PVD mask structure and process

Abstract

The invention provides a PVD (Physical Vapor Deposition) mask structure and process, the PVD mask structure comprises a substrate, a mask plate with a mask window and a target gasification source which are sequentially distributed at intervals, the distance between two opposite surfaces of the mask plate and the substrate is greater than the thickness of a plating layer on the substrate, the shape of the mask window is similar to the shape of the plating layer, and the size of the mask window in any direction in the plane where the mask window is located is smaller than the size of the plating layer in the corresponding direction in the plane where the plating layer is located. According to the scheme, the mask and the substrate are distributed at intervals, and the distance between the two opposite faces of the mask and the substrate is larger than the thickness of the plating layer on the substrate. The problem that in the prior art, when a mask plate is attached to the surface of a substrate, the edge of a plating layer on the substrate adheres to a mask plate window, and consequently silver scraps occur when the mask plate is taken down can be solved.

Description

Technical Field

[0001] The present invention relates to the field of PVD technology, and particularly to a PVD mask structure and process. Background Art

[0002] The PVD mask process places a mask plate on a substrate, allowing only specific areas to be exposed for coating, thereby achieving selective coating of specific areas. The PVD technology includes various methods such as vacuum evaporation, sputtering plating, and ion plating, and these methods can all achieve patterned coating by adding a mask plate.

[0003] When using the patterned mask process to add weight to a small fossil quartz tuning fork (such as a tuning fork size of 1.6 mm × 1.0 mm or 1.2 mm × 1.0 mm or 1.0 mm × 0.8 mm), the problem of silver flakes often occurs. The problem of silver flakes will affect the vibration frequency of the small fossil quartz tuning fork. After analyzing the reasons, it is found that during the weight addition process, due to the adhesion of the coating in the weight addition area to the mask window, when the mask plate is removed after the weight addition is completed, the mask plate will break from the adhesion point with the coating, resulting in silver flakes. The problem of silver flakes has now become one of the reasons affecting the quality of the tuning fork. Summary of the Invention

[0004] Based on the problems existing in the above prior art, the present invention aims to solve the technical problem that when using the patterned mask process to add weight to a small fossil quartz tuning fork in the prior art, the problem of silver flakes often occurs.

[0005] The present invention provides a PVD mask structure, which includes a substrate, a mask plate with a mask window, and a target vaporization source that are sequentially spaced apart. The distance between the two opposite surfaces of the mask plate and the substrate is greater than the thickness of the coating on the substrate. Among them, the shape of the mask window is similar to the shape of the coating, and the size of the mask window in any direction in its plane is smaller than the size of the coating in the corresponding direction in its plane.

[0006] According to an embodiment of the present invention, the PVD mask structure further includes a collimator disposed between the mask plate and the target vaporization source. The collimator is used to allow only gaseous particles within a second offset angle β range that does not exceed a first offset angle α to pass through, where the first offset angle α is the maximum offset angle of the gaseous particles generated by the target vaporization source relative to the normal of the target vaporization source.

[0007] According to an embodiment of the present invention, the PVD mask structure further includes a spacer disposed between the substrate and the mask plate and having a through hole. Both side surfaces of the spacer are respectively attached to the substrate and the mask plate, and the size of the through hole in any direction in the plane where it is located is larger than the size of the mask window in the corresponding direction in the plane where it is located.

[0008] According to an embodiment of the present invention, the size of the through hole in any direction in the plane where it is located does not exceed 1.5 times the size of the mask window in the corresponding direction in the plane where it is located.

[0009] According to an embodiment of the present invention, the position of the collimator is adjustable in the direction of the line connecting the mask plate and the target vaporization source to adjust the second offset angle β.

[0010] According to an embodiment of the present invention, the second offset angle β does not exceed 20°.

[0011] The present invention also provides a PVD mask process, which is implemented based on the PVD mask structure.

[0012] According to an embodiment of the present invention, during the PVD mask process, the collimator needs to be continuously heated to prevent particles generated by the target vaporization source from adhering and depositing on the surface of the collimator.

[0013] According to an embodiment of the present invention, the PVD mask process is carried out in a vacuum environment.

[0014] According to an embodiment of the present invention, the PVD mask process is applied to the weighting process in the preparation of quartz tuning forks.

[0015] A PVD mask structure and process provided by the present invention have the following beneficial effects:

[0016] (1) By spacing the mask plate and the substrate, and making the distance between the two opposite surfaces of the mask plate and the substrate greater than the thickness of the coating on the substrate, when this solution is applied to the quartz tuning fork weighting process, it can avoid the problem of silver flakes occurring when removing the mask plate due to the adhesion of the coating edge on the substrate to the mask window when the mask plate is attached to the surface of the substrate (quartz tuning fork) in the prior art;

[0017] (2) By setting the mask window and the coating to have a similar shape, and making the size of the mask window in any direction in the plane where it is located smaller than the size of the coating in the corresponding direction in the plane where it is located, and by reasonably controlling the distance between the mask plate and the substrate, a coating with the expected size can be successfully obtained on the substrate. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of a PVD mask structure provided in Embodiment 1 of the present invention;

[0020] Figure 2 It is a first schematic structural diagram of a collimator in Embodiment 1 of the present invention;

[0021] Figure 3 It is a second schematic structural diagram of a collimator in Embodiment 1 of the present invention;

[0022] Figure 4 It is a schematic structural diagram of a PVD mask structure provided in Embodiment 2 of the present invention. Detailed Embodiments

[0023] The following description of each embodiment refers to the attached drawings to illustrate specific embodiments in which the present invention can be implemented.

[0024] Embodiment 1

[0025] The present invention provides a PVD mask structure, the structure of which is as Figure 1 shown, including a substrate 1, a mask plate 2 with a mask window 20, and a target vaporization source 3 that are distributed at intervals in sequence. The distance h between the two opposite surfaces of the mask plate 2 and the substrate 1 is greater than the thickness of the coating 10 on the substrate 1. Among them, the shape of the mask window 20 is similar to the shape of the coating 10, and the size of the mask window 20 in any direction in its plane is smaller than the size of the coating 10 in the corresponding direction in its plane.

[0026] When performing the PVD mask process, the target vaporization source 3 can generate gaseous particles, and only the gaseous particles passing through the mask window 20 can reach the surface of the substrate 1, thereby achieving selective deposition. Moreover, the shape and pattern of the mask window 20 determine the distribution of the gaseous particles on the surface of the substrate 1, thereby achieving patterned deposition.

[0027] Further, according to the Knudsen cosine distribution law, the distribution of gaseous particles generated by the target vaporization source 3 in space is related to the cosine of their emission angle, which means that most particles are approximately distributed in a conical shape along the normal direction of the target vaporization source 3. The proportion (density) of particles with a larger deviation angle is lower, that is, for the particles distributed in a conical shape, the density of the particles distributed on the outer side is lower. To ensure the uniformity of the thickness of the coating 1, the PVD mask structure further includes a collimator 4 disposed between the mask plate 2 and the target vaporization source 3. The collimator 4 is used to allow only gaseous particles within a second deviation angle β not exceeding a first deviation angle α to pass through, where the first deviation angle α is the maximum deviation angle of the gaseous particles generated by the target vaporization source 3 relative to the normal of the target vaporization source 3. Preferably, the second deviation angle β does not exceed 20°.

[0028] By providing the collimator 4 to screen out gaseous particles with a large incident angle, it is ensured that only gaseous particles close to the vertical direction (near the center of the cross-section of the cone) can reach the surface of the substrate 1, which can avoid a large thickness difference between the center and the edge of the coating 1, thereby improving the thickness uniformity of the coating 10.

[0029] In the embodiment of the present invention, let the maximum deviation angle of the particles allowed to pass through the mask plate 2 be θ (θ ≤ β), then the relative positional relationship between the mask plate 2 and the substrate 1 satisfies:

[0030]

[0031] wherein, H is the distance between the surface of the mask plate 2 close to the substrate 1 and the target vaporization source 3, h is the distance between the two opposite surfaces of the mask plate 2 and the substrate 1, and r1 and r2 are the radii of the mask window 20 and the coating 10 in the same direction in their respective planes.

[0032] In the PVD mask structure, for a simple mask pattern, such as a circle, the θ angle is a fixed value. Therefore, before starting the PVD mask process, we can calculate the corresponding H and h values according to the known θ angle and in combination with the sizes of the mask window 20 and the coating 10, so as to build a suitable PVD mask structure.

[0033] It should be noted that in a determined PVD mask structure, if the mask pattern is relatively complex, such as a polygon, since the sizes (i.e., r1) of the mask window 20 in different directions in its plane are different, the corresponding θ angles are also different. At this time, there will be multiple different θ angles in the same PVD mask structure. Therefore, when determining the θ angle, it needs to be determined according to the specific direction.

[0034] Furthermore, the position of the collimator 4 is adjustable in the direction of the line connecting the mask 2 and the target vaporization source 3 (the normal direction of the target vaporization source 3) to adjust the second offset angle β.

[0035] As a specific embodiment, the collimator 4 can be a thin plate with a collimation window in the center, such as Figure 2 shown, the collimation window forms a collimation area; in another embodiment, the collimator 4 can also be a thin plate with a number of collimation microholes in the center, such as Figure 3 shown, and a number of collimation microholes together constitute the collimation area.

[0036] Embodiment 2

[0037] Embodiment 2 also provides a PVD mask structure, the structure of which is as Figure 4 shown. The difference between Embodiment 2 and Embodiment 1 is that the PVD mask structure further includes a spacer 5 disposed between the substrate 1 and the mask 2 and having a through hole 50. The two side surfaces of the spacer 5 are respectively attached to the substrate 1 and the mask 2, and the size of the through hole 50 in any direction in its plane is larger than the size of the mask window 20 in the corresponding direction in its plane.

[0038] It is easy to understand that since the two side surfaces of the spacer 5 are respectively attached to the substrate 1 and the mask 2, in actual operation, the spacer 5 and the mask 2 can be sequentially stacked on the surface of the substrate 1, and the substrate 1 and the spacer 5 can support the mask 2. Compared with other support methods (such as setting a number of support blocks between the substrate 1 and the mask 2 for support), this solution can avoid the thin mask 2 being bent and deformed by gravity and generating indentations on the substrate 1 and the mask 2.

[0039] Furthermore, in order to avoid large deformation of the mask plate 2 due to gravity caused by the large size of the through hole 50, the size of the through hole 50 in any direction in its plane does not exceed 1.5 times the size of the mask window 20 in the corresponding direction in its plane.

[0040] Embodiment 3

[0041] Embodiment 3 provides a PVD mask process, which is realized based on the PVD mask structure described in Embodiment 1 or Embodiment 2. The PVD mask process is applied to the weighting process in the preparation of quartz tuning forks, especially the weighting process of small-sized quartz tuning forks.

[0042] Furthermore, to prevent the gaseous particles generated by the target vaporization source 3 from colliding with other particles and changing their movement paths, the PVD masking process is carried out in a vacuum environment.

[0043] According to an embodiment of the present invention, in the PVD masking process, when using the collimator 4 to control the movement path of gaseous particles, the gaseous particles may be deposited on the collimator. To improve this problem, during the PVD masking process, the collimator 4 needs to be continuously heated to prevent the particles generated by the target vaporization source 3 from adhering and depositing on the surface of the collimator 4.

[0044] It is easy to understand that heating the collimator 4 can increase the temperature of its surface, so that gaseous particles can obtain additional kinetic energy when contacting the collimator 4, which helps to reduce the adhesion and deposition of particles on the surface of the collimator 4. Moreover, for the particles that have been deposited on the surface of the collimator 4, heating can provide sufficient energy to make them re-volatilize into the gas phase, thereby reducing the accumulation of deposits on the surface of the collimator 4.

[0045] For the heating method of the collimator 4, heating can be carried out by means of resistance heating, induction heating or infrared heating, etc. In actual operation, which heating method to choose needs to consider the material, size and process requirements of the collimator 4, etc.

[0046] According to an embodiment of the present invention, during the PVD masking process, the collimator 4 also needs to be continuously heated, specifically including:

[0047] Before the target vaporization source 3 starts to generate gaseous particles, the collimator 4 is preheated to 150°C - 200°C, and after the target vaporization source 3 starts to generate gaseous particles, the collimator 4 is heated to 200°C - 450°C.

[0048] In summary, a PVD masking structure and process provided by the present invention, by distributing the mask plate and the substrate at intervals, and making the distance between the two opposite surfaces of the mask plate and the substrate greater than the thickness of the coating on the substrate. When this solution is applied to the quartz tuning fork weighting process, it can avoid the problem of silver flakes occurring when removing the mask plate due to the adhesion of the coating edge on the substrate and the mask window when the mask plate is attached to the surface of the substrate in the prior art; in addition, by setting the mask window and the coating to be similar in shape, and making the size of the mask window in any direction in its plane smaller than the size of the coating in the corresponding direction in its plane, by reasonably controlling the distance between the mask plate and the substrate, a coating with the expected size can be successfully obtained on the substrate.

[0049] It should be noted that although the present invention is disclosed above with specific embodiments, the above embodiments are not intended to limit the present invention. Those of ordinary skill in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A PVD mask structure, characterized in that, It includes a substrate, a mask plate with a mask window, and a target vaporization source that are sequentially and spaced apart. The distance between the two opposite surfaces of the mask plate and the substrate is greater than the thickness of the coating on the substrate. Among them, the shape of the mask window is similar to the shape of the coating, and the size of the mask window in any direction in its plane is smaller than the size of the coating in the corresponding direction in its plane.

2. The PVD mask structure according to claim 1, wherein It further includes a collimator disposed between the mask plate and the target vaporization source. The collimator is used to allow only gaseous particles within a second offset angle β that does not exceed a first offset angle α to pass through. Among them, the first offset angle α is the maximum offset angle of the gaseous particles generated by the target vaporization source relative to the normal of the target vaporization source.

3. The PVD mask structure according to claim 2, wherein, It further includes a spacer with a through-hole disposed between the substrate and the mask plate. The two side surfaces of the spacer are respectively attached to the substrate and the mask plate, and the size of the through-hole in any direction in its plane is greater than the size of the mask window in the corresponding direction in its plane.

4. The PVD mask structure according to claim 3, wherein, The size of the through-hole in any direction in its plane does not exceed 1.5 times the size of the mask window in the corresponding direction in its plane.

5. The PVD mask structure according to claim 2, wherein, The position of the collimator in the direction of the connection line between the mask plate and the target vaporization source is adjustable to adjust the second offset angle β.

6. The PVD mask structure according to claim 2, characterized in that, The second offset angle β does not exceed 20°.

7. A PVD mask process, characterized in that, It is implemented based on the PVD mask structure according to any one of claims 1 to 6.

8. The PVD mask process according to claim 7, wherein, The PVD mask process is carried out in a vacuum environment.

9. The PVD mask process according to claim 7, characterized in that, During the PVD mask process, the collimator needs to be continuously heated to prevent the particles generated by the target vaporization source from adhering and depositing on the surface of the collimator.

10. The PVD mask process according to claim 7, wherein The PVD mask process is applied to the weighting process in the preparation of quartz tuning forks.

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