upper deposition plate, 17 Lower deposition plate, 25 Lift, 31 Flat surface, 32 Projection

Claims (6)

A chamber for storing a target; a stage on which a film-deposited object is placed; and a inner surface of the chamber between the stage and the target. A cylindrical upper protective plate extending in a substantially vertical direction along the surface; a ring-shaped lower protective plate surrounding the periphery of the stage and extending from the stage toward the inner peripheral surface of the chamber; and the lower protective plate A lift that moves the deposition plate up and down along the vertical direction;
The lower deposition-preventing plate is configured as a flat surface from an upper surface side facing the target to a position overlapping at least a lower end of the upper deposition-preventing plate, and a lower surface opposite to the upper surface side On the side, a protrusion protruding in a direction away from the upper surface side is formed,
A film forming apparatus, comprising: a bottom deposition preventing plate that is formed with a groove portion that engages with the protrusion, and that contacts a lower surface side of the lower deposition preventing plate.   2. The film forming apparatus according to claim 1, further comprising a plurality of guide members that abut against the outer peripheral surface of the lower deposition preventing plate and urge the lower deposition preventing plate in a horizontal direction.   3. The film forming apparatus according to claim 1, wherein a flat surface of the lower deposition preventing plate is inclined within a range of 5 ° to 20 ° with respect to a horizontal plane.   4. The lower protection plate is formed by cutting a metal as a whole, the surface is subjected to blasting, and is covered with a sprayed film. Deposition device.   5. The inner diameter of the lower deposition preventing plate is set in a range of −5 mm to +20 mm with respect to the diameter of the film to be deposited placed on the stage. The film-forming apparatus of description. The film forming apparatus according to claim 1, wherein the lift moves the lower deposition preventing plate up and down within a range of 20 mm to 40 mm along a vertical direction.

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