A PVD coating device

Abstract

The utility model discloses a kind of PVD coating devices, including target material, for releasing positive charged target material particles after being bombarded;Rotary platform, plating substrate is provided thereon, and rotates at uniform speed along fixed rotation direction;Plating substrate;And negative voltage plate, set in the interior of rotary platform, the negative voltage plate is the annular structure compatible with plating substrate surface.The utility model is through the multiple concentric negative voltage plate of negative electricity, its each unit insulation and can independently control electric field: by positive and negative charge attraction constraint sputtering direction to plating substrate, promote film forming speed and target material utilization rate;Borrow partition electric field compensation film thickness difference caused by rotation, improve uniformity;While reducing the adhesion of anti-attachment component material, reduce maintenance frequency.The utility model promotes film forming efficiency and quality, improves thin film process yield, applicable to semiconductor photomask substrate PVD film forming process.

Description

Technical Field

[0001] This utility model relates to the semiconductor field, and more particularly to a PVD coating apparatus. Background Technology

[0002] In the manufacturing process of semiconductor photomask substrates, PVD film deposition is the core step in forming functional thin films such as metal conductive films and insulating films. Its process performance is directly related to the production capacity, product yield and manufacturing cost of photomask substrates. Currently, the PVD film deposition apparatus used in the industry for semiconductor photomask substrates generally adopts the following structure and working mode: The core components of the apparatus include a target material, positively charged target material after sputtering, a divergent sputtering direction, a composite platform (which can drive the substrate to be coated to rotate) that has both rotational support and anti-attachment functions, a rotation direction, the substrate to be coated, positioning components for fixing the substrate to be coated, and an independent anti-attachment plate; its working principle is as follows: external energy bombards the target material, causing the target material to release positively charged target material. This positively charged target material diffuses in a divergent direction, and some of the material is deposited on the surface of the substrate to be coated to form the target thin film. The excess target material that is not deposited on the substrate to be coated is attached to the surface of the composite platform that has both rotational support and anti-attachment functions and the independent anti-attachment plate; at the same time, the composite platform that has both rotational support and anti-attachment functions drives the substrate to rotate along the set rotation direction in an attempt to optimize the thickness uniformity of the thin film.

[0003] However, the aforementioned existing PVD film formation devices have unavoidable technical defects in practical applications, specifically manifested as follows: Slow film formation rate: Because the sputtering direction of the positively charged target material is divergent, a large amount of target material cannot be directed to the substrate to be coated, but diffuses to the non-film formation area of ​​the cavity, resulting in a very low proportion of target material actually deposited on the surface of the substrate to be coated, which directly causes low film formation efficiency. Low target utilization: The divergent sputtering direction means that more than half of the target material does not participate in the film formation of the substrate, but instead adheres to the surface of the anti-sputtering components, resulting in serious waste of target material and significantly increasing the cost of raw material procurement. High maintenance frequency and high maintenance costs: The surface of the anti-attachment plate and the composite platform that combines rotation support and anti-attachment functions has an upper limit on the adhesion thickness due to the continuous adhesion of excess target material. When the thickness exceeds the threshold, the material is prone to peeling off, resulting in particulate contamination, which in turn affects the film quality. Therefore, the above-mentioned anti-attachment related components need to be disassembled and cleaned frequently, and the cleaning methods are mostly outsourced to heavy industry. This not only leads to long equipment downtime and large capacity loss, but also increases maintenance costs. Poor film thickness uniformity: Although the composite platform with both rotation support and anti-stick function can drive the substrate to be coated to rotate, the rotation process can easily cause concentric circular thickness differences on the surface of the substrate to be coated. Existing devices lack effective means to compensate for this difference, and cannot meet the stringent technical requirements of semiconductor photomask substrates for film thickness tolerance.

[0004] To address some of the aforementioned issues, existing technologies have attempted improvements, as detailed below: Patent CN202310256789.1 discloses a technical solution to improve the thermal stability of the target by optimizing the target cooling channel. Its core improvement is to avoid the sputtering rate fluctuation caused by the target overheating. However, it does not involve the design of "guiding the target material to be deposited in a directional manner through a negative electric field", and still cannot solve the problems of low target utilization and slow film formation speed. Patent CN202221876543.2 discloses an anti-attachment plate with a ceramic coating, which extends its service life by improving the wear resistance of the anti-attachment plate. However, it only focuses on improving the material of the anti-attachment plate itself and does not fundamentally reduce the amount of excess target material attached (it does not involve electric field guiding the directional deposition of target material) nor solve the core defect of uneven film thickness. Patent CN202110987654.3 discloses a method for optimizing film uniformity by adjusting the rotation speed of a rotating platform in real time. However, it only attempts to improve uniformity by adjusting mechanical motion parameters, which cannot compensate for the concentric circle thickness difference caused by the rotation motion itself. Furthermore, it does not involve the electric field control of the sputtering direction of the target material, and thus cannot solve the problem of low film formation efficiency.

[0005] Therefore, there is an urgent need to propose a new PVD film formation technology to overcome the existing technological bottlenecks. Utility Model Content

[0006] This invention incorporates a negatively charged multi-concentric circle negative voltage plate into the device. Each concentric circle unit of the negative voltage plate is mutually insulated and its electric field strength can be independently adjusted. On one hand, the attraction between the negative electric field and the positively charged target material constrains the divergent sputtering direction to a directional path focused towards the substrate, increasing the target deposition ratio to accelerate film formation and improve target utilization. On the other hand, the partitioned electric field compensates for differences in target material reception in different areas during substrate rotation, solving the problem of uneven film thickness. Furthermore, the coordinated operation of the negative voltage plate and the rotating platform reduces the amount of anti-adhesion material adhering to the plate, lowering the maintenance frequency.

[0007] This invention provides a PVD coating apparatus, the sputtering chamber of which includes: Target material, used to release positively charged target material particles after being bombarded; A rotating platform on which a substrate to be plated is mounted and rotates at a constant speed along a fixed rotation direction; The substrate to be plated; and A negative voltage plate is disposed inside the rotating platform, and the negative voltage plate is a ring structure adapted to the surface of the substrate to be plated.

[0008] In one embodiment of this utility model, the negative voltage plate is used to connect to an external power source to generate a negative electric field, so as to guide the positively charged target material particles to move directionally toward the substrate to be plated.

[0009] In one embodiment of this utility model, the negative voltage plate is provided with multiple independent concentric circular units, each concentric circular unit being mutually insulated, for independently controlling the electric field intensity of each region to form differentiated electric field distribution regions.

[0010] In one embodiment of this utility model, an anti-attachment plate is provided on the rotating platform near the substrate to receive target material particles that have not been deposited on the substrate.

[0011] In one embodiment of this utility model, the surface of the rotating platform is provided with an anti-adhesion coating or a smooth structure to receive positively charged target material that has not been deposited on the substrate to be plated.

[0012] In one embodiment of this utility model, the rotating platform is provided with a plurality of fixed positioning pins to make the center of the substrate to be plated completely coincide with the rotation center of the rotating platform.

[0013] In one embodiment of this utility model, an anti-attachment plate is also included, which is disposed on the inner wall of the sputtering cavity to receive the target material that diffuses toward the wall of the sputtering cavity.

[0014] In one embodiment of this utility model, the rotation direction and speed of the rotating platform are matched with the sputtering direction and sputtering speed of the target material to ensure that the amount of target material particles received at each point on the surface of the substrate is consistent for each rotation.

[0015] This utility model has the following beneficial effects: (1) The negative electric field generated by the negative voltage plate forms a directional attraction with the positively charged target material, which constrains the originally divergent sputtering direction into a directional path that focuses on the substrate to be coated, greatly increasing the ratio of target material deposited on the substrate to be coated, directly accelerating the film formation speed, shortening the film formation cycle of a single substrate, and increasing the production capacity of the equipment per unit time.

[0016] (2) The negative voltage plate is designed as multiple concentric circular units that are insulated from each other. Each unit can independently adjust the electric field strength. During the rotation of the substrate, its different annular regions will pass through the differentiated electric field region of the negative voltage plate in sequence. The difference in the amount of target material received in each region is compensated by the electric field strength, so that the film thickness tolerance meets the stringent requirements of the semiconductor photomask substrate, and the overall yield of the thin film process is significantly improved.

[0017] (3) In this utility model, more target material is deposited on the substrate to be plated, the amount of excess material attached to the surface of the anti-sticking plate is greatly reduced, the growth rate of the adhesion thickness of the anti-sticking plate material slows down, which not only reduces the risk of material peeling and defects, but also extends the cleaning cycle of the anti-sticking plate, reduces the cost and time consumption of outsourced heavy work, increases the effective production time of the equipment, and further improves the production capacity and economy. Attached Figure Description

[0018] Figure 1 A schematic diagram of a PVD coating apparatus according to an embodiment of the present invention is shown. Detailed Implementation

[0019] In the following description, the present invention is described with reference to various embodiments. However, those skilled in the art will recognize that the embodiments may be practiced without one or more specific details or with other alternatives and / or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail so as not to obscure the inventive aspects of the present invention. Similarly, for illustrative purposes, specific quantities, materials, and configurations are set forth to provide a comprehensive understanding of embodiments of the present invention. However, the present invention is not limited to these specific details.

[0020] In this utility model, the various embodiments are merely intended to illustrate the solution of this utility model and should not be construed as limiting.

[0021] In this specification, references to "an embodiment" or "this embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the present invention. The phrase "in one embodiment" appearing throughout this specification does not necessarily refer to all of the same embodiment.

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 A schematic diagram of a PVD coating apparatus according to an embodiment of the present invention is shown.

[0024] like Figure 1 As shown, in one embodiment of this utility model, the PVD coating apparatus includes: The target material 201, as the core component for material supply in the PVD film deposition process, is specifically designed to provide the target material source for the semiconductor photomask substrate film deposition process, and is a fundamental prerequisite for achieving thin film deposition. The target material 201 possesses the physical property of being bombarded by external energy. After being bombarded, it can stably release positively charged target material particles, and the composition and purity of the released material must match the material requirements of the semiconductor photomask substrate for the thin film. It is installed in a specific area of ​​the film deposition cavity and is positioned opposite to the substrate 206 to be deposited, ensuring that the released positively charged target material 202 can move towards the substrate 206 under the guidance of the subsequent electric field, forming an effective sputtering path.

[0025] The positively charged target material 202 has stable positive electric properties, which is the key physical basis for realizing electric field-guided directional deposition. Its charge intensity needs to be matched with the electric field intensity of the negative voltage plate 209 to ensure that it can be effectively attracted. In the initial sputtering state, it can diffuse in multiple directions. Under the action of the electric field of the negative voltage plate 209, the sputtering direction 203 can be controlled to focus on the substrate 206 to be deposited, which greatly increases the deposition rate on the surface of the substrate and reduces diffusion loss to other areas of the cavity.

[0026] The rotating platform 204 adopts an integrated structure of "rotating platform + anti-attachment plate," which combines support, rotation drive, and protection functions, eliminating the need for separate rotating platforms and anti-attachment components and simplifying the internal structure of the cavity. The anti-attachment plate is installed in the "core film formation area" of the film formation cavity, directly surrounding the substrate 206. Its position is closely related to the substrate and it needs to rotate synchronously with the rotating platform. Its function area is concentrated below and around the substrate, mainly catching the "excess target material near the substrate" that diffuses from the sputtering direction 203 and has not been deposited onto the substrate. The surface of the rotating platform 204 has mounting positions that are compatible with the fixing pins 207. The fixing pins 207 achieve precise positioning and stable support for the substrate 206, ensuring that the substrate 206 does not shift or wobble during rotation. The positioning accuracy meets the stringent requirements for semiconductor photomask film formation.

[0027] The rotating platform 204 can rotate at a constant speed along the rotation direction 205. The rotation speed can be adjusted according to the film deposition process parameters (such as film thickness and film deposition speed), driving the substrate 206 to rotate synchronously, so that each area of ​​the substrate can uniformly contact the positively charged target material 202.

[0028] The surface of the rotating platform 204 has an anti-adhesion coating or a smooth structure, which can receive a small amount of positively charged target material 202 that has not been deposited on the substrate 206, thus preventing the target material from directly adhering to the cavity wall. At the same time, due to the focusing optimization of the sputtering direction 203, the amount of target material adhering to its surface is significantly reduced, the growth rate of the adhesion thickness is slowed down, and the risk of material peeling is reduced.

[0029] The substrate 206, serving as the direct carrier for PVD film deposition on the semiconductor photomask substrate, is the core component for the final formation of the functional thin film. The substrate material, flatness, and cleanliness must meet industry standards for semiconductor photomask manufacturing. The substrate 206 is connected to the rotating platform 204 via a fixing pin 207. After installation, the substrate surface is perpendicular to the sputtering direction 203 or at a specific angle (set according to the film deposition process requirements), ensuring that the effective film deposition area is completely covered by the sputtering direction 203.

[0030] The surface of the substrate 206 can form a good bond with the positively charged target material 202, ensuring that the deposited film is not easy to fall off or crack. At the same time, the thermal and chemical stability of the substrate must be adapted to the vacuum and high temperature (or low temperature) environment of the PVD film formation process, so as not to cause deformation or material deterioration.

[0031] The number and installation position of the fixing and positioning pins 207 need to be designed according to the size and shape of the substrate 206 to be plated. Typically, there are 3 to 4 pins, symmetrically distributed, to ensure that after the substrate is fixed, the center of the substrate completely coincides with the rotation center of the rotating platform 204, controlling the positioning error to the micrometer level and avoiding uneven film formation due to center offset. They are made of rigid metal or high-temperature resistant non-metallic materials, with a columnar or pin-shaped structure, possessing sufficient mechanical strength to withstand the weight of the substrate 206 and the centrifugal force during rotation.

[0032] The anti-attachment plate 208 is installed in the non-film-forming area inside the film-forming cavity (such as the cavity sidewall and the non-target area at the top). Together with the rotating platform 204, it forms the cavity protection system. The anti-attachment plate 208 is usually annular, plate-shaped, or irregularly shaped to fit the cavity contour. It has a smooth surface and low adhesion, which can block the diffusion of the positively charged target material 202 into the non-film-forming area of ​​the cavity, thus preventing the target material from adhering to the cavity wall and causing contamination. At the same time, it can be disassembled and cleaned periodically. The material must be resistant to chemical reagents or physical abrasion during the cleaning process and has strong reusability.

[0033] Although various embodiments of the present invention have been described above, it should be understood that they are presented by way of example only and not as limitations. It will be apparent to those skilled in the art that various combinations, modifications, and alterations can be made thereto without departing from the spirit and scope of the present invention. Therefore, the breadth and scope of the present invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should be defined solely by the appended claims and their equivalents.

Claims

1. A PVD coating apparatus, characterized in that, Its sputtering cavity includes: Target material, used to release positively charged target material particles after being bombarded; A rotating platform on which a substrate to be plated is mounted and rotates at a constant speed along a fixed rotation direction; The substrate to be plated; and A negative voltage plate is disposed inside the rotating platform, and the negative voltage plate is a ring structure adapted to the surface of the substrate to be plated.

2. The PVD coating apparatus according to claim 1, characterized in that, The negative voltage plate is used to connect to an external power source to generate a negative electric field, so as to guide the positively charged target material particles to move directionally toward the substrate to be plated.

3. The PVD coating apparatus according to claim 2, characterized in that, The negative voltage plate is provided with multiple independent concentric circular units, which are mutually insulated from each other, and are used to independently control the electric field intensity in each region to form differentiated electric field distribution areas.

4. The PVD coating apparatus according to claim 1, characterized in that, An anti-attachment plate is provided on the rotating platform near the substrate to catch target material particles that have not been deposited on the substrate.

5. The PVD coating apparatus according to claim 1, characterized in that, The surface of the rotating platform is provided with an anti-adhesion coating or a smooth structure to receive positively charged target material that has not been deposited on the substrate to be plated.

6. The PVD coating apparatus according to claim 1, characterized in that, The rotating platform is equipped with multiple fixed positioning pins to ensure that the center of the substrate to be plated is completely aligned with the rotation center of the rotating platform.

7. The PVD coating apparatus according to claim 1, characterized in that, It also includes a shielding plate, which is installed on the inner wall of the sputtering chamber to receive the target material that diffuses toward the wall of the sputtering chamber.

8. The PVD coating apparatus according to claim 1, characterized in that, The rotation direction and speed of the rotating platform are matched with the sputtering direction and speed of the target material to ensure that the amount of target material particles received at each point on the surface of the substrate is consistent for each rotation.

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