JP5247405B2 - Vacuum deposition apparatus and member manufacturing method - Google Patents

Description

  The present invention relates to a vacuum deposition apparatus and a film forming method.

  In general, film formation on an optical element such as a lens or a prism is often performed by a vacuum evaporation apparatus. Conventionally, in order to form an optical thin film having a uniform in-plane film thickness distribution on a substrate (for example, a lens) that is an object of film formation, a film is formed while rotating and revolving the substrate. Vapor deposition equipment is used. In addition, a shielding plate that corrects the film thickness is installed between the evaporation source and the substrate of the planetary rotation type evaporation apparatus, and even if the substrate is a flat plate or a curved substrate, the evaporation particles that come from the evaporation source The shape of the shielding plate has been optimized so that the film thickness distribution does not vary due to the relationship between the reach distance and the flying angle. Such a technique is disclosed in Patent Document 1.

  In recent years, lenses used in exposure apparatuses have been increasing in curvature and diameter in order to improve resolution performance. Since the film thickness deposited on the substrate is proportional to the cosine of the angle formed by the normal direction of the substrate surface and the flying direction of the vapor deposition particles, the film thickness tends to be thinner toward the periphery of the lens having a larger curvature and aperture. Therefore, in order to uniformly correct the film thickness for a large curvature, large-diameter lens, the amount of vapor deposition particles shielded by the shielding plate must be increased as the shielding plate is closer to the center of the lens. Therefore, it is necessary to make the shape of the shielding plate steep or to increase the number of shielding plates (increase the area).

  Furthermore, in the exposure apparatus, in order to reduce the unevenness of the transmittance in the pupil plane with a projection optical system from several tens of lenses and mirrors, the film thickness distribution of the antireflection film is controlled in the lens plane and optical characteristics ( A desired transmittance distribution is obtained by changing the incident angle characteristic of the transmittance. Such a technique is started in Patent Document 2.

  And the request | requirement which controls film thickness distribution with still higher precision is increasing. Therefore, it is very important to form an optical thin film having a highly accurate film thickness distribution characteristic within a large area (large diameter) substrate surface.

Positional relationship between vapor deposition particles and lens to be shielded by the installed shielding plate as a cause of the vapor deposition equipment side that causes an error in the film thickness distribution characteristics in the lens plane from the desired value May shift. As a technique for preventing this, Patent Document 3 discloses a vapor deposition apparatus that prevents eccentricity of the rotating shaft of the dome.
Japanese Patent Laid-Open No. 11-106902 JP 2004-271544 A Japanese Patent Laid-Open No. 06-337310

  However, in order to form a lens with a large curvature and a large aperture with high accuracy film thickness distribution characteristics with a conventional shielding plate or vapor deposition apparatus, the shape of the shielding plate is complicated or the number of shielding plates is increased ( It is necessary to increase the area). Therefore, there is a problem that the film thickness distribution in the lens surface is deviated from a desired value due to a slight deviation of the installation position of the shielding plate or a shape error of the shielding plate itself.

  Furthermore, the conventional shielding plate for correcting the film thickness has not been provided with sufficient measures for manufacturing reproducibility and error, while aiming to make the film thickness distribution in the lens surface uniform.

  If the reproducibility of the film thickness distribution in the lens surface is poor, a highly accurate film thickness distribution as used in the optical system of an exposure apparatus is required, and an expensive optical element has a low yield and a low production cost. growing. Therefore, it is a big problem to reduce the manufacturing error of the film thickness distribution in the lens surface.

  An object of the present invention is to provide a vacuum evaporation apparatus capable of forming a film having a uniform film thickness even for a member having a large curvature and a large diameter, for example.

A first aspect of the present invention is a vacuum deposition apparatus, which supports a member, rotates the member around a first axis passing through the center thereof, and has a second axis different from the first axis. A mechanism that revolves around, an evaporation source that is disposed at a distance from the second axis and generates vapor deposition particles for forming a film, and a member that rotates and revolves by the mechanism and the evaporation source And n shielding plates (where n is an integer of 2 or more) that shields deposition particles from adhering to the rotating and revolving members, each of the n shielding plates When the amount that shields the deposition particles from adhering to the rotating and revolving members is Ai (where i = 1 to n), each of the n shielding plates is set so that each of Ai satisfies the following formula. The shape is defined.
(A1 + A2 +... + An) × (1 / n−1 / (5n)) ≦ Ai ≦ (A1 + A2 +... + An) × (1 / n + 1 / (5n))

A second aspect of the present invention is a vacuum deposition apparatus, which supports a member, rotates the member around a first axis passing through the center thereof, and rotates around a second axis different from the first axis. Between the second source and the evaporation source, which is disposed at a distance from the second axis and generates vapor deposition particles for forming a film, and between the member rotated and revolved by the mechanism and the evaporation source And n (where n is an integer of 1 or more) shielding plates that shield the deposition particles from adhering to the rotating and revolving members, each of the n shielding plates The point at which the straight line connecting the intersection of the surface of the member with the vapor deposition particles and the first axis and the evaporation source intersects with the surface of the shielding plate to which the vapor deposition particles adhere moves as the member revolves. Arranged to be divided into two regions by orbital circles, Bi (where i = 1 to 2n) is the amount by which each of 2n areas of the n shielding plates divided by the orbit circles shields the deposition particles from adhering to the rotating and revolving members. At this time, the shape of the n shielding plates is determined so that each of Bi satisfies the following formula.
(B1 + B2 +... + B2n) × (1 / (2n) −1 / (10n)) ≦ Bi ≦ (B1 + B2 +... + B2n) × (1 / (2n) + 1 / (10n))

A third aspect of the present invention is a vacuum deposition apparatus, which supports a member, rotates the member around a first axis passing through the center thereof, and rotates around a second axis different from the first axis. Between the second source and the evaporation source, which is disposed at a distance from the second axis and generates vapor deposition particles for forming a film, and between the member rotated and revolved by the mechanism and the evaporation source And n (where n is an integer of 1 or more) shielding plates that shield the deposition particles from adhering to the rotating and revolving members, each of the n shielding plates The point at which the straight line connecting the intersection of the surface of the member with the vapor deposition particles and the first axis and the evaporation source intersects with the surface of the shielding plate to which the vapor deposition particles adhere moves as the member revolves. A plane including a straight line passing through the center of the orbit circle and parallel to the second axis Therefore, it is divided into two regions, and each of 2n regions generated in the n shielding plates by the division shields the amount of vapor deposition particles from adhering to the rotated and revolved member Ci (where i = 1 to 2n), the shapes of the n shielding plates are determined so that there are the planes that satisfy the following formulas for Ci.
(C1 + C2 +... + C2n) × (1 / (2n) −1 / (10n)) ≦ Ci ≦ (C1 + C2 +... + C2n) × (1 / (2n) + 1 / (10n))

  According to the present invention, it is possible to provide a vacuum evaporation apparatus capable of forming a film having a uniform film thickness, for example, on a member having a large curvature and a large diameter.

  Hereinafter, a vacuum deposition apparatus as an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a schematic view showing an example of a vacuum deposition apparatus that can be used in the present invention.

The vacuum vapor deposition apparatus of this embodiment supports a member 10 to be formed during film formation in a vacuum film formation tank 11 sealed so as to be evacuated, and a rotating shaft 14 passing through the center of the member 10. A planetary drive mechanism capable of revolving around the revolution axis 15 while rotating around is provided. The rotation axis 14 constitutes a first axis for rotating the member 10, and the revolution axis 15 constitutes a second axis different from the first axis for revolving the member 10. In FIG. 1A, the rotation shaft 14 and the revolution shaft 15 are provided in parallel. However, as shown in FIG. 1B, a planetary drive mechanism in which the rotation shaft 14 and the revolution shaft 15 are not parallel may be used.
In the vacuum film formation tank 11, an evaporation source 12 that generates vapor deposition particles for forming a film on the member 10 is disposed at a distance from the revolution axis 15.
Further, in the vacuum film formation tank 11, n shielding plates 17 are disposed between the evaporation source 12 and the member 10 to shield the deposition particles from adhering to the member 10 and control the film thickness distribution. Here, n is an integer of 2 or more.

  In this embodiment, the shape of the shielding plate 17 is optimized within the installation plane 16. In the present embodiment, the plane perpendicular to the revolution axis 15 is the installation surface 16 of the shielding plate 17, but all projection images obtained by projecting the shielding plate 17 from the evaporation source 12 between the evaporation source 12 and the member 10 are: The positional relationship is synonymous with the shielding plate 17.

  There is no problem even when a film is formed by a known film forming method, such as an ion-assisted vapor deposition method or an ion plating method.

  Hereinafter, how to determine the specific shape of the shielding plate 17 in the present embodiment will be described.

[Example 1]
Specific numerical values of the vacuum deposition apparatus used in Example 1 are as follows. The height from the floor surface with the evaporation source 12 to the glass substrate 10 as a member to be deposited is 1100 mm, and the height of the installation position of the shielding plate 17 is 980 mm. The length from the revolution shaft 15 to the rotation shaft 14 is 410 mm, and the length from the revolution shaft 15 to the evaporation source 12 is 250 mm. The ratio of rotation and revolution of planetary drive is 2.471 with the rotation direction of rotation and revolution being opposite.

The substrate 10 used in Example 1 is a convex lens having an outer diameter of 300 mm and a curvature radius of 300 mm, and an example in which SiO ₂ is formed with a uniform film thickness distribution on the surface of the substrate 10 on which vapor deposition particles adhere will be described. In this embodiment, the uniform film thickness means that the film thickness distribution in the plane to which the vapor deposition particles adhere is 98% or more. In this embodiment, the desired distribution characteristic is set to a uniform film thickness (film thickness distribution 98%) in the plane, but the film thickness is not limited to a desired value other than 98%. Absent. In addition, the SiO ₂ film formation conditions were ion-assisted deposition using a film formation temperature of 200 ° C. and a film formation pressure of 1 × 10 ⁻³ Pa.

  The final shape and installation position of the shielding plate 17 of Example 1 are as shown in FIG. FIG. 2 is a cross-sectional view when cut in a direction perpendicular to the revolution axis 15 at a height of 980 mm from the evaporation source 12, that is, the shape of the shielding plate 17 on the installation plane 16 of the shielding plate. A total of four shields A, B, C, and D were installed on the straight frames AL, BL, CL, and DL every 90 degrees from directly above the evaporation source 12.

  Next, a method for determining the shape of each shielding plate A to D in the first embodiment will be described.

First, film formation is performed while rotating the convex lens 10 in a planetary state without the shielding plate 17 being installed. In the graph of FIG. 3, MO is the distribution of film thickness at the radial position of the lens normalized by the film thickness at the center of the deposited SiO ₂ lens. At this time, the distribution of the angle at which the evaporation source 12 emits the vapor deposition particles in this vacuum vapor deposition apparatus is obtained simultaneously.

  The film thickness deposited at each position on the surface of the lens 10 is inversely proportional to the square of the distance from the evaporation source 12 to the deposition position, and the amount of vapor deposition particles at the angular position obtained from the distribution of the emission angle α of the evaporation source 12. And the product of the angle formed by the normal direction at each deposition position and the flying direction of the deposited particles. From this relationship, to the shielding plate 17 for depositing an optical thin film having a film thickness distribution characteristic in the same plane, which is the object of the present invention, which is the object of the present invention, at the same time shielding the thicker the deposited position. The shape is deformed to satisfy the following conditions.

  Deciding the shape of the shielding plate 17 means deciding the shielding region of the vapor deposition particles, and at this time, the shielding amount is uniquely determined. On the other hand, even if the amount of shielding for determining the film thickness distribution to be 98% or more is determined, there are an infinite number of combinations of regions to be shielded unless the number and position of the shielding plates 17 are limited.

  In other words, determining the shape of the shielding plate 17 is to find the conditions for forming the film thickness distribution characteristics with good reproducibility from among the numerous combinations of areas to be shielded, and to determine the shape and installation of the shielding plate. It is none other than finding the position efficiently.

In this example, the amount of shielding of the vapor deposition particles by each shielding plate 17 is calculated by a computer so that the total shielding amount is divided by the number of shielding plates 17 (n = 4). It came. That is, when the shielding amount of the vapor deposition particles by each of the n shielding plates 17 is Ai (where i = 1 to n), each of the n shielding plates 17 is such that Ai satisfies the following formula. The shape is defined. In this embodiment, n is 4, but may be an integer of 2 or more.
Ai = (A1 + A2 +... + An) × (1 / n ± 1 / 5n)

  Hereinafter, a method of calculating the shape of the shielding plate that gives the lens (substrate) 10 a uniform film thickness distribution will be described with reference to FIG.

When the lens 10 is divided into n in the radial direction, the film thickness di of the vapor deposition particles adhering to the i-th region when there is no shielding plate is the distribution of the emission angle of the evaporation source 12 f (α), and the vapor deposition particles If the angle of flight of β is β and the distance between the lens and the evaporation source is L, the following is obtained. Note that k is a proportional coefficient.
di = kf (α) cosβ / L ²
(In the example, f (α) = cos ⁿ (α) and n = 1 were set.)
When the shielding plate is not installed, the film thickness Di of the i-th region of the lens attached at the film formation time t is as follows.
Di = ∫ ₀ ^t di dt
Assuming that the film thickness shielded by each of the m shielding plates is M1i, M2i,... Mmi, Mmi is also expressed by the same formula as Di described above.

Then, when m shielding plates are installed, the film thickness Di of the i-th region of the lens attached at the film formation time t is as follows.
Di = ∫ ₀ ^t di dt− (M1i + M2i + ... + Mmi)
In the first embodiment, since M1i = M2i =... = Mmi, Di is as follows.
Di = ∫ ₀ ^t di dt−mM1i
One of the n shielding plates for setting D ₁ = D ₂ =... D _i =... D _n for the film thickness Di in each of the n divided regions of the lens. The shape of the shielding plate A is calculated.

  The calculation flow shown in FIG. 18 will be described. In step S1, the film thickness Di of each area described above is calculated after temporarily setting the shape of the shielding plate A. In step 2, Di is normalized by the maximum value Dmax of Di, and it is determined whether or not all the normalized values Qi (Di / Dmax) are equal to or greater than the target value of 0.98. If it is determined in step S2 that all of Qi are equal to or greater than 0.98, the temporarily set shape is determined and the calculation flow ends.

  If it is determined in step S2 that at least one of Qi is less than 0.98, the calculation flow proceeds to step S3. First, the shielding plate A is slightly deformed. In step S4, the film thickness Di is calculated again based on the shape of the shield plate A that has been slightly deformed.

In step S5, the merit function f _merit = √1 / nΣi _{= 1} ⁿ (1-Q _i ) ² is calculated, and when the merit function f _merit is deteriorated, the direction of minute deformation of the shielding plate A is It is determined that the shielding plate A is slightly deformed in the reverse direction. When the merit function f _merit is improved, it is determined that the shielding plate A is further minutely deformed in the direction of minute deformation of the shielding plate A, and when the merit function f _merit is not changed, the minute deformation of the shielding plate A is determined. Is determined to be canceled. In step S6, the shielding plate A is deformed according to the determination result of step S5. The calculation flow returns to step 1 and the film thickness Di is calculated. And the calculation flow which calculates | requires the shape of the shielding board A is repeated until film thickness distribution becomes 0.98 or more of target value.

  When the shape of the shielding plate A is calculated, the shapes of the other shielding plates B, C,.

Graph B in FIG. 3 shows the distribution of the film thickness with respect to the radial position of the lens normalized by the film thickness at the center of the lens of SiO _{2 formed} without any shield plate when only the shield plate B is installed. It is. Graph B + D is the distribution of film thickness when two shielding plates, shielding plate B and shielding plate D, are installed. Graph A + B + D is the distribution of film thickness when three shielding plates A, B, and D are installed. Graph A + B + C + D is a film thickness distribution when four shielding plates A to D are installed.

  The area surrounded by the graph MO and the graph B corresponds to the shielding thickness shielded by the shielding plate B, and the area surrounded by the graph B and the graph B + D corresponds to the shielding thickness shielded by the shielding plate D. To do. The area surrounded by the graph B + D and the graph A + B + D corresponds to the thickness shielded by the shielding plate A, and the area surrounded by the graph A + B + D and the graph A + B + C + D is shielded by the shielding plate C. It corresponds to.

  The distribution characteristics of the shielding amount along the radial direction of the lens by each of the shielding plates A to D are the same, and the shielding amount by each of the shielding plates A to D is obtained by dividing the total shielding amount into four equal parts (1 / n ± 1 / 5n: n = 4).

At this time, since the film thickness of SiO ₂ is inversely proportional to the square of the distance from the evaporation source 12 to the deposition position, the shielding plate A closest to the evaporation source 12 has the smallest area and the shielding farthest from the evaporation source 12. The plate C has the largest area.

  Next, the film thickness is shielded by the shielding plates B, D, A ′, and C ′ while maintaining the film thickness uniformity by the four shielding plates so that the thickness is 5: 5: 7: 3. The shape of the shielding plates A ′ and C ′ in this case is the shape of the shielding plates A ′ and C ′ in FIG. At this time, the area surrounded by B + D and A ′ + B + D in the graph in FIG. 4 is the film thickness shielded by the shielding plate A ′, and is surrounded by the graph A ′ + B + D and the graph A ′ + B + C ′ + D. The measured area is the film thickness shielded by the shielding plate C ′.

  FIG. 5 is a graph in which the distribution of the film thickness at the radial position of the lens 10 when the four shielding plates A, B, C, and D are installed is normalized by the thickest film thickness. FIG. 6 is a similar graph when four shielding plates A ′, B, C ′, and D are installed. Distribution of film thickness ABCD (FIG. 5) when shielding plates A, B, C, and D are installed without displacement and film thickness when shielding plates A ′, B, C ′, and D are installed without displacement The film thickness distributions A ′, B, C ′, and D are 98% or more and the film thickness distribution is controlled with very high accuracy.

  A +, C +, A ′ + and C ′ + in FIGS. 5 and 6 indicate that the shielding plates A, C, A ′ and C ′ are in the direction of the revolution axis, respectively, A−, C−, A′− and C′−. Is the distribution of film thickness when an installation error of about 10 mm occurs in the opposite direction.

  Shielding plates A, C, B, and D that divide the shielding amount almost evenly give the installation error to shielding plates A and C, but the film thickness distribution worsens by 0.4% at worst, as shown in FIG. However, it can be seen that there is almost no change and the value is over 98%.

  In the shielding plates B, D, A ′, and C ′ having a shielding amount of 5: 5: 7: 3, the shielding amount by the shielding plate A ′ is increased, and the shielding amount by C ′ is decreased. For this reason, when the installation error is given to the shielding plates A ′ and C ′, the influence of the shielding plate A ′ increases and the contribution of the shielding plate C ′ decreases. Referring to FIG. 6, when an installation error is given to the shielding plate A ', the worst value is deteriorated by about 1.5%. The amount of shielding by the shielding plate C ′ is small because the fluctuation value is originally small, but hardly changes.

  Therefore, when an equivalent installation error or shape error is predicted for each shielding plate 17, it is desirable that the amount of shielding by each shielding plate 17 be evenly distributed because the errors are averaged. When the shielding amount by each shielding plate 17 has an error of 20% (1 / n ± 1 / 5n: n = 4) from the uniform distribution value, it is a limit that the desired film thickness distribution is not satisfied. It can be said that the desired film thickness distribution can be controlled within ± 3% within an allowable range within 20% of the uniform distribution value.

  As described above, the shielding plate 17 according to the first embodiment can control the film thickness distribution in the lens surface with high accuracy, and the variation in the film thickness distribution is small with respect to the installation error. Suitable for film formation with good reproducibility of thickness distribution.

[Example 2]
Specific numerical values of the vacuum evaporation apparatus used in Example 2 are as follows. The height from the floor surface where the evaporation source 12 is located to the glass substrate 10 is 1600 mm, and the height of the installation position of the shielding plate is 1490 mm. The length from the revolution shaft 15 to the rotation shaft 14 and the length from the revolution shaft 15 to the evaporation source 12 are 500 mm and 300 mm, respectively. The ratio of rotation and revolution of planetary drive is 2.471 with the rotation direction of rotation and revolution being opposite.

The substrate 10 used in Example 2 is a concave lens having an outer diameter of 316 mm and a curvature radius of 350 mm, and the MgF ₂ is formed so that the center 19 of the lens coincides with the rotation axis 14 and the film thickness distribution in the lens surface is uniform. An example of film formation will be described. Therefore, the uniform film thickness in this embodiment means that the in-plane film thickness distribution is 98% or more. In addition, the MgF2 film formation conditions were a film formation temperature of 250 ° C. and a film formation pressure of 2 × 10 ⁻⁴ Pa.

  The final shape and installation position of the shielding plate 17 of Example 2 are as shown in FIG. FIG. 7 is a cross-sectional view when cut in a direction perpendicular to the revolution axis 15 at a height of 1490 mm from the evaporation source 12, that is, the shape of the shielding plate 17 on the installation plane 16 of the shielding plate. Then, one shielding plate A55 was installed on a straight frame AL arranged just above the evaporation source 12.

O in FIG. 7 is that a straight line connecting the intersection (lens center) 19 of the surface of the lens 10 to which the vapor deposition particles adhere and the evaporation source 12 intersects the surface of the shielding plate 17 to which the vapor deposition particles adhere. It is an orbital circle that moves as the lens 10 revolves. The center of this orbital circle O is O ₀ .

  Next, a method for determining the shape of the shielding plate A in the second embodiment will be described.

  The conditions for forming the optimum shape of the shielding plate A are such that the shielding plate A has an equal amount of shielding the vapor deposition particles in the two regions Ai and Ao divided by the orbital circle O in FIG. It is to provide. In this way, even if an installation error of the shielding plate A occurs in a direction parallel to the straight line AL, the influence on the film thickness distribution is reduced. As a result of calculation by a computer according to this condition, the shape shown in A55 of FIG. 7 was reached.

Further, in FIG. 7, the shape of the shielding plates A64 and A73 in which the shielding amount in each region Ai and Ao is changed from the shielding plate A55 with a uniform shielding amount of 5: 5 to the shielding amount ratio of 4: 6 and 3: 7 is also shown. Show. A graph M0 in FIG. 8 is a graph in which the film thickness distribution of MgF _{2 formed} without the shielding plate 17 is normalized by the film thickness at the center of the lens, and MA indicates the thickness by installing the shielding plate 17. This is a distribution of film thickness when uniform correction is performed. Graphs A55, A64, and A73 divide the area surrounded by graphs M0 and MA, that is, the total film thickness shielded in order to make the film thickness distribution uniform into the shielding amounts by the two regions Ai and Ao, respectively. It is a dividing line. Graph A55 shows that the film thickness is made uniform along the radial position of the lens and the shielding amount is divided into two equal parts (1 / 2n ± 1 / 10n: n = 1). That is, when the shielding amount of the vapor deposition particles by 2n regions in the n shielding plates 17 divided by the orbital circle O is Bi (i = 1 to 2n), each of Bi satisfies the following formula. The shape of the n shielding plates 17 is determined. In this embodiment, n is 1, but it may not be 1 as long as it is an integer of 1 or more.
(B1 + B2 +... + B2n) × (1 / (2n) −1 / (10n)) ≦ Bi ≦ (B1 + B2 +... + B2n) × (1 / (2n) + 1 / (10n))

  9, 10, and 11 show the film thickness distribution when normalized using the thickest film thickness in the lens surface with respect to the lens radial direction position when the film is formed using shielding plates A55, A64, and A73, respectively. It is a graph which shows. The film thickness distribution in the lens surface is 98% or more in all cases, and the film thickness distribution in the surface is controlled with high precision and uniform.

  Further, the graphs A55 +, A64 +, and A73 + in FIGS. 9 to 11 show that the shielding plates A55, A64, and A73 have an installation error of about 10 mm in the direction of the revolving axis, and the A55−, A64−, and A73− have the opposite direction. It is the distribution of the film thickness in the lens surface when it occurs.

  From the shielding plate A55 that divided the shielding amount almost equally in each area Ai, Ao, to A64, A73 that increased the shielding ratio of Ao, even if the installation error given to the shielding plate is the same, in-plane The film thickness distribution is 98.5% at A73, and is more likely to deteriorate.

  Therefore, when the shielding plate 17 is divided by the orbital circle O, it is desirable that the shielding amount is evenly distributed in each region because the fluctuation of the film thickness distribution with respect to the error becomes small. If the shielding amount in each region of the shielding plate deviates from the uniform division, the influence becomes large, but an error of about 20% (1 / 2n ± 1 / 10n: n = 1) is permissible.

  As described above, the shielding plate 17 of Example 2 can control the distribution of the film thickness in the plane with high accuracy, and the fluctuation of the distribution of the film thickness in the plane with respect to the installation error is small. It is suitable for film formation with good reproducibility of film thickness distribution.

[Example 3]
Specific numerical values of the vacuum deposition apparatus used in Example 3 are as follows. The height from the floor surface where the evaporation source 12 is located to the glass substrate 10 is 1000 mm, and the height of the position of the shielding plate 17 is 980 mm. The length from the revolution shaft 15 to the rotation shaft 14 and the length from the revolution shaft 15 to the evaporation source 12 are 500 mm and 250 mm, respectively. The ratio of rotation and revolution of planetary drive is 2.471 with the rotation direction of rotation and revolution being opposite.

The substrate 10 used in Example 3 is a concave lens having an outer diameter of 300 mm and a curvature radius of 250 mm, an example in which MgF ₂ is formed with a uniform film thickness distribution in the plane with the lens center 19 aligned with the rotation axis 14. Is described. Therefore, the uniform film thickness in this embodiment means that the in-plane film thickness distribution is 98% or more. The deposition conditions for MgF ₂ were a deposition temperature of 300 ° C. and a deposition pressure of 4 × 10 ⁻⁵ Pa.

The final shape and installation position of the shielding plate 17 of Example 3 are as shown in FIG. O in FIG. 12 is an orbital circle that moves with the revolution of the lens 10 at the point where the straight line connecting the center 19 of the lens 10 and the evaporation source 12 intersects the surface of the shielding plate 17 to which the vapor deposition particles adhere. Is circular. The shielding plates A to D are each divided into two regions by a plane including a straight line passing through the center O ₀ of the orbital circle O and parallel to the revolution axis 15. The shielding plates A to D are respectively installed on the straight frames AL, BL, CL, DL every 90 degrees from directly above the evaporation source 12. Note that O ₀ does not coincide with the revolution axis 15 because the evaporation source 12 does not exist on the revolution axis 15.

  Since the straight lines AL, BL, CL, and DL correspond to a part of the radius of the orbit circle O, the shielding plates A to D can be installed in a rotationally symmetrical positional relationship.

  Next, a method for determining the shape of each shielding plate A to D in Example 3 will be described.

The condition for forming the shape of each shielding plate A, B, C, D is that when each shielding plate is divided by the frames AL, BL, CL, DL, the vapor deposition particles are divided in each divided region. This is to make the shielding amount Ci equal (1 / (2n) ± 1 / (10n) : n = 4). In this way, even if installation errors of the shielding plates A to D occur in a direction perpendicular to the straight lines AL, BL, CL, and DL, the influence on the film thickness distribution is reduced. As a result of calculation with a computer according to this condition, the shape of FIG. 12 was reached. The shielding amount in a plane including the straight line extending from the center O _{0 of the} orbital circle and the revolution axis 15 or 2n divided by the plane including the straight line and parallel to the revolution axis 15 is Ci (where i = 1 to 2n). At that time, the shapes of the n shielding plates 17 are determined so that each Ci satisfies the following expression. In this embodiment, n is set to 4, but it may not be 4 as long as it is an integer of 1 or more.
(C1 + C2 +... + C2n) × (1 / (2n) −1 / (10n)) ≦ Ci ≦ (C1 + C2 +... + C2n) × (1 / (2n) + 1 / (10n))

  Since the evaporation source 12 and the straight lines AL and CL are on the same plane, the shielding plates A and C are symmetrical with respect to the straight lines AL and CL. The shielding plates B and D have the same shape, and the area of the region closer to the evaporation source 12 than BL and DL is larger on the far side.

  In the third embodiment, in addition to the above conditions, the amount of shielding by one shielding plate, which is a feature of the shielding plate 17 in the first and second embodiments, is substantially equal, and divided by the orbit circle O. We combined the two conditions that the amount of shielding in each area was equal.

  Then, the shielding plates A to D are divided into 16 regions A1 to D4 divided by the straight lines AL, BL, CL, DL and the orbit circle O, respectively. The area between the 16 graphs M0 to D4 in FIG. 13 corresponds to the film thickness shielded by the regions A1 to D4 in FIG. It can be seen that the shielding amount Di (where i = 1 to 4n) is divided into 16 equal parts (1 / 4n ± 1 / 20n: n = 4) in all 4n (16) lens radial direction positions. It is desirable that the amount of shielding in each region be equal, but an error of about 20% is acceptable for the same reason as before.

FIG. 14 is a graph when the film thickness at the lens radial direction is normalized by the film thickness at the center of the lens when MgF ₂ is formed by installing the shielding plates A to D shown in FIG. MM in Fig. 14 is the film thickness distribution in the lens surface when there is no installation error in the shielding plate, which is 98% or more, and the film thickness distribution in the surface is controlled with very high accuracy. Yes.

  In Fig. 14, A +, B +, C + and D + are in-plane when each shielding plate is in the center O0 direction, and A-, B-, C- and D- are in the plane when an installation error of about 10mm occurs in the opposite direction. It is distribution of the film thickness in. Although it worsens 1.2% at the worst value, it can be seen that all maintain the film thickness distribution in the plane of 98% or more.

  The graph Y + in FIG. 14 shows the distribution of film thickness in the lens surface when the shielding plate B or shielding plate D has an installation error of about 10 mm in the Y direction in FIG. 12, and Y− in the −Y direction. It is. It can be seen that the worst value is only about 0.1%, and this also maintains the film thickness distribution in the plane of 98% or more.

  On the other hand, FIG. 15 is an example of a conventional technique in which a plurality of shielding plates AA to DD are arranged on the radiation centering on the revolution axis 15 of the substrate 10 of the vacuum film formation tank 11 without considering installation errors.

  FIG. 16 is a graph of the film thickness distribution in the lens surface by the shielding plates AA to DD according to the prior art when an installation error is given in the same manner as the graph of FIG.

  In the MM of FIG. 16, the distribution of the film thickness in the plane when there is no installation error of the shielding plates AA to DD is 98% or more and is controlled very uniformly. However, if an error of about 10 mm is given in the center direction and the Y direction of the vacuum film formation tank 11, the film thickness distribution in the former case deteriorates by 9% at the worst and becomes 91%, resulting in a non-uniform film thickness. In the latter case, the value itself is not large, but the film thickness distribution is deteriorated by about 1%, and a large error occurs as compared with the shielding plates A to D of the present embodiment. Therefore, the conventional shielding plate has poor manufacturing reproducibility.

  As described above, the shielding plate according to the present embodiment can form an optical thin film having a film thickness distribution in the lens surface controlled with high accuracy, and the film thickness in the surface with respect to installation errors. Therefore, film formation with good reproducibility of the film thickness distribution can be realized. Further, even if the installation error of the shielding plate is replaced with a minute change of the shielding plate, the same effect can be expected for the shape error of the shielding plate.

It is the schematic which shows an example of the vacuum evaporation system used in an Example. It is the schematic which shows the other example of the vacuum evaporation system used in an Example. FIG. 3 is a diagram showing the shape and installation position of the shielding plate of Example 1. 3 is a graph in which the distribution of film thickness shielded by the respective shielding plates A, B, C, and D in FIG. 2 is normalized by the film thickness at the center of the lens. 3 is a graph in which the distribution of the film thickness shielded by the respective shields A ′, B, C ′, and D in FIG. 2 is normalized by the film thickness at the center of the lens. 3 is a graph showing a film thickness distribution when a film is formed using the shielding plates A, B, C, and D in FIG. 2 and a film thickness distribution when an installation error is given to the shielding plate. 3 is a graph showing a film thickness distribution when a film is formed using the shielding plates A ′, B, C ′, and D of FIG. 2 and a film thickness distribution when an installation error is given to the shielding plate. FIG. 6 is a diagram showing the shape and installation position of a shielding plate of Example 2. FIG. 8 is a graph showing the film thickness shielded by each of the regions Ai and Ao of the shielding plate of FIG. FIG. 8 is a graph showing a film thickness distribution when a film is formed using the shielding plate A55 of FIG. 7 and a film thickness distribution when an installation error is given to the shielding plate. 8 is a graph showing a film thickness distribution when a film is formed using the shielding plate A64 of FIG. 7 and a film thickness distribution when an installation error is given to the shielding plate. 8 is a graph showing a film thickness distribution when a film is formed using the shielding plate A73 of FIG. 7 and a film thickness distribution when an installation error is given to the shielding plate. FIG. 6 is a diagram showing the shape and installation position of a shielding plate of Example 3. 13 is a graph in which the distribution of film thickness shielded by each of the regions A1 to D4 of the shielding plate in FIG. 12 is normalized by the film thickness at the center of the lens. 13 is a graph showing a film thickness distribution when a film is formed using the shielding plates A, B, C, and D in FIG. 12 and a film thickness distribution when an installation error is given to the shielding plate. It is a figure which shows the shape and installation position of the shielding board in a prior art example. 16 is a graph showing a film thickness distribution when a film is formed using the shielding plate of FIG. 15 and a film thickness distribution when an installation error is given to the shielding plate. It is a schematic diagram for demonstrating shielding by a shielding board. It is a flowchart for calculating the shape of a shielding board.

Explanation of symbols

10: Lens (member)
11: Vacuum film formation tank 12: Evaporation source 13: Vacuum pump 14: Rotating shaft 15: Revolving shaft 16: Shielding plate installation surface 17: Shielding plate 18: Film thickness monitor 19: Lens center

Claims (5)

A vacuum deposition apparatus,
A mechanism for supporting the member, rotating the member around a first axis passing through the center thereof, and revolving around a second axis different from the first axis;
An evaporation source disposed at a distance from the second axis and generating vapor deposition particles for forming a film;
N shields (where n is an integer equal to or greater than 2) which is disposed between the member rotated and revolved by the mechanism and the evaporation source and shields the deposition particles from adhering to the member being rotated and revolved. The board,
With
When Ai (where i = 1 to n) is the amount by which each of the n shielding plates shields the deposition particles from adhering to the rotating and revolving members, each of Ai satisfies the following equation: Thus, the vacuum deposition apparatus is characterized in that the shape of the n shielding plates is determined.
(A1 + A2 +... + An) × (1 / n−1 / (5n)) ≦ Ai ≦ (A1 + A2 +... + An) × (1 / n + 1 / (5n)) A vacuum deposition apparatus,
A mechanism for supporting the member, rotating the member around a first axis passing through the center thereof, and revolving around a second axis different from the first axis;
An evaporation source disposed at a distance from the second axis and generating vapor deposition particles for forming a film;
N shields (where n is an integer equal to or greater than 1) arranged between the member rotated and revolved by the mechanism and the evaporation source, and shields the deposition particles from adhering to the member being rotated and revolved. The board,
With
In each of the n shielding plates, a straight line connecting the intersection of the first axis of the surface of the member to which the vapor deposition particles adhere and the evaporation source intersects the surface of the shielding plate to which the vapor deposition particles adhere. The point is arranged so as to be divided into two regions by an orbital circle that moves with the revolution of the member,
Bi (where i = 1 to 2n) is the amount by which each of 2n regions of the n shielding plates divided by the orbital circle shields the deposition particles from adhering to the rotating and revolving members. Then, the shape of the n shielding plates is determined so that each of Bi satisfies the following formula.
(B1 + B2 +... + B2n) × (1 / (2n) −1 / (10n)) ≦ Bi ≦ (B1 + B2 +... + B2n) × (1 / (2n) + 1 / (10n)) A vacuum deposition apparatus,
A mechanism for supporting the member, rotating the member around a first axis passing through the center thereof, and revolving around a second axis different from the first axis;
An evaporation source disposed at a distance from the second axis and generating vapor deposition particles for forming a film;
N shields (where n is an integer equal to or greater than 1) arranged between the member rotated and revolved by the mechanism and the evaporation source, and shields the deposition particles from adhering to the member being rotated and revolved. The board,
With
In each of the n shielding plates, a straight line connecting the intersection of the first axis of the surface of the member to which the vapor deposition particles adhere and the evaporation source intersects the surface of the shielding plate to which the vapor deposition particles adhere. The point is divided into two regions by a plane including a straight line passing through the center of the orbital circle that moves with the revolution of the member and parallel to the second axis, and 2n generated in the n shielding plates by the division amount of Ci to shield the adhesion of the deposited particles to member is the rotation and revolution, respectively (where, i = 1 to 2n) to time, is the plane in which each Ci satisfies the following formula presence of regions As described above, the vacuum deposition apparatus is characterized in that the shape of the n shielding plates is determined.
(C1 + C2 +... + C2n) × (1 / (2n) −1 / (10n)) ≦ Ci ≦ (C1 + C2 +... + C2n) × (1 / (2n) + 1 / (10n)) Each of the divided 2n regions is further divided into two regions by the orbital circle,
When the amount by which each of the 4n regions divided by the plane and the orbit circle shields the deposition particles from adhering to the rotating and revolving member is Di (where i = 1 to 4n) The vacuum deposition apparatus according to claim 3, wherein the shapes of the n shielding plates are determined so that each of Di satisfies the following formula.
(D1 + D2 +... + D4n) × (1 / (4n) −1 / (20n)) ≦ Di ≦ (D1 + D2 +... + D4n) × (1 / (4n) + 1 / (20n)) A member manufacturing method comprising forming a film by attaching vapor deposition particles to a member using the vacuum evaporation apparatus according to any one of claims 1 to 4.

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