Patent Application
20240376591
Embodiments of the present invention generally relate to semiconductor substrate processing equipment. More particularly, the present disclosure relates to a method and apparatus for securing a substrate on a substrate support.
Physical vapor deposition (PVD) is a widely used process for creating thin films on substrates in a variety of industrial and research applications. The process involves the use of physical effects, such as evaporation or ion bombardment, to force source atoms into a gaseous phase and then deposit them on a substrate to form a thin film. The PVD process typically involves heating or ionizing the source material, which is then directed toward the substrate in a vacuum chamber. The substrate is supported in the chamber on a support member. The substrate is placed on, and secured to, the upper surface of the support member prior to the deposition or etch process.
The substrate may be biased, or electrically charged, to accelerate the ions toward its surface, where they deposit and form a thin film. During the PVD process, it is essential to secure the substrate in place to ensure that it remains stable and does not move or shift during the deposition process.
Clamps may be used in PVD chambers to secure the substrate to the support member. The clamps are designed to provide a tight grip on the substrate to prevent any unwanted movement that could affect the uniformity of the deposited film. However, care must be exercised when securing a substrate so that the substrate is not damaged by the clamp. Clamps may be positioned both laterally and vertically relative to the substrate to reduce the risk of damage under the weight of the clamp. Even with this arrangement, clamps may exert too much force when securing the substrate that the substrate may be damaged.
Further, the use of gaskets in clamps to secure the substrate can contribute to the contamination of the substrate. Gaskets can become contaminated with impurities such as hydrocarbon molecules from poorly trapped oil diffusion pumps, organic gaskets, or grease used on gaskets. This contamination can lead to the release of impurities back into the PVD chamber during the deposition process, which can then contaminate the substrate.
Moreover, the use of clamps in PVD chambers could also contribute to the shadowing effect, a phenomenon where the deposition of material on a substrate is blocked by an object in the path of the vapor stream, resulting in a shadow being cast on the substrate. The clamps themselves can create a physical barrier that blocks the vapor stream and causes the shadowing effect. Additionally, the size and position of the clamps can also affect the shadowing effect by casting shadows on the substrate and blocking the deposition of material in certain areas.
Accordingly, there is a need for an improved apparatus and method of securing a substrate to a substrate support during a PVD process.
Embodiments described herein generally relate to systems and methods used for forming tungsten features in a semiconductor device. More particularly, embodiments herein provide for processes and methods to depassivate a tungsten passivation layer to allow faster tungsten growth in a subsequent tungsten growth step.
In an embodiment, a clamp assembly for securing a substrate in a processing chamber is provided. The clamp assembly includes a main clamp, a sub-clamp having a tapered inner edge, a gasket disposed within the sub-clamp, the gasket being proximate to the tapered inner edge having a gasket contact surface configured to contact a substrate, and a leaf spring secured to the sub-clamp by at least one of a plurality of fasteners.
In another embodiment, a clamp assembly configured to secure a substrate to the substrate support is provided. The clamp assembly has a main clamp, a sub-clamp having an inner edge that is tapered, a gasket disposed within a sub-clamp recess of the sub-clamp, a leaf spring in direct contact with the gasket and the main clamp, and a plurality of fasteners.
In yet another embodiment, a clamp assembly for securing a substrate to a substrate support is provided. The clamp assembly includes a main clamp, a sub-clamp having a tapered inner edge, the sub-clamp secured to the main clamp by a fastener, a gasket having a gasket contact surface, and a compression spring disposed coaxially about the fastener.
So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of the scope of the disclosure, as the disclosure may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
Embodiments herein are generally directed to semiconductor substrate processing equipment. More particularly, the present disclosure relates to a method and apparatus for securing a substrate on a substrate support during physical vapor deposition. Embodiments provided herein include improved systems and methods for securing a substrate to a substrate support using a clamp assembly.
During physical vapor deposition (PVD), clamps are essential to secure the substrate, preventing unwanted movement that could result in non-uniform deposition. However, clamps may exert too much force when securing the substrate which leads to substrate damage. Clamps may also contribute to the shadowing effect within a chamber as the clamps may be an obstacle in the vapor stream. The size and position of the clamps may block deposition of material in areas of the substrate where deposition is desired. Further, gaskets used in clamps to secure the substrate may contribute to contamination of the substrate. Gaskets may become contaminated with impurities which may be released into the PVD chamber and onto the substrate.
Accordingly, the present disclosure provides a technical solution to the problems described above by providing systems and methods for improved securing of a substrate during a PVD process by using a clamp assembly that includes a main clamp, a sub-clamp, and different spring arrangements. The sub-clamp is secured to the main clamp either directly, via the spring, or a combination of both. The sub-clamp includes a gasket comprising of a polymer material such as polyetheretherketone (PEEK) with a contact surface that contacts the substrate. The contact surface of the gasket is wide enough to reduce the pressure placed on the substrate when securing it while maintaining the force required to maintain the position of the substrate on the substrate support. The PEEK material of the gasket also reduces the contamination that the gasket contributes to the substrate surface. The sub-clamp also includes a tapered nose on an inner edge closest to the substrate. The tapered nose on the inner edge reduces the shadowing effect on the edges of the substrate, prevents cracking and arcing of the sub-clamp with the substrate, and reduces the amount of deposition on the gasket.
The sub-clamp 120 includes a gasket 130 disposed within the sub-clamp 120 proximate to the tapered inner edge 122 that is configured to contact the substrate 102 when the sub-clamp 120 is engaged. The inner edge 122 is tapered and rounded such that the inner edge 122 does not contact the substrate 102 when the sub-clamp 120 is engaged in securing the substrate 102. The inner edge 122 leaves a gap between the inner edge 122 and the substrate 102 that is small, such as between about 0.1 mm and about 0.5 mm, such as between about 0.2 mm and about 0.4 mm, such as about 0.3 mm, which protects the gasket 130 from unnecessary deposition on the gasket 130, reducing gasket particle contamination and extending the life of the gasket 130. The tapered inner edge 122 helps avoid arcing and reduces the shadowing effect of the clamp assembly 100 during the PVD process.
The gasket 130 comprises a polymer such as PEEK and includes a gasket contact surface 132 such that the width of the gasket contact surface 132 is greater than the cross-sectional height of the gasket 130. The increased width of the gasket contact surface 132 provides a wider contact surface for the substrate 102. This increased contact surface allows for the force applied to the substrate 102 to remain the same while substantially reducing the pressure applied to the substrate 102. This reduced pressure prevents cracking or other damage to the substrate 102 by the clamp assembly 100. Additionally, the polymer composition of the gasket 130 reduces particle generation during the deposition process.
The main clamp 110 includes a slot 112 corresponding to the shape of the leaf spring 140. When the main clamp 110 is lowered onto the substrate support 104 to secure the substrate 102, the sub-clamp 120 engages the substrate 102 via the gasket 130 and the leaf spring 140 deforms to allow the sub-clamp 120 to displace vertically.
When the gasket 130 contacts the substrate 102, the substrate 102 places an upward force on the gasket 130 and the sub-clamp 120, causing the sub-clamp 120 to displace vertically upward. As the sub-clamp 120 displaces, the sub-clamp 120 displaces upward causing the leaf spring 140 deform relative to the slot 112. As the sub-clamp 120 continues to move upward, the leaf spring 140 then applies a reactive spring force downward through the fastener 106 to the sub-clamp 120 and the gasket 130 and subsequently to the substrate 102. This reactive spring force then secures the substrate 102 to the substrate support 104. The reactive spring force is strong enough to secure the substrate 102 without damaging it. The leaf spring 140 along with the sub-clamp 120 allows for the clamp assembly 100 to adjust to different thickness substrates, such as between about 0.2 mm to about 1.2 mm. The height of the clamp assembly 100 is also reduced by using the sub-clamp 120 and leaf spring 140 configuration, with heights about 5.5 mm or less from the substrate surface, to allow more uniform deposition on the substrate 102 near the clamp assembly 100 (e.g., the inner edge 122).
When the gasket 130 contacts the substrate 102, the substrate 102 places an upward force on the gasket 130 and the sub-clamp 120, causing the sub-clamp 120 to displace vertically upward. As the sub-clamp 120 displaces, the sub-clamp 120 displaces upward causing the leaf spring 140 deform relative to the slot 112. As the sub-clamp 120 continues to move upward, the leaf spring 140 then applies a reactive spring force downward through the fastener 106 to the sub-clamp 120 and the gasket 130 and subsequently to the substrate 102. This reactive spring force then secures the substrate 102 to the substrate support 104. The reactive spring force is strong enough to secure the substrate 102 without damaging it.
As shown in
When the gasket 230 contacts the substrate 102, the substrate 102 places an upward force on the gasket 230 and the sub-clamp 220, causing the sub-clamp 220 to displace vertically upward. As the sub-clamp 220 displaces, the bushing 244 slides upward through the main clamp aperture 214 causing the leaf spring 240 to contact the back of the slot 212. As the bushing 244 continues to slide upward, the leaf spring 240 then applies a reactive spring force downward through the fastener 106 to the sub-clamp 220 and the gasket 230 and subsequently to the substrate 102. This reactive spring force then secures the substrate 102 to the substrate support 104. The reactive spring force is strong enough to secure the substrate 102 without damaging it.
In
The sub-clamp 320 includes a sub-clamp recess 324 proximate to the gasket 330. The sub-clamp recess 324 allows the gasket 330 to displace upward into the sub-clamp 320 and deform the leaf spring 340 with pressure from the upward displacement. This sub-clamp recess 324 allows for a greater degree of motion for the gasket 330 to displace while maintaining the tapered inner edge 322 of the sub-clamp near the substrate 102.
The gasket 330 includes a gasket slot 332 along an outer edge proximate the tapered inner edge 322 and closest to the substrate 102. The gasket slot 332 allows for reduced gasket 330 weight, resulting in less pressure applied to the substrate 102. The gasket 330 may also include a gasket groove 334 on a lower surface of the gasket 330. The gasket groove 334 recessed into the gasket 330, allows the gasket 330 to maintain the desired gasket contact surface with the substrate 102 while reducing the weight of the gasket 330 to reduce the pressure applied to the substrate 102.
Advantageously, the only weight imposed on the substrate 102 is the weight of the gasket 330 and any reactive spring force applied by the leaf spring 340 through the gasket 330. This removes unnecessary pressure on the edges of the substrate 102, reducing potential damage. Further, as the gasket 330 and the leaf spring 340 are the only components that displace in the clamp assembly 300, the height of the clamp assembly 300 remains the same, reducing the shadowing effect imposed by the clamp assembly 300 during deposition. Additionally, the use of the leaf spring 340 reduces particle generation while using the clamp assembly 300.
The main clamp 410 includes a slot 412 to allow access to the fastener 106 and the leaf spring 440 from below and a main clamp recess 414 adjacent to the gasket 430. The main clamp recess 414 is configured to receive a portion of the gasket 430 and allow motion of the gasket 430 within the main clamp recess 414. A portion of the leaf spring 440 protrudes into the main clamp recess 414 and is in direct contact with the gasket 430.
The gasket 430 includes an oblong portion 430a extending from one side of a cylindrical portion 430b and a hooked oblong portion 430c extending coaxially from an opposing side of the cylindrical portion 430b. The cylindrical portion 430b rests on a main clamp groove 416 such that the cylindrical portion 430b may rotate about the main clamp groove 416. An opposing side of the cylindrical portion 430b contacts a sub-clamp groove 426 and at least partially supports the sub-clamp 420. The sub-clamp 420 includes a sub-clamp recess 424 proximate to a hooked oblong portion 430c of the gasket 430 and an inner edge 422 of the sub-clamp 420.
When the clamp assembly 400 engages with the substrate 102, the substrate 102 contacts a surface of the hooked oblong portion 430c of the gasket 430, causing the gasket 430 to rotate about the main clamp groove 416 and the sub-clamp groove 426. This rotation causes the oblong portion 430a to exert a downward force on the leaf spring 440, deforming the leaf spring 440 in relation to the rotation, and resulting in the leaf spring 440 exerting an upward reactive spring force on the oblong portion 430a. The hooked oblong portion 430c also rotates upward into the sub-clamp recess 424 as a result of the applied pressure from the substrate 102. The rotation of the gasket 430 as a result of the force applied by the substrate 102 ceases when either the leaf spring 440 exerts a reactive spring force equal to the substrate force or when the hooked oblong portion 430c contacts the surface of the sub-clamp recess 424.
The leaf spring 440 configuration along with the rotating gasket 430 and recessed sub-clamp 420 allows for substrates 102 of varying thicknesses to be secured while minimizing the clamp assembly 400 profile as the sub-clamp 420 does not displace upward, reducing the shadowing effect by the clamp assembly 400.
The sub-clamp 520 includes an inner edge 522 closest to the substrate 102 that is tapered. The inner edge 522, when the clamp assembly 500 is engaged with the substrate 102, produces a small gap between the sub-clamp 520 and the substrate 102, protecting the gasket 530 from exposure to the deposition process, thus reducing gasket particle contamination and prolonging the life of the gasket 530.
As the substrate 102 applies a pressure on the gasket contact surface 532, the gasket 530 displaces the sub-clamp 520 and the fastener 560 such that the fastener 560 slides through the aperture 514 causing the compression spring 550 to contact a back surface 516 of the main clamp recess 512. As the compression spring 550 contacts the back surface 516, the compression spring 550 becomes increasingly compressed as the fastener 560 displaces upward through the aperture 514 resulting in an increasingly stronger reactive spring force applied to the distal portion of the fastener 560 by the compression spring 550. The displacement of the fastener 560 ceases when the reactive spring force is equal to the pressure applied by the substrate 102 to the gasket contact surface 532.
The sub-clamp 620 includes an inner edge 622 closest to the substrate 102 that is tapered. The inner edge 622, when the clamp assembly 600 is engaged with the substrate 102, produces a small gap between the sub-clamp 620 and the substrate 102, protecting the gasket 630 from exposure to the deposition process, thus reducing gasket particle contamination and prolonging the life of the gasket 630.
The gasket 630 is secured into a sub-clamp recess 624 near the inner edge 622 such that a gasket contact surface 632 protrudes from the sub-clamp recess 624. The gasket 630 is shaped such that the weight of the gasket 630 is minimized, reducing pressure through the gasket contact surface 632 onto the substrate 102.
The main clamp 610 includes a main clamp recess 612 that houses the compression spring 640. The compression spring 640 is coaxially coupled to the fastener 660 via a fastener slot 662 at a distal portion of the fastener 660. The fastener 660 protrudes through the main clamp recess 612 and into the body of the sub-clamp 620.
When the clamp assembly 600 engages with the substrate 102, the substrate 102 applies a force through the gasket contact surface 632 which upwardly displaces the gasket 630, the sub-clamp 620, and the fastener 660. This displacement compresses the compression spring 640, resulting in a reactive spring force applied to the fastener 660, the sub-clamp 620, and the gasket 630. The upward displacement of the fastener 660, sub-clamp 620, and gasket 630 ceases when the reactive spring force is equal to the force applied by the substrate 102. This reactive spring force secures the substrate 102 to the substrate support 104 without damaging the substrate 102.
A cross-sectional view of a clamp assembly 700 is shown in
The second fastener 762 secures the gasket 730 to the sub-clamp 720. The compression spring 750 is concentrically aligned to the second fastener 762 and contacts the gasket 730 through a gasket recess 734 and the sub-clamp 720 through a sub-clamp recess 726. The sub-clamp 720 includes a sub-clamp groove 724 matching the curvature of a hooked portion 736 of the gasket 730.
As the clamp assembly 700 engages with the substrate 102, the gasket 730 contacts the substrate 102 via a gasket contact surface 732. The force applied by the substrate 102 displaces the gasket 730 upward, applying a compressive force to the compression spring 750. The compression spring 750 subsequently applies a reactive spring force to the gasket 730 via the gasket recess 734. The gasket 730 displacement ceases either when the reactive spring force matches the force applied by the substrate 102 or when the gasket 730 contacts the sub-clamp groove 724. The clamp assembly 700 limits the weight of the assembly in contact with the substrate 102 to be only the weight of the gasket 730, reducing unnecessary pressure on the substrate 102 at the gasket contact surface 732.
The present disclosure provides systems and methods for improved securing of a substrate during a PVD process. More specifically, the present disclosure provides a clamp assembly that includes a main clamp, a sub-clamp, and different spring arrangements. The sub-clamp may be secured to the main clamp either directly, via the spring, or a combination of both. The sub-clamp includes a gasket comprising of a polymer material such as PEEK with a contact surface that contacts the substrate. The contact surface of the gasket is wide enough to reduce the pressure placed on the substrate when securing it while maintaining the force required to maintain the position of the substrate on the substrate support. The PEEK material of the gasket also reduces the contamination that the gasket contributes to the substrate surface. The sub-clamp also includes a tapered nose on an inner edge closest to the substrate. The tapered nose on the inner edge reduces the shadowing effect on the edges of the substrate, prevents cracking and arcing of the sub-clamp with the substrate, and reduces the amount of deposition on the gasket.
When introducing elements of the present disclosure or exemplary aspects or embodiments thereof, the articles “a,” “an,” “the” and “said” are intended to mean that there are one or more of the elements.
The terms “comprising,” “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B and object B touches object C, the objects A and C may still be considered coupled to one another—even if objects A and C do not directly physically touch each other. For instance, a first object may be coupled to a second object even though the first object is never directly in physical contact with the second object.
While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
