JP4223614B2 - Sputtering method and apparatus, and electronic component manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a film thickness distribution, a composition ratio distribution, an impurity attached to a substrate by a target having a diameter equal to or less than the diameter of the substrate in sputtering for semiconductors and various electronic components that require a thin film formation process in vacuum. The present invention relates to a sputtering method and apparatus for the purpose of uniforming the distribution over a wide range and an electronic component manufacturing method .
[0002]
[Prior art]
In the conventional sputtering apparatus, the substrate surface and the target surface are arranged in parallel. In such a conventional sputtering apparatus, a target having a diameter larger than that of the substrate is used in order to make the film thickness distribution, composition ratio distribution, impurity distribution, etc. of the film attached to the substrate uniform over a wide range.
[0003]
In addition, in the multi-source sputtering apparatus in which a plurality of cathodes are inclined with the central axis directed toward the center of the substrate for the purpose of forming an alloy film or a multilayer film, the film thickness distribution, composition ratio distribution, and impurity distribution are poor. It could only be used with a substrate diameter smaller than the target diameter and was used exclusively for research purposes and was not industrial.
[0004]
[Problems to be solved by the invention]
However, since the above-mentioned conventional apparatus had to increase the diameter of the target further as the substrate diameter increased, it is possible to produce the target with the material when the target diameter increases. Some were difficult. For example, Mn and Mn-rich alloys are brittle and easily broken, making it difficult to produce a large target.
[0005]
In addition, if the substrate diameter becomes too large, the influence of the non-erosion region of the target on the film thickness distribution becomes large, etc., so that the film thickness distribution, composition ratio distribution, There is also a problem that the impurity distribution cannot be made uniform.
[0006]
[Means for Solving the Problems]
The present invention comprises a substrate set rotatably and a target,
The diameter of the substrate is d, the diameter of the target is D, the angle formed by the central axis of the target with respect to the normal of the substrate is θ, and the intersection of the central axis of the target and a plane including the surface of the substrate is P, When the distance between the intersection P and the rotation axis of the substrate is F, and the distance between the intersection P and the center of the target is L, the target satisfies the following condition, and the intersection P is outside the substrate. A sputtering apparatus characterized in that one or a plurality are provided at a position to solve the above-mentioned conventional problems, and a uniform film thickness and film quality can be generated even if the target diameter is equal to or less than that of the substrate. It is a thing.
d ≧ D
15 ° ≦ θ ≦ 45 °
50mm ≦ F ≦ 400mm
50mm ≦ L ≦ 800mm
The sputtering apparatus of the present invention includes a plurality of the targets, and the plurality of targets are provided in a rotationally symmetrical manner with respect to the rotation axis of the substrate.
Moreover, this invention provides the sputtering method characterized by performing the film-forming by sputtering on the said board | substrate, rotating the said board | substrate using the sputtering apparatus of the said invention.
Furthermore, the present invention provides a method for manufacturing an electronic component, comprising the step of forming a film by sputtering on the substrate while rotating the substrate using the sputtering apparatus of the present invention.
[0009]
In the present invention, and the normal to the substrate, also the angle θ between the center axis of the target be less than 15 degrees, even if it exceeds 45 degrees, none of the set composition ratio distribution and impurity distribution unevenly It has been found that the film quality is deteriorated.
[0010]
In addition, a decrease in the thin film distribution was observed regardless of whether the distance between the substrate and the target was less than 50 mm or more than 800 mm. Furthermore, the uniformity of the film thickness distribution is poor both when the distance between the intersection axis P of the center axis of the sputtering cathode, the plane including the substrate, and the rotation axis of the substrate is less than 50 mm or more than 400 mm, and the film quality is deteriorated. Admitted. Further, the rotation speed of the substrate varies depending on the sputtering position (distance from the center), but usually exceeds 4 rpm and is preferably less than 60 rpm.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention includes a target having a diameter D and a center axis A of an angle θ with respect to a normal H of a substrate having a diameter d rotating at an appropriate speed V, and includes the normal H, the center axis A, and the substrate. A method and apparatus for sputtering by appropriately determining an offset distance F of an intersection P with a surface and appropriately setting a distance L between a target and a substrate, the ratio of the substrate diameter d to the target diameter D The numerical values of the angle θ, the distances F, and L are as follows.
[0012]
Rotation speed 4rpm ≦ V ≦ 60rpm
Angle θ 15 ° ≦ θ ≦ 45 °
Diameter d and D d ≧ D
Distance F 50mm ≦ F ≦ 400mm
Distance L 50mm ≦ L ≦ 800mm
[0013]
【Example】
An embodiment of the present invention will be described with reference to FIGS. The substrate 2 is set on the disk 5 of the rotating shaft 4, and the sputtering cathode 1 is disposed obliquely above the substrate 2, and the central axis A thereof is θ = 30 ° with respect to the normal H of the substrate 2. It is constructed like this.
[0014]
In this case, the diameter of the substrate 2 is 4 inches, the diameter of the target 3 is 2 inches, the distance F between the rotation axis B and the normal H of the substrate 2 is 60 mm, and the distance L between the target 3 and the substrate 2 is 300 mm. there were.
[0015]
When sputtering was performed under the above conditions, the film thickness distribution with respect to a distance of -40 to 40 mm from the center of the substrate 2 was ± 2.0% or less (FIG. 5).
[0016]
Next, another embodiment in which the arrangement of the targets 3 is different will be described. This is an embodiment in which two cathodes 1a and 1b are arranged symmetrically with respect to the rotation axis B with respect to the substrate 2 (FIG. 2). Further, in this embodiment, two cathodes 1a and 1b are arranged symmetrically with respect to a vertical plane with respect to the substrate 2 (FIG. 3). Furthermore, in this embodiment, six cathodes 1a, 1b, 1c, 1d, 1e, and 1f are arranged symmetrically with respect to the substrate 2 (FIG. 4).
[0017]
FIG. 7 shows a case where a thin film is formed by sputtering on a substrate having a diameter of 350 mm using a target 3 having a diameter of 8.5 inches on a 9.3 inch diameter RMC (FIG. 6). It is a sex simulation result. Here, as shown in FIG. 6, a vertical distance between the center of the target 3 and the substrate 2 is newly defined (referred to as a T / S vertical distance). The T / S vertical distance is determined by L and θ (L cos θ). Thereby, the vertical distance between T / S and the distance F which can ensure within +/- 1.0% can be calculated | required. Since the T / S vertical distance is actually used as a device parameter, it is newly defined in the embodiment.
[0018]
Moreover, the film thickness shape simulation result in the T / S vertical distance and distance F calculated | required in FIG. 7 is shown. In this simulation, a film thickness distribution of ± 0.58% was obtained in a 350 mm diameter plane using a 9.3 inch diameter RMC (FIG. 8). In this case, when the actually measured values were plotted, the film thickness distribution of ± 0.60% was obtained almost in agreement with the simulation.
[0019]
Next, in FIG. 9, when the film thickness distribution dependency by the film forming pressure at the T / S vertical distance of 380 mm was tested, it was found that the film thickness distribution deteriorated as the film forming pressure increased. This is presumably because the sputtered particles are affected by the scattering of the sputtering gas.
[0020]
Therefore, in order to suppress the influence of scattering in a region where the film forming pressure is high, an experiment was conducted with the T / S vertical distance being close. FIG. 10 shows the T / S vertical distance dependence of the film thickness distribution within a 350 mm diameter plane. As a result of being closer to 60 mm than the T / S vertical distance calculated from the simulation, it was possible to satisfy ± 1.0% or less in a plane with a diameter of 350 mm in the film thickness distribution.
[0021]
Therefore, it was found that the film thickness distribution can be secured by adjusting the T / S vertical distance.
[0022]
This invention was compared with the prior art. That is, a simulation for obtaining a film thickness uniformity of ± 1.0% or less within a plane of 350 mm in diameter when using the stationary facing film formation method was performed, and the result of FIG. 11 was obtained. According to FIG. 11, in order to reduce the film thickness distribution to ± 1.0% or less in the stationary facing film formation method, the target size is set to 40 inches or more in diameter, or the vertical distance between the target 3 and the substrate 2 is 1800 mm. It is necessary to do more. On the other hand, if the oblique incidence rotation method is employed, sputtering with a film thickness distribution of ± 1.0% or less can be performed at a vertical distance of 380 mm between the target 3 and the substrate 2 even if the target 3 has a diameter of 8.5 inches.
[0023]
【The invention's effect】
According to the sputtering method and apparatus of the present invention, the film thickness distribution to produce a substrate using a smaller target diameter than the substrate diameter, composition ratio distribution is effective that can be extensively homogenize the impurity distribution.
[0024]
As described above, even if the substrate has a large diameter, the target can be formed with a relatively small diameter with sufficiently high accuracy, and the vertical distance between T / S can be shortened, so that the apparatus can be downsized. is there.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of an embodiment of an apparatus of the present invention.
FIG. 2 is a conceptual diagram of another embodiment.
FIG. 3 is a conceptual diagram of an embodiment in which two cathodes are similarly arranged symmetrically on a vertical plane.
FIG. 4 is a conceptual diagram of an embodiment in which several cathodes are similarly arranged.
FIG. 5 is also a graph of film thickness—distance from the substrate center.
FIG. 6 is a conceptual diagram showing the mutual relationship between the substrate and the target.
FIG. 7 is a graph of the same offset distance-T / S vertical distance.
FIG. 8 is also a normalized film thickness-distance graph from the substrate center.
FIG. 9 is a graph of film thickness distribution-deposition pressure dependency.
FIG. 10 is also a graph of film thickness distribution-T / S vertical distance.
FIG. 11 is also a graph of film thickness distribution-T / S vertical distance.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cathode 2 Substrate 3 Target A Center axis B Rotation axis H Normal D Target diameter d Substrate diameter F B-H distance P A-H intersection 0 Substrate center V Rotational speed

Claims (4)

A substrate set in a rotatable manner and a target,
The diameter of the substrate is d, the diameter of the target is D, the angle formed by the central axis of the target with respect to the normal of the substrate is θ, and the intersection of the central axis of the target and the plane including the surface of the substrate is P, When the distance between the intersection P and the rotation axis of the substrate is F, and the distance between the intersection P and the center of the target is L, the target satisfies the following condition, and the intersection P is outside the substrate. One or a plurality of sputtering apparatuses are provided at positions where
d ≧ D
15 ° ≦ θ ≦ 45 °
50mm ≦ F ≦ 400mm
50mm ≦ L ≦ 800mm 2. The sputtering apparatus according to claim 1, wherein a plurality of the targets are provided, and the plurality of targets are provided rotationally symmetrically with respect to a rotation axis of the substrate. A sputtering method using the sputtering apparatus according to claim 1 or 2, wherein a film is formed by sputtering on the substrate while rotating the substrate. 3. A method of manufacturing an electronic component, comprising: using the sputtering apparatus according to claim 1 or 2 and performing a film formation by sputtering on the substrate while rotating the substrate.

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