JP2012077360A - Cathode unit and film deposition system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode unit capable of equalizing a film thickness at high accuracy, and to provide a film deposition system.SOLUTION: The cathode unit 15 includes: a target material 17 arranged in a sputtering chamber 13; a backing plate 19 to which the target material is attached; and a magnet 29 arranged on the back side of the backing plate at predetermined intervals, wherein the cathode unit has a magnetic field strength-adjusting mechanism 100.

Description

  The present invention relates to a cathode unit and a film forming apparatus.

  Conventionally, when a thin film is formed on a substrate by sputtering, a film forming apparatus using a magnetron cathode (cathode unit) having a high deposition rate and excellent productivity has been widely used (for example, Patent Documents). 1). In this film forming apparatus, one or more magnetron cathodes are generally arranged in the sputtering chamber along the substrate transport direction. And it is comprised so that a thin film may be formed in a substrate surface by conveying a board | substrate so that the target of a magnetron cathode may be opposed. Note that the substrate is generally deposited while being transported in a standing state so that the deposition surface is parallel to the vertical direction.

  As shown in Patent Document 1, a back plate is provided on the back surface of the target, the target is fixed, and a magnet is arranged at a predetermined distance from the back plate. The magnet is fixed to the yoke, and a rib for supporting the yoke is provided.

JP-A-7-109568

  By the way, with the recent increase in size of the substrate, the magnetron cathode has also increased in size. When the magnetron cathode is increased in size, the back plate to which the target is attached may be warped by its own weight and being pulled by being held in a vacuum state in the sputtering chamber (pressed from the outside atmosphere side). On the other hand, since the magnet is fixed to the yoke and the yoke is further reinforced with ribs, no warping occurs. Therefore, when film formation is performed in this state, the distance between the target and the magnet varies depending on the position in the vertical direction of the film formation surface of the substrate, and the film thickness distribution becomes large. Specifically, since the back plate is warped in a crest so that it becomes a convex top at a substantially intermediate position in the vertical direction, the distance between the target and the magnet is the largest at that position, and the magnetic field is weakened. . As a result, there has been a problem that the film thickness at both ends in the vertical direction of the substrate is increased and the film thickness at the intermediate portion is decreased.

  Therefore, the present invention has been made in view of the above-described circumstances, and provides a cathode unit and a film forming apparatus that can make the film thickness uniform with high accuracy.

  The invention described in claim 1 includes a target material arranged in the sputtering chamber, a back plate to which the target material is attached, and a magnet arranged at a predetermined distance from the back side of the back plate. The cathode unit is characterized by having a magnetic field strength adjusting mechanism.

  According to the first aspect of the present invention, the magnetic field strength adjusting mechanism is adjusted so that the magnitude of the magnetic field applied to the target material becomes substantially uniform, so that the entire surface of the film formation surface of the substrate is substantially uniform. The film can be formed with a film thickness. Therefore, the film thickness can be made uniform with high accuracy.

  The invention described in claim 2 is characterized in that the magnetic field intensity adjusting mechanism is configured such that the magnet is in an in-plane direction parallel to the film formation surface of the substrate and in a direction perpendicular to the traveling direction of the substrate. The center portion is configured to be deformable so as to have a convex shape.

  According to the second aspect of the present invention, the distance between the surface of the magnet and the surface of the target is an in-plane direction parallel to the film formation surface of the substrate and a direction orthogonal to the traveling direction of the substrate. Can be adjusted so as to be equally spaced over the entire length (the total length in the vertical direction). Accordingly, since the magnetic field can be made substantially uniform over the entire length in the vertical direction, the film thickness can be formed substantially uniformly over the entire length in the vertical direction of the substrate.

  The invention described in claim 3 includes a spacer for deforming the magnet by a predetermined amount.

  According to the invention described in claim 3, since the magnet can be deformed using the spacer, the deformation amount of the magnet can be adjusted with high accuracy.

  The invention described in claim 4 includes a yoke disposed on the back surface side of the magnet and a rib disposed on the back surface side of the yoke, and an adjustment bolt capable of adjusting a gap between the yoke and the rib. And a bundling bolt that binds the yoke and the rib.

  According to the invention described in claim 4, the yoke can be warped using the adjusting bolt and the binding bolt, and the state can be reliably maintained. Therefore, the magnet can be warped by a predetermined amount, and the magnetic field can be made substantially uniform over the entire length of the target vertical direction surface.

  According to a fifth aspect of the present invention, in the film forming apparatus, the cathode unit according to any one of the first to fourth aspects is provided.

  According to the invention described in claim 5, by adjusting the magnetic field intensity applied to the target material by the magnetic field intensity adjusting mechanism so as to be substantially uniform, it is substantially uniform over the entire film formation surface of the substrate. The film can be formed with a film thickness. Therefore, it is possible to provide a base having a uniform film thickness with high accuracy.

  According to the present invention, the magnetic field strength adjusting mechanism is adjusted so that the magnitude of the magnetic field applied to the target material becomes substantially uniform, thereby forming a film with a substantially uniform film thickness over the entire film formation surface of the substrate. can do. Therefore, the film thickness can be made uniform with high accuracy.

It is a schematic block diagram of the sputter film deposition apparatus in embodiment of this invention. It is the A section enlarged view of FIG. It is a perspective view of the magnetic circuit (consisting of a permanent magnet, a yoke and a rib) in an embodiment of the present invention. It is a fragmentary sectional view which shows the fixing direction of the yoke and rib in embodiment of this invention. It is a perspective view of the spacer in the embodiment of the present invention. It is a side view explaining the state of the magnetron cathode at the time of film-forming a board | substrate with the sputter film deposition apparatus in embodiment of this invention. It is a figure which shows the film thickness distribution in the perpendicular | vertical direction of a board | substrate at the time of forming into a film with the sputtering film-forming apparatus in embodiment of this invention. It is a figure which shows the film thickness distribution in the perpendicular direction of a board | substrate at the time of film-forming a board | substrate with the conventional sputter film-forming apparatus. It is a graph which shows the relationship between the dispersion | variation ((DELTA) T / M) of the distance of the target and permanent magnet in a perpendicular direction, and the dispersion | variation in the surface magnetic field intensity at that time.

A sputter deposition apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic configuration diagram (plan view) of a main part of a sputter deposition apparatus. As shown in FIG. 1, the sputter deposition apparatus 10 is a mass production type in-line sputtering apparatus. A substrate 21 is placed on a carrier 11 driven at a constant speed, and the inside of the sputtering chamber 13 continues in the direction of arrow X. Are sequentially conveyed. The substrate 21 is transported in the horizontal direction in a state where the deposition surface 21a is placed so as to be parallel to the vertical direction. Further, as the transport means for the carrier 11 (substrate 21), a transport means such as a transport roller connected to a motor or a rack and pinion mechanism can be used. Alternatively, the substrate 21 may be transported by holding the upper edge and the lower edge of the substrate 21 with a grooved rotor and rotating the grooved roller with a motor or the like. Further, the inside of the sputtering chamber 13 is configured to be maintained in a vacuum atmosphere.

  A magnetron cathode (cathode unit) 15 is disposed at a position facing the film formation surface 21 a of the substrate 21. A target 17 is disposed on the surface of the magnetron cathode 15 facing the substrate 21. The target 17 is metal-bonded to a backing plate (back plate) 19 and attached to the wall surface 25 of the sputtering chamber 13 via an insulating plate 23.

  A yoke 27 is disposed on the back side (atmosphere side) of the backing plate 19, and a permanent magnet 29 is provided on the surface 27 a of the yoke 27. The yoke 27 is supported by columnar ribs 28 provided on the back surface 27 b of the yoke 27. This rib 28 is a strong thing manufactured, for example with steel.

  Further, as shown in FIGS. 2 and 3, on the surface 27a of the yoke 27, there are a bar-shaped central magnet 29a arranged so as to be parallel to the vertical direction when viewed from the backing plate 19, and the periphery of the central magnet 29a. Two sets of magnet groups 29c each including an outer peripheral magnet 29b arranged in a rectangular shape so as to surround the magnet are arranged.

  The central magnet 29a and the outer peripheral magnet 29b are both magnetized in the direction perpendicular to the film-forming surface 21a of the substrate 21, and the central magnet 29a and the outer peripheral magnet 29b are magnetized in opposite directions. For example, the surface of the central magnet 29a is magnetized to the S pole, and the surface of the outer peripheral magnet 29b is magnetized to the N pole. By arranging the permanent magnet 29 in this way, a magnetic field is formed between the central magnet 29a and the outer peripheral magnet 29b. The permanent magnet 29 may be configured to reciprocate along the transport direction of the substrate 21 using a moving device (not shown) made of, for example, a motor.

  Further, the backing plate 19 is provided with a DC power supply device 31 for applying a DC electric field to the target 17. Further, a first gas cylinder 33 in which a sputtering gas supplied into the sputtering chamber 13 is enclosed and a second gas cylinder 35 in which a reactive gas supplied into the sputtering chamber 13 is enclosed are arranged. The first gas cylinder 33 and the second gas cylinder 35 are introduced into the sputter chamber 13 via a pipe 37, and their tips are connected to a gas introduction nozzle 39 so that they can be ejected into the sputter chamber 13.

  Here, as shown in FIG. 4, the yoke 27 and the rib 28 are fastened and fixed by a binding bolt 41. A plurality of bundling bolts 41 can be attached along the axial direction (vertical direction) of the ribs 28. Specifically, a female screw portion 42 is formed in the yoke 27 and a through hole 43 is formed at a position corresponding to the female screw portion 42 in the rib 28. The size of the through hole 43 is larger than the outer shape of the male screw portion 44 of the binding bolt 41 and smaller than the outer shape of the head 45. Therefore, the yoke 27 and the rib 28 can be fastened and fixed by inserting the binding bolt 41 into the through hole 43 of the rib 28 and screwing it with the female screw portion 42 of the yoke 27.

  On the other hand, an adjustment bolt 51 can be attached to the rib 28, and a gap can be formed between the yoke 27 and the rib 28 by the adjustment bolt 51. A plurality of adjustment bolts 51 can be attached along the axial direction (vertical direction) of the ribs 28. Specifically, a female screw portion 52 is formed on the rib 28. The female screw portion 52 is formed so as to penetrate the rib 28. Therefore, by screwing the adjustment bolt 51 into the female screw portion 52 of the rib 28, the tip end portion 53 of the adjustment bolt 51 moves to the yoke 27 side, and the tip end portion 53 comes into contact with the back surface 27 b of the yoke 27. Furthermore, by screwing the adjustment bolt 51, the space between the yoke 27 and the rib 28 can be widened, and a gap can be formed between the yoke 27 and the rib 28.

  That is, the yoke 27 can be bent along the vertical direction by forming a gap between the yoke 27 and the rib 28 by the adjusting bolt 51 while fastening the yoke 27 and the rib 28 with the binding bolt 41. .

  In the present embodiment, the central portion is convex in the in-plane direction parallel to the film formation surface 21 a of the substrate 21 and in the direction (vertical direction) perpendicular to the traveling direction of the substrate 21. It was configured to be bendable. A mechanism for adjusting the magnetic field of the magnetron cathode 15 by curving the yoke 27 and the permanent magnet 29 with respect to the rib 28 in this manner is referred to as a magnetic field strength adjusting mechanism 100. That is, the magnetic field strength adjusting mechanism 100 adjusts the magnetic field strength in the in-plane direction parallel to the film formation surface 21 a of the substrate 21 and in the direction (vertical direction) orthogonal to the traveling direction of the substrate 21. Can do.

  Further, the spacer 61 can be arranged in the gap between the yoke 27 and the rib 28. By arranging the spacer 61 in the gap, the gap can be easily managed. As shown in FIG. 5, the spacer 61 is a plate-like member, and a through hole 62 through which the adjustment bolt 51 can be inserted and a notch 63 for avoiding contact with the binding bolt 41 are formed. A plurality of spacers 61 having different thicknesses may be prepared and used according to the size of the gap, or a plurality of thin spacers 61 may be prepared and the spacers 61 may be stacked according to the size of the gap. And you may make it arrange | position in a clearance gap.

  Next, a method for forming a substrate using the sputter film forming apparatus 10 will be described. Here, a case will be described in which a substrate 21 having a size of (width) 2200 mm × (length) 2500 mm is used to form a film on the film formation surface 21a.

  When the substrate 21 is large as described above, the length of the target 17 serving as the cathode and the backing plate 19 is about 3000 mm. As described above, when the large target 17 and the backing plate 19 are set in the sputter deposition apparatus 10 and the inside of the sputtering chamber 13 is set in a vacuum atmosphere, the target 17 and the backing plate 19 are formed on the substrate 21 as shown in FIG. The central portion is curved so as to have a convex shape in an in-plane direction parallel to the film surface 21a and a direction (vertical direction) orthogonal to the traveling direction of the substrate 21. At this time, the vertical ends of the target 17 and the backing plate 19 and the vertical central portion are bent by about 4 mm.

  Therefore, in the present embodiment, the adjustment bolt 51 is adjusted so that the surface 27a of the yoke 27 is similarly about 4 mm and the central portion in the vertical direction is convex. That is, the target 17 and the permanent magnet 29 are set to be arranged substantially in parallel so that the central portion in the vertical direction of the permanent magnet 29 arranged on the surface 27a of the yoke 27 is convex.

  FIG. 7 shows the result of the film thickness distribution in the vertical direction when the film forming surface 21a of the substrate 21 is formed using the sputter film forming apparatus 10 set as described above. As shown in FIG. 7, the film thickness distribution in the direction along the vertical direction of the substrate 21 was ± 2.2%.

  On the other hand, when the target 17 and the backing plate 19 are bent as in the prior art, the permanent magnet 29 is not bent and is parallel to the vertical direction, and the film formation surface 21a of the substrate 21 is formed in the vertical direction. The result of the film thickness distribution is shown in FIG. As shown in FIG. 8, the film thickness distribution in the direction along the vertical direction of the substrate 21 was ± 3.7%.

  That is, as in the present embodiment, the substrate 21 is formed by bending the permanent magnet 29 according to the bending of the target 17 and arranging the target 17 and the permanent magnet 29 so as to be substantially parallel to each other. The film thickness distribution in the vertical direction can be reduced.

Furthermore, FIG. 9 shows the relationship between the variation in the distance between the target 17 and the permanent magnet 29 in the vertical direction (ΔT / M) and the variation in the surface magnetic field strength at that time. As shown in FIG. 9, if ΔT / M is ± 2 mm or less, the variation in surface magnetic field strength is ± 6% or less. If the variation in surface magnetic field strength is ± 6% or less, the film thickness distribution approaches the film thickness distribution shown in FIG. In the state of FIG. 7, the distance (T / M) between the target 17 and the permanent magnet 29 at both ends in the vertical direction is 34 mm, and T / M does not deviate to the smaller side. That is, the central portion in the vertical direction is deformed into a convex shape, and T / M is always greater than 34 mm. Therefore, if the permanent magnet 29 is curved so that T / M is 34 mm to 36 mm in the central portion in the vertical direction, the variation in the surface magnetic field strength can be reduced and the film thickness distribution can be reduced.
Note that the above-described ΔT / M has a larger allowable value when, for example, T / M is larger (for example, 40 mm).

  According to the present embodiment, the magnetic field strength adjusting mechanism 100 adjusts the magnitude of the magnetic field applied to the target 17 so as to be substantially uniform. A film can be formed with a thickness. Therefore, the film thickness can be made uniform with high accuracy.

  Further, the distance (T / M) between the permanent magnet 29 and the target 17 is an in-plane direction parallel to the film formation surface 21 a of the substrate 21 and orthogonal to the traveling direction of the substrate 21. It was comprised so that it could adjust so that it might become equal intervals over the full length of a direction (full length of a perpendicular direction). Accordingly, since the magnetic field can be made substantially uniform over the entire length in the vertical direction, the film thickness can be formed almost uniformly over the entire length of the substrate 21 in the vertical direction.

  Further, since the permanent magnet 29 can be deformed using the spacer 61, the deformation amount of the permanent magnet 29 can be adjusted with high accuracy.

  Furthermore, the yoke 27 can be warped using the adjusting bolt 51 and the binding bolt 41, and the state can be reliably maintained. Therefore, the permanent magnet 29 can be warped by a predetermined amount, and the magnetic field can be made substantially uniform over the entire length in the vertical direction.

Note that the present invention is not limited to the above-described embodiments, and includes various modifications made to the above-described embodiments without departing from the spirit of the present invention. That is, the specific shapes, configurations, and the like given in the embodiment are merely examples, and can be changed as appropriate.
For example, in the above-described embodiment, the in-line type sputtering film forming apparatus has been described. However, the present invention is not limited to this, and is used for a film forming apparatus having a plurality of chamber chambers that require evacuation, such as a stationary film forming apparatus. can do.

  DESCRIPTION OF SYMBOLS 10 ... Sputter deposition apparatus (deposition apparatus) 13 ... Sputter chamber 15 ... Magnetron cathode (cathode unit) 17 ... Target (target material) 19 ... Backing plate (back plate) 27 ... Yoke 28 ... Rib 29 ... Permanent magnet (magnet) 41 ... Bundling bolt 51 ... Adjustment bolt 61 ... Spacer 100 ... Magnetic field strength adjustment mechanism

Claims (5)

A target material arranged in the sputtering chamber;
A back plate to which the target material is attached;
In a cathode unit provided with a magnet disposed at a predetermined distance apart on the back side of the back plate,
A cathode unit having a magnetic field strength adjustment mechanism.   The magnetic field strength adjusting mechanism is arranged so that the magnet is convex in the in-plane direction parallel to the film formation surface of the substrate and in a direction perpendicular to the traveling direction of the substrate. The cathode unit according to claim 1, wherein the cathode unit is configured to be deformable.   The cathode unit according to claim 1, further comprising a spacer for deforming the magnet by a predetermined amount. A yoke disposed on the back side of the magnet;
A rib disposed on the back side of the yoke,
An adjustment bolt capable of adjusting the gap between the yoke and the rib;
The cathode unit according to any one of claims 1 to 3, wherein a binding bolt for binding the yoke and the rib is attachable.   A film forming apparatus comprising the cathode unit according to claim 1.

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