TW201438137A - Substrate carrier - Google Patents

Abstract

A substrate carrier for plasma processing apparatus is disclosed, comprising: a base plate assembly comprising a platform on which a substrate is placed in use, the volume to be occupied in use by a substrate placed on the platform constituting a substrate zone; and a top plate assembly on the base plate assembly, the top plate assembly comprising a top plate having an aperture therethrough surrounding the substrate zone and one or more retention members extending into the aperture, over a portion of the substrate zone, such that in use a substrate disposed in the substrate zone is retained in a fixed position between the base plate assembly and the top plate assembly. The upper surface of the top plate, facing away from the base plate assembly, is substantially planar and the one or more retention members protrude above the substantially planar upper surface of the top plate.

Description

Substrate carrier

The present invention relates to a substrate carrier for use in a plasma processing apparatus and the like, particularly a "sandwich" type substrate carrier. The invention also discloses a method for manufacturing a substrate carrier and a method for mounting a substrate.

The high throughput requirements for plasma processing, combined with commercially achievable substrate sizes, result in high etch and deposition rates (very high etching or deposition rates during single wafer processing or dielectric etching or The need for deposition rates for batch processing). This high rate process tends to heat the substrate (or "wafer") so it must be cooled to maintain the desired process temperature. This cooling is achieved by facilitating heat transfer between the substrate and the surface on which it is used to support the substrate, such as a wafer stage, during processing. Typically this is achieved by supplying a heat transfer fluid, such as helium, to the back side of the substrate, which has the effect of increasing the pressure behind the substrate. The pressure generated is typically in the range of 5 to 26 mbar.

In the case where the pressure in the processing chamber is less than the pressure behind the substrate, the substrate must be fixed to position to prevent the pressure differential from blowing the wafer away from the support surface. Many techniques for securing substrates have been disclosed and are generally divided into two categories. The first category is an electrostatic chuck (usually formed integrally with the substrate stage of the processing chamber), which is recognized as a technique for holding a single conductor, semiconductor or metal coated substrate. Surgery. Here, the clamping is achieved by electrostatic attraction between the substrate and the carrier. Some examples of electrostatic chucks are found in U.S. Patent No. 6,344,105 and US-A-2003/0219986. However, since a very high voltage must generally be applied in order to obtain a sufficient clamping force, the electrostatic chuck is a relatively complicated and expensive device and is also less suitable for fixing a dielectric substrate such as sapphire. Electrostatic chucks for holding a plurality of substrates in a batch have been proposed (for example, see WO-A-2007/043528), but the risk of failure of any one or more wafer holding positions will cause the system to have a high Cost is not attractive.

An alternative method is to mechanically secure the substrate, which is typically achieved by holding the substrate between the lower and upper components, so the resulting assembly is often referred to as a "sandwich" carrier. This configuration can be used for substrates of any material and can be configured for single wafer processing or for carrying multiple substrates simultaneously. Sandwich-type carriers also have the advantage that substrates of different sizes can be directly accommodated in the processing chamber, simply selecting the appropriate carrier (or simply changing its top plate depending on the design of the carrier) without the need for formation Any changes are made to the hardware of the portion of the processing chamber itself (e.g., wafer table or platform holder).

Typical types of sandwich-type carriers well known in the art are depicted in Figures 1 and 2. 1a and 1b each show a plan view and a cross-sectional view of a sandwich-type carrier that is clamped to an electrode or wafer stage 7 in a plasma processing chamber (not shown) via a clamping ring 5. A plurality of substrates 4 are placed between the top plate 1 and the bottom plate 2. The top plate 1 has apertures 10, each of which exposes a substrate 4 to the processing chamber, and the protrusions 11 of the top plate extend over portions of the substrate to hold it in place. The bottom plate 2 has a passage 2a therethrough to transfer heat transfer fluid to the back surface of each substrate 4, and a seal 3 (such as an O-ring) is adjacent to each substrate to reduce Less or prevent fluid from leaking into the processing chamber. A seal 6 is also provided between the bottom side of the bottom plate 2 and the wafer stage 7. Due to the bolted connection (not shown) between the top plate 1 and the bottom plate 2 and/or depending on the clamping force applied to the carrier via the clamping ring 5 when in the process chamber, the substrate 4 becomes completely fixed.

The need to extend one or more protrusions of the top plate beyond each substrate inherently reduces the available surface area of each substrate. However, this problem is aggravated by the formation of the exclusion regions around the periphery of the substrate in which the process conditions are not uniform. As shown in Fig. 2 for the carrier of Fig. 1, it is assumed that the standard conditions (high density plasma, high DC bias, and low pressure) are generally used for plasma etching of sapphire wafers. The presence of the top plate 1 adjacent the substrate affects the geometry of the plasma sheath 8 formed over the substrate. As shown in Fig. 2a, which is shown in Fig. 1a along the cross section of line Y-Y', adjacent to the edge of the aperture 10 in the top plate 1, the sheath 8 is subjected to local deformation. The foregoing phenomenon results in a decrease in ion density in the region labeled 8a, and an increased ion density reaches the surface (8b) of the top plate. The region 8a where the ion density is reduced includes the edge region E of the substrate 4. In addition, jacket deformation can promote ion impact from a desired direction (perpendicular to the top surface of the substrate). Therefore, the features etched in this region E will be tilted. Since in practice, features etched or deposited in this region E will generally not be available, region E is referred to as the exclusion region. Some examples of the prior art are disclosed in US-A-4,400,235, US-A-542,140, US-A-6,123, 804, US-A-5, 660, 673, and US-A-2010/0162957.

Figure 2a of the above discussion shows the exclusion zone E between the projections 11, wherein the top plate 1 itself does not extend over the substrate 4. The exclusion zone E extends further to the interior of the substrate at the location of the projection 11, as shown in Figure 2b, which is a cross-section along line Z-Z' in Figure 1a.

In a typical sandwich-type carrier configuration, even in the space between the protrusions 11, the exclusion region E can extend a few millimeters on the substrate 4, which accounts for a significant proportion of the total substrate area. For example, the exclusion zone is usually 3 mm or more. In order to increase the usable surface area of the substrate (and thus finally obtain a good device), it is desirable to be able to appropriately reduce the exclusion area.

The present invention provides a substrate carrier for a plasma processing apparatus, the substrate carrier comprising: a substrate assembly including a platform on which the substrate can be placed in use, and, in use, a substrate disposed on the platform The occupied volume constitutes a substrate region; and a top plate assembly on the bottom plate assembly, the top plate assembly including a top plate and one or more retaining members having apertures therethrough and surrounding the substrate region, the one or more The retaining members extend into the apertures and are positioned on a portion of the substrate region such that, in use, the substrate disposed in the substrate region is held in a fixed position between the backplane assembly and the top panel assembly.

Wherein, the upper surface of the top plate facing away from the bottom plate assembly is substantially planar, and one or more retaining members project above the upper surface of the substantially planar top plate.

By arranging the one or more retaining members to protrude on the upper surface of the substantially planar top plate (in other words, reducing the height of the upper surface of the top plate relative to the retaining member), it substantially reduces the extent of sheath deformation. In particular, only the holding member itself needs to protrude above the height of the wafer surface, and the present invention can reduce the height around the surrounding portion of the top plate. Therefore, the spacing between the holding members can be The size of the exclusion zone is significantly reduced or completely eliminated, thereby increasing the usable surface area of the substrate. Preferably, a plurality of retaining members spaced apart from one another are provided around the aperture. In the space between the holding members, nothing extends over the substrate, so that it is completely exposed to the reaction chamber here. Any number of retaining members can be provided, more preferably at least three. Advantageously, the retaining members are equally spaced around the aperture. The retaining member is configured to abut against and apply pressure to the upper surface of the substrate to retain it in position.

Any degree of reduction in height difference between the upper surface of the top plate and the surface of the substrate (relative to the difference in height between the top of the holding member and the surface of the substrate) will reduce the exclusion area. In some cases, there may be a non-zero optimal height difference. However, in a particularly preferred embodiment, the top surface of the substrate is at the same height as the top surface of the carrier when in use. For example, the inventors of the present invention have discovered that very good results can be produced in a typical sapphire etching process. Therefore, preferably, the upper surface of the top plate is substantially coplanar with the upper surface of the substrate region. Any feature that protrudes at the level of the substrate surface (such as the retaining member) can interfere with the plasma sheath, and therefore, the number and size of this feature should preferably be kept to a minimum. By locating the upper surface of the top plate to the same height as the upper surface of the substrate, the geometry of the plasma sheath is essentially undisturbed, resulting in a substantially uniform processing condition over a larger proportion of the substrate. .

In terms of "essentially coplanar", it is preferred that the upper surface of the top plate and the upper surface of the substrate region are coplanar in the range of plus or minus 1 mm, more preferably plus or minus 0.75 mm, and more preferably plus or minus 0.5 mm. . Similarly, preferably the top surface of the top plate is parallel to the upper surface of the substrate region (and/or thus parallel to the platform, which will generally define the orientation of the substrate).

In a preferred embodiment, the upper surface of the top plate is substantially coplanar with the upper surface of the substrate, and the bottom side of the holding member (which contacts the substrate during use) is essentially the same height as the upper surface of the top plate in use. . Again, "intrinsic height" herein preferably means within plus or minus 1 millimeter, advantageously plus or minus 0.75 millimeters, and more preferably plus or minus 0.5 millimeters.

A typical substrate has a thickness ranging between 0.5 and 2 millimeters, more typically between 0.4 and 1.5 millimeters, and advantageously when the top surface of the top plate is within the thickness of one substrate, and more preferably Within the thickness of the substrate above or below one half of the upper surface of the substrate, and optimally the same height as mentioned above. Therefore, depending on the substrate at the time of use, the upper surface of the top plate is preferably at a height of between 0 and 4 mm from the upper surface of the platform, more preferably between 0.25 and 3 mm, and more preferably It is between 0.4 and 2 mm and is optimally between 0.4 and 1.5 mm.

The plasma jacket may also be deformed by a depression in the height of the upper surface of the substrate/top plate, which is formed, for example, by any gap between the top plate and the substrate. Accordingly, it is preferred that the pore size be selected such that any lateral gap between the top plate and the substrate region is 2 mm or less, more preferably 1 mm or less. In this way, the sheath deformation can be further reduced as with the resulting exclusion zone.

The top plate assembly can be implemented in a variety of different ways. In one embodiment, the retaining members are integral parts of the top panel and are fixed relative to each other. For example, the top panel can be modularized or machined to incorporate both the retaining member and the top surface of the recess as described above.

However, in certain preferred embodiments, the top plate and the retaining members are flexibly coupled relative to each other. Since only the holding member is coupled by flexibility While indirectly applying a clamping force from the top plate to contact the substrate, this can reduce the risk of damage to the substrate during loading or unloading of the carrier. Since the top plate may generally be subjected to a clamping force that varies between its entire area, the top plate may be subject to local deformation, and if the local deformation is transferred to the substrate, the risk of breakage may increase due to stress concentration. Likewise, if the clamping structure is in contact with the substrate point or line during loading or unloading of the carrier (unlike planar contact), the risk may increase due to deformation of the top plate and damage may occur. The clamping force applied to the substrate by the top plate is partially relieved by providing a flexible coupling between the top plate and the holding members that contact the substrate during use, as the top plate is absorbed or altered relative to the movement or deformation of the substrate (eg, This risk can be greatly reduced by varying the strength and/or direction of the flexible coupling prior to delivery to the substrate.

Further preferably, the carrier is configured to hold a plurality of substrates (discussed further below), and the respective retaining members of each of the substrates can also be moved independently of the retaining members for the other substrates relative to the top plate. In this way, finally, considering the inconsistency in the pressure applied by the top plate, the force applied to each substrate can be changed by a flexible connection. Still further, each of the retention members can be independently mounted such that even those members configured to hold the same substrate can provide independent adjustment.

The type of the above-described flexible coupling can be achieved in several ways. In some preferred embodiments, the retaining member is carried on the top plate via the resilient connector. This reduces the total number of parts and allows for faster assembly since the top plate and the retaining member can be positioned in one action. However, especially when the carrier is designed to hold a plurality of substrates (for batch processing), the risk of damage may occur due to misalignment of any substrate, so placement in the top plate assembly It is necessary to position the substrate on the corresponding platform with high accuracy.

Thus, in a particular preferred embodiment, the retaining member is carried by a retaining body spaced from the top panel, the retaining member preferably forming an integral portion of the retaining body. The retention body can then be positioned to align the substrate prior to providing the top plate to hold the retention body in place. The flexible coupling between the top plate and the retaining member may take the form of a flexible interconnect assembly (e.g., a spring) between the top plate and the retaining body, but is more preferably incorporated into the retaining body itself.

Accordingly, in a preferred embodiment, the top plate is configured to contact the retaining body at one or more contact portions of the retaining body that resiliently couple the retaining members such that advancement of the top plate toward the base plate assembly results in flexibility of the resilient connector member Deformation. For example, the contact portion may be provided on the spring beam portion of the retaining body that will undergo elastic deformation relative to the retaining member after contacting the top plate.

The retaining body can comprise a single retaining member, but the retaining body advantageously carries a plurality of spaced apart retaining members, and the retaining members are preferably equally spaced from one another. For example, the retaining body can have four retaining members that are 90 degrees apart from one another, six retaining members that are 60 degrees apart from one another, or any other number. Generally, the larger the substrate, the more holding members are needed to secure it. If the substrate has a particular area that is preferably used for contact, the position of the retaining member can be designed for this purpose.

Where the retaining body comprises a plurality of retaining members, each retaining member preferably has an elastic connecting member having one or more contact portions that are substantially independent of the resilient connection for the other retaining members. Pieces. In this way, if force is applied to the contact portion by the spatially varying top plate, the force will be transmitted to the holding member to various degrees by various elastic connecting members, thereby reducing the influence of the difference and the substrate. The stress concentration on the top is minimized.

In some advantageous embodiments, the retaining body includes a flange disposed between the top plate and the bottom plate assembly such that, in use, the flange is advanced by the top plate toward the bottom plate assembly (or similarly, by the bottom plate assembly Against the top plate), there is an elastic connection between the flange and the retaining member. Here, the flange provides one or more of the contact portions discussed above. In a first preferred embodiment, the resilient connector includes a joint between the flange and the retaining body, the flange being biased toward the top plate such that compression of the top plate against the base plate causes a flange around the joint Elastic deformation. It will be appreciated that the flange may be an integral part of the retaining body having a joint formed by defining a fold line in the material of the retaining body of the flange. In another preferred embodiment, the resilient connector includes an extension spring extending between the flange and the retaining member, the extension spring preferably forming an integral portion of the retaining body. The top panel can include a recess or protrusion disposed beneath the surface thereof that is configured to receive the retaining body and/or the contact retaining body at selected locations.

The retaining body can take any shape but preferably the retaining body is shaped to substantially conform to the perimeter of the substrate region. That is, in the case of a circular substrate, the retaining body preferably has a circular cross section (as discussed below), and in the case of a square or rectangular substrate, the retaining body cross section will likewise be square or rectangular. The most typical substrate is circular in nature (although it can be provided, for example, as a flat edge), and thus in a preferred embodiment, the retention body is essentially cylindrical or frustoconical (and therefore has a circular cross section), one Or the plurality of retaining members extend inwardly toward the interior of the cylinder or frustum, and any flange, if provided, extends outwardly from the interior of the cylinder or frustum. By arranging the retention body to be the same shape as the substrate, placing the retention body on the substrate prior to clamping with the top plate helps center the substrate in its proper position.

In the case of a lateral gap between the top plate and the substrate region, in a preferred embodiment, the gap is at least partially filled by the retaining body. Therefore, in the space between the holding members, it is preferable to keep the upper surface of the body substantially the same height as the upper surface of the top plate. This helps the processing chamber to exhibit an essentially flat surface, and thus the deformation of the plasma sheath can be further reduced.

Preferably, the resilient connector between the contact point and the retaining member also has the same symmetry as the substrate region, preferably rotational symmetry. Since the force generated by the deformation of the elastic connecting member is transmitted to the substrate via the holding member, the force component that is not perpendicular to the surface of the substrate will be offset by the symmetry of the spring disposed in the holding body. Thereby the possibility of holding the member sliding on the substrate during installation and the possible damage can be greatly reduced.

Since the retaining member must extend over the substrate to secure it, it is not possible to completely eliminate the exclusion zone adjacent to each retaining member. Preferably, however, the or each holding member has a maximum height of 3 mm or less, and more preferably 2 mm or less, in a direction parallel to a normal to the substrate region. In this way, the extent of the exclusion zone surrounding the retaining member can be minimized.

The lateral extent of the retaining member is also preferably maintained at a minimum required to secure the substrate to the proper location. Preferably, the or each retaining member extends over the substrate area by a distance of 3 mm or less from the top plate, preferably 2 mm or less. In a particularly preferred embodiment, the total area of the substrate area covered by the one or more retention members is 2% or less of the total area of the substrate area, and preferably 0.5% or less.

The bottom plate may consist solely of a platform having a top plate assembly that is mounted around the platform or mounted on the top of the platform. However, in a better example, The platform forms a defined area of the portion of the bottom plate that extends below the top plate outside the platform region. The platform may be of the same height as the rest of the base plate, but in certain preferred embodiments, the platform protrudes relative to the floor adjacent thereto and preferably extends into the apertures provided in the top plate. This configuration allows for the use of a thicker top plate that is stronger and capable of applying a larger and more consistent clamping force, while still maintaining its upper surface substantially the same height as the substrate, for the reasons discussed above.

Advantageously, the platform essentially has the same lateral shape as the substrate area. Where the retaining member is carried on the retaining body, the platform is preferably surrounded by one or more recesses in the bottom plate for receiving the retaining body. This also helps to properly position and position the retaining body on the bottom plate during assembly of the carrier, which ultimately improves the alignment of the substrate.

As discussed above, during processing, the etching and deposition processes tend to heat the substrate, so there is a strong need to be able to remove thermal energy from the wafer in a spatially consistent manner to maintain consistent processing conditions. Thus, in a particularly preferred embodiment, the platform has one or more passages therethrough to allow transfer of a heat transfer fluid, such as helium, to the bottom side of the substrate disposed in the substrate region during use. Or removing the heat transfer fluid from the bottom side of the substrate. This significantly reduces the thermal impedance between the substrate and the underlying wafer table (typically the controlled temperature).

Similarly, where the bottom plate assembly extends below the top plate assembly on the outside of the platform, it is preferred to provide one or more passages therethrough between the outside of the platform to allow transfer of heat transfer fluid to the bottom side of the top plate assembly. And/or removing the heat transfer fluid from the bottom side of the top plate assembly. This is to improve the heat transfer between the top plate and the bottom plate assembly.

The substrate can be placed flat on the platform during processing, i.e., supported by the platform over its entire surface. However, this can lead to heat transfer behind the wafer Non-uniform dispersion of fluid. Thus, in some preferred embodiments, the platform further includes a (preferably continuous) raised end edge disposed about the periphery of the platform, whereby in use, the substrate disposed on the raised end edge is on the substrate The volume for supplying the heat transfer fluid is defined between the bottom side and the platform. By providing this type of limited space between the substrate and the platform, the consistency of the pressure of the heat transfer fluid can be increased and thus its own heat transfer can be enhanced.

The heat transfer fluid can flow out to bind other gases in the processing chamber, and thus in many embodiments, no sealing elements are provided behind the substrate. The omission of the seal provides several attendant advantages, which will be discussed further below, which may result in reduced risk of damage during loading and unloading and permitting the use of a thinner top plate.

However, in other embodiments, it is preferred to reduce leakage of the heat transfer fluid into the chamber, and thus the base plate assembly further includes an elastomeric seal disposed in a recess extending around the periphery of the platform, whereby, in use, The substrate disposed on the seal defines a sealed volume for supplying the heat transfer fluid between the bottom side of the substrate and the platform. This provides a further advantage in that, in the absence of a fluid that is significantly out of the back region of the wafer, the pressure of the fluid will become substantially uniform throughout the area defined between the substrate, the seal and the surface of the platform. Therefore, the consistency of heat transfer in this region is primarily determined by the actual gap between the substrate and the platform.

Regardless of whether the seal is disposed between the platform and the substrate, the base plate assembly preferably further includes an elastomeric seal disposed beneath the surface of the base plate assembly, whereby the base plate assembly is disposed on the substrate table during use A sealed volume for supplying a heat transfer fluid is defined between the bottom side of the base plate assembly and the substrate table.

In a preferred embodiment, the elastomeric seal comprises an O-ring and may be made, for example, of rubber. Advantageously, the elastomeric seal has a Shore A hardness of 60 or less. Since such a reasonably soft material can be more easily deformed, it is preferred to have a good seal between the substrate and the platform. In order to achieve a desired seal, a stiffer material (having a higher Shore A value) would require a greater force applied by the top plate, which may be incompatible with the preferred elastomeric coupling described above. In addition, a larger force value requires a thicker and more rigid top plate, which increases the height of the upper surface, which is not appropriate for the reasons discussed above.

Preferably, the main components of the substrate carrier are formed from a material that is effective to conduct thermal energy and charge to pass through the carrier from which the wafer stage of the carrier is mounted to establish the desired thermal and electrical processing conditions. For example, as noted above, during processing, it may be desirable to transfer thermal energy away from the substrate to the (cooled) wafer stage, and conductive materials will help achieve this. Likewise, in many processes, a bias voltage or RF bias is applied to the substrate by the wafer stage, and the conductive carrier is capable of transferring the bias from the platform to the substrate. Accordingly, preferably, the base plate assembly, the top plate assembly and/or the retaining body (if provided) comprise electrical and thermal conductive materials, and are preferably aluminum or aluminum alloy. In another preferred embodiment, when the bottom plate is made of a conductive material and at the same time the top plate is made of an insulating material such as alumina, an RF bias can be preferentially applied to the substrate.

If the substrate carrier is positioned horizontally in the processing chamber, the weight of the top plate assembly can provide sufficient clamping force to secure the substrate for positioning. Preferably, however, a connecting member can be provided to hold the top plate assembly in position against the bottom plate assembly. This can be provided by existing processing chamber hardware, such as a wafer table fixture that can be used to directly clamp the top plate assembly to the wafer table (with the backplane assembly positioned therebetween). Alternative Alternatively or additionally, the substrate carrier may have separate members for joining the bottom plate and the top plate assembly. Thus in a preferred embodiment, the carrier further includes a connector for urging the top plate assembly against the bottom plate assembly. The connector can include, for example, a clamping assembly or bolt assembly that is configured to push the top plate assembly against the bottom plate assembly.

As previously mentioned, the substrate carrier can be configured to hold one or more substrates. In the case where the carrier is used to carry a plurality of substrates, the bottom plate assembly preferably includes a plurality of platforms, each of which is used to support one substrate when in use, each platform defining a respective substrate region, and the top plate has a plurality of substrates Positioned to the apertures corresponding to the respective substrate regions, at least one retention member extends from the top plate assembly to each of the apertures over a portion of each of the respective substrate regions.

As previously mentioned, the retaining members may be formed integrally with the top plate, or preferably elastically coupled, but more preferably, the retaining members extending into each of the apertures are carried on the respective retaining bodies for each of the pore systems Provide a holding body. Because each substrate is placed on its respective platform, it is advantageous to have the retention body mounted to properly align the substrate and hold it in place. This step can be repeated individually for each substrate before being applied to the top plate.

The platform can be provided as a separate component, each platform being mounted to the top plate or, for example, on a wafer table. Preferably, however, the plurality of platforms form part of the base plate that connects the platform. Forming the platform as an integral unit can reduce the number of parts and simplify assembly of the carrier.

The present invention further provides a substrate carrier assembly comprising a substrate carrier as described above and at least one substrate disposed and defining a substrate region. Therefore, the upper surface of the substrate corresponds to the upper surface of the substrate region described above. The carrier can be used for any type of substrate, but advantageously at least one of the substrates is a dielectric substrate and The best is a sapphire substrate.

The present invention also provides a plasma processing apparatus comprising a substrate carrier or substrate carrier assembly, each as described above. The plasma processing apparatus can be, for example, a plasma etching tool or a plasma deposition chamber. The apparatus can, for example, be configured to perform plasma etching to produce a patterned sapphire substrate (PSS), which is typically used to produce high brightness light emitting diodes (LEDs).

Typically the plasma processing apparatus will further comprise a substrate stage on which the substrate carrier can be placed; and a platform connector, preferably a clamping arrangement or a bolt arrangement for pushing the substrate carrier against the substrate stage.

The present invention further provides a method of fabricating a substrate carrier for a plasma processing apparatus, the method comprising: selecting a size of a substrate to be carried by the substrate carrier; providing a substrate assembly comprising: being configured to be used at the time of use a platform on which the selected size substrate is placed, the volume occupied by the substrate disposed on the platform is used to form the substrate area of the selected size; and the top plate assembly is provided on the bottom plate assembly, the top plate The assembly includes a top plate having voids therethrough and surrounding the substrate region, and one or more retention members extending into the apertures on a portion of the substrate region such that, in use, the substrate disposed in the substrate region is retained in the substrate The fixed position between the assembly and the top plate assembly.

Wherein, the upper surface of the top plate facing away from the bottom plate assembly is substantially planar and the one or more retaining members protrude from the upper surface of the substantially planar top plate.

As described above, by arranging the upper surface of the top plate to be placed below The height of the upper surface of the member reduces the distortion of the plasma jacket and reduces the size of any exclusion zone. Again and preferably, a plurality of retaining members spaced apart from one another may be provided around the aperture, and more preferably at least three are provided. The retaining members are configured to abut against and apply pressure to the upper surface of the substrate to hold it in place during use.

As previously mentioned, the top surface of the top plate is preferably substantially coplanar with the upper surface of the substrate region, the position of which will correspond to the position of the upper surface of the substrate selected once positioned on the platform. This can be determined by knowing the thickness of the selected substrate. Advantageously, the upper surface of the top plate is coplanar with the upper surface of the substrate region in the range of plus or minus 1 mm, preferably plus or minus 0.75 mm, more preferably plus or minus 0.5 mm. Likewise, the bottom side of the retaining member, which in contact with the substrate during use, is preferably substantially the same height within plus or minus 1 mm of the top surface of the top plate in use, advantageously plus or minus 0.75 mm, more preferably Positive and negative 0.5 mm. Preferably, the upper surface of the top plate is parallel to the upper surface of the substrate region. Advantageously, the size of the apertures is selected such that any gap between the top and substrate regions is 2 millimeters or less.

The present invention also provides a method of mounting a substrate for plasma processing, comprising: placing a substrate on a platform forming a portion of the bottom plate assembly; and placing the top plate assembly on the bottom plate assembly, the top plate assembly including the aperture a one or more holding members extending therethrough and surrounding the top plate of the substrate, and extending to one of the apertures on a portion of the substrate, such that the substrate is held in a fixed position between the bottom plate assembly and the top plate assembly; wherein, the back side is always The upper surface of the top plate is substantially planar and one or more retaining members project from the upper surface of the substantially planar top plate.

The same advantages as described above can be achieved by arranging the retaining members to protrude from the upper surface of the top plate. As previously mentioned, preferably, a plurality of retaining members spaced apart from each other around the aperture are provided, and more preferably at least three retaining members are provided. The retaining members are configured to abut against and apply pressure to the upper surface of the substrate to hold it in place during use.

Again and more preferably, the upper surface of the top plate is substantially coplanar with the upper surface of the substrate (at its mounting position). Advantageously, the upper surface of the top plate is coplanar with the upper surface of the substrate region in the range of plus or minus 1 mm, preferably plus or minus 0.75 mm, more preferably plus or minus 0.5 mm. Likewise, the bottom side of the retaining member (in contact with the substrate in use) is preferably substantially the same height as the upper surface of the top plate in use, in the range of plus or minus 1 mm, advantageously plus or minus 0.75 mm, more preferably Positive and negative 0.5 mm. Preferably, the upper surface of the top plate is parallel to the upper surface of the substrate. Preferably, the size of the apertures is selected such that any gap between the top and substrate regions is 2 millimeters or less.

As discussed previously, the roof assembly can be constructed in a number of ways. In a particularly preferred embodiment, the retaining member is carried by a retaining body separate from the top plate, the retaining member preferably forming an integral portion of the retaining body, and the method includes placing the retaining body on the base plate assembly, The retaining member extends partially over the substrate and the top plate is then placed over the retaining body. This facilitates the loading/unloading procedure and also ensures good alignment of the substrates in the carrier.

Advantageously, the retaining body substantially conforms to the surrounding shape of the substrate such that positioning the retaining body on the substrate can result in centering of the substrate relative to the platform.

In the case where a plurality of substrates are mounted for plasma processing, the method preferably further comprises resetting the top plate assembly before placing the top plate assembly on the bottom plate assembly Each of the plurality of substrates is placed on a respective platform of the backplane assembly. Advantageously, a plurality of corresponding retaining bodies are provided and the retaining body is disposed on the base plate assembly, the retaining members extending partially over each respective substrate prior to placement of the top plate on the plurality of retaining bodies. This further simplifies loading and unloading of the carrier and helps to avoid damage to the substrate.

1, 8b, 21‧‧‧ top board

2‧‧‧floor

3‧‧‧Seal

4‧‧‧Substrate

4a‧‧‧ top surface

5‧‧‧clamp

6‧‧‧Seal

7‧‧‧ Wafer Table

8‧‧‧Plastic sheath

8a, 9a‧‧‧ area

9b‧‧‧ Sealed area

9c‧‧‧External area

10, 21a‧‧‧ pores

11‧‧‧ protrusion

20‧‧‧Substrate carrier assembly

21b‧‧‧ upper surface

22‧‧‧Bottom plate assembly

23‧‧‧ platform

23a‧‧‧ surrounding recess

24‧‧‧Flexible connection

25, 27a‧‧‧ Keeping components

25a‧‧‧Top chamfer

25b‧‧‧Chamfering below

25c‧‧‧ bottom side

26‧‧‧Maintaining the ontology

26a‧‧‧ cylindrical wall

26b‧‧‧Circumference beam

26c‧‧‧Free end

27‧‧‧Flange

27b‧‧‧Location

28‧‧‧channel

29‧‧‧ protruding edge

29a‧‧‧Small planar area

30‧‧‧Elastic seals

Examples of substrate carrier, substrate carrier assembly and corresponding method in accordance with the present invention will now be described with reference to the drawings and to examples of conventional systems in which: FIGS. 1a and 1b depict exemplary substrate carriers, respectively. A plan view and a cross-sectional view of a conventional structure of the assembly; the 2a and 2b drawings pass through the cross-section of the substrate carrier assembly of FIG. 1 along lines Y-Y' and Z-Z', respectively; A portion of a cross section of a substrate carrier assembly in accordance with a first embodiment of the present invention is depicted; FIG. 4 shows an exemplary bottom plate assembly for use in the first embodiment; and FIG. 5 shows an illustration for the first embodiment. 3D, 6B and 6c show three examples of the holding body for the first embodiment; Fig. 7 shows a schematic cross section through the line Q-Q' of Fig. 3; Fig. 8 depicts Partial cross-section of the substrate carrier assembly of the second embodiment of the present invention; FIG. 9 is a partial cross-section through the substrate carrier assembly in accordance with the third embodiment of the present invention; Figure 10 is a partial cross-section through a substrate carrier assembly in accordance with a fourth embodiment of the present invention; Figure 11 is a cross-section taken along line R-R' of Figure 10; A partial cross section of a substrate carrier assembly in accordance with a fifth embodiment of the present invention; and a thirteenth view through a schematic cross section of a substrate carrier assembly in accordance with a sixth embodiment of the present invention; A schematic cross-section of a substrate carrier assembly in accordance with a seventh embodiment of the present invention; FIG. 15 is a diagram depicting experimental results, carried on (i) a conventional carrier and (ii) an embodiment in accordance with the present invention The inconsistencies in the features etched in the substrate in the carrier are measured at different distances from the edge of the substrate; and Figure 16 is provided in the substrate (a) using a conventional substrate carrier at (i) distance 1 mm at the edge of the substrate and (ii) 3 mm from the edge of the substrate; and (b) an exemplary SEM image of the features etched at the same distance from the edge of the substrate using a substrate carrier in accordance with an example of the present invention.

For ease of reference, embodiments of the invention discussed below will be primarily described by way of example with reference to a substrate carrier assembly that includes a substrate carrier and at least one substrate loaded into the substrate carrier (or "crystal Circle"), as depicted in Figure 3. It will be appreciated that the substrate carrier itself is typically provided in an unloaded form and that one or more substrates are mounted in the carrier prior to processing. In the case of an idling substrate carrier, the volume that the substrate itself will occupy once it is mounted is the "substrate area" and has the same dimensions as the substrate to be loaded. because Thus, in the drawings, the item labeled "4" while being identified as a substrate hereinafter may alternatively be considered to represent the area of the substrate in the idling substrate carrier.

3 shows a first embodiment of a substrate carrier assembly 20 in which a substrate 4 is held between a bottom plate assembly 22 and a top plate assembly including at least a top plate 21 and a retaining member 25. In this example, the substrate carrier is designed to carry a plurality of substrates 4 for batch processing. The portion adjacent to the substrate 4 is only visible in Figure 3. In fact, the substrate carrier can be used to hold any number of substrates, including a single substrate, the mechanism through which each substrate is to be held is essentially the same. Thus, the components of the substrate carrier will be discussed with reference to a single substrate, although it will be appreciated that the same description can be applied to provide any additional locations on the device for carrying the substrate.

The substrate 4 is positioned on the platform 23 of the bottom plate 22, which preferably projects relative to the surrounding portion of the bottom plate. The platform 23 essentially has the same size and shape as the substrate 4 to be carried, and the substrate is typically circular or nearly circular. One or more channels 28 pass through the platform 23 to enable a heat transfer fluid, such as helium, to pass to the back side of the wafer 4, as will be discussed further below.

The wafer 4 is held on the platform 23 by the holding member 25, and each of the holding members 25 extends a short distance around the wafer 4. The bottom side 25c of each holding member 25 contacts the substrate 4 such that each holding member 25 exerts a downward force on the substrate 4, which force is preferably substantially perpendicular to the surface of the substrate to hold the substrate 4 in place. position. Any number (one or more) of retaining members 25 may be provided depending on the size of the wafer to be carried, but preferably a plurality of such retaining members are provided that are separated from each other by a gap (pitch) around the aperture Open, where the substrate is not covered until its edge. Generally, a larger wafer diameter will require more holding members 25. In the case where the carrier is designed to hold a plurality of wafers for batch processing, Preferably, the force applied to each of the substrates by the retaining members is independent of the force applied to the other substrates mounted in the carrier, and means for accomplishing this will be discussed below.

In this example, the retaining member 25 is carried by the retaining body 26, which will be discussed further below. The holding body 26 is pushed against the bottom plate 22 by the top plate 21 fitted to the holding body 26. The top plate 21 surrounds the substrate 4, which is exposed to the processing chamber environment through the apertures 21a in the top plate 21, which likewise has essentially the same shape as the substrate 4. The height of the upper surface 21b of the top plate 21 (in a direction parallel to the normal to the plate) is lower than the holding member 25, and for assembly on the substrate 4, the holding member 25 protrudes from the surface 21b and thereby holds it at Positioning. As discussed below, the resulting top surface of the substrate carrier facing the processing chamber has little effect on the shape of the plasma jacket, such that the size of any exclusion regions on the edges of the substrate 4 can be reduced.

Therefore, the substrate carrier contains three main components, as shown in the exploded views of Figures 4, 5 and 6. Fig. 4 is a perspective view of the bottom plate assembly 22 used in the first embodiment, and all five wafer processing positions on the carrier are visible in Fig. 4. Each location is defined by a platform 23 on which the wafer 4 will be placed in use. In this example, as clearly shown in Figure 3, each platform is convex relative to its surroundings, however this is not necessary. Moreover, in this example, each platform 23 is defined by a surrounding recess 23a for positioning and positioning the retaining body 26; however, this may also be the case. Each platform 23 of the size and shape desired based carrier preferably by the substrate 4 is determined, and thus the diameter D _P of each platform generally on the nature of the same or slightly larger than 23 (e.g., up to 4 mm) of the substrate The diameter of 4. It will be appreciated that each platform 23 can be sized differently to accommodate different sizes of the substrate.

The bottom plate assembly 22 is typically formed from a thermally and electrically conductive material such as a metal or metal alloy, and preferably an aluminum alloy. The use of this material can promote good thermal conduction away from the substrate 4 and good electrical conduction from any bias applied to the substrate 4 during processing.

In this example, a unitary base plate 22 is used to carry a plurality of substrates. However, in other cases, batch processing may be accomplished with a backplane assembly 22 comprising a plurality of disparate platform units, wherein, for example, the plurality of completely different platform units may be individually mounted directly to the wafer station.

The top plate 21 is a perspective view depicted in Figure 5. Here, the top plate 21 comprises an essentially flat plate having apertures 21a corresponding to each of the platforms 23. Similarly, although in practice the size of each aperture will have to include a minimum clearance (e.g., 1 to 2 mm) between the substrate 4 and the edge of the aperture, the size and shape of the aperture 21a is preferably based on the desired bearing. The substrate 4 and the retention body 26 (as discussed below) are determined. Therefore, the diameter D _{A of} each of the apertures is typically slightly larger than the diameter of the substrate 4 (and the platform 23). The top plate 21 is also preferably made of a thermally and electrically conductive material such as an aluminum alloy.

The retaining body 26 can carry the retaining member 25 in a number of different forms. In one example, the retaining body 26 may comprise only a solid cylinder (or a truncated cone having a slope of less than 10 degrees) having a flange 27 facing outwardly as its lower end and a retaining member facing inwardly 25 is placed around its upper end. The top plate 21 is placed on the holding body 26 as shown in Fig. 3 to bring the top plate 21 into contact with the flange 27, thereby holding the holding body 26 in position and thus fixing the substrate 4.

It is preferable to use the holding body 26 separated from the top plate 21 in this manner. Because it enhances the convenience of loading and unloading the carrier. In particular, in order to load the carrier, the first substrate 4 can be placed on one of the platforms 23 depicted in FIG. The retaining body 26 can then be placed on the base plate 4, maintaining the cylindrical (or frustoconical) shape of the body 26 such that it can be easily positioned and placed in the recess 23a around the platform 23. If necessary, this procedure will cause the substrate 4 on the platform to be self-centered. Therefore, when the top plate 21 is then placed on the bottom plate 22, it ensures that no collision occurs between the top plate 21 and any one or more of the loaded substrates 4. In addition, each of the substrates is held in position by its corresponding holding body 26, and at the same time the remaining substrates can be loaded. Overall, the risk of substrate damage is reduced and the loading speed is increased.

Therefore, the retaining body 26 acts only to individually position and temporarily hold the members of each of the substrates before applying the top plate 21. However, in a more preferred embodiment, a flexible coupling is provided between the retaining member 25 and the top plate 21, and advantageously, the flexible coupling can be achieved by retaining the design of the body 26. By providing a flexible coupling between the top plate 21 and the retaining member 25, pressure is not directly applied to the substrate 4 by the top plate 21, but only indirectly and in a modified manner via the flexible connecting member. Apply. Therefore, any impact force applied to the carrier from the top plate 21 will be partially absorbed without being transmitted to the substrate, and any further stress concentration due to deformation in the top plate 21 will be dissipated to some extent. Again, each retention body 26 will function independently of the retention body disposed in the carrier for other substrates.

Figures 6a, 6b and 6c show three examples of retaining bodies 26 that form a flexible coupling between the top plate 21 and the retaining members 25 in conjunction with the resilient members. The retaining body 26 shown in Figure 6a comprises an essentially cylindrical body as previously described, It has a flange 27 extending outwardly at the base of the cylinder and a retaining member 25 extending radially inwardly at the tip end of the cylinder. The flange 27 is connected to the wall of the cylinder only at spaced intervals corresponding to each of the retaining members 27a. The flanges 27 are separated between the joint points 27a such that two free ends are formed at each of the marks 27b. These portions of the flange can thus act as spring beams that can flex in a vertical direction in the vicinity of the point of attachment to the remainder of the retaining body. When assembled, as shown in Fig. 3, the top plate 21 rests on the flange 27. In particular, the top plate 21 rests on the flange 27 in its free end region around the position 27b. The foregoing configuration can be achieved by either applying a pre-stress to the free end of the flange 27 and/or by providing any contact point on the bottom side of the downwardly projecting top plate 21. Therefore, when the top plate 21 is placed on the holding body 26 and is advanced toward the bottom plate assembly 22, the flange 27 will undergo elastic deformation, and finally the force applied to the substrate 4 via the holding member 25 is substantially uniform without Local stress concentration.

In the example of Fig. 6a, the spring function of the retaining body can be effectively achieved by embedding a simply supported beam in the flange 27 (i.e., the free end 27b of the flange constitutes a beam). In other examples, more complex configurations of the beam can be formed in the cylindrical wall of the retaining body, and examples of this method are depicted in Figure 6b. Here, the retaining body 26' has the same overall shape as previously described, i.e. has a generally cylindrical shape with a flange 27 at its outwardly extending base and a retaining member at its distal end extending inwardly. 25. The cylindrical wall 26a of the retaining body 26' is formed by a network of beams which together constitute a spring that can be stretched and/or compressed in the axial direction of the cylinder. Therefore, the pressure applied to the flange 27 by the top plate 21 will be changed by the embedded spring before being transferred to the substrate 4 by the holding member 25.

In each of the above examples, the retention body 26 includes a radially outward extension The flange 27 is extended to engage the top plate 21. However, this is not essential, and more generally, it is desirable that the top plate 21 contact the retaining body in one or more contact locations that are resiliently coupled to the retaining member 25. In a further example illustrated in Figure 6c, the retaining body 26'' is also substantially cylindrical in shape with a retaining member 25 extending radially inwardly at its top edge. However, in this example, no flange is provided, and instead the top plate 21 is configured to rest on the top edge of the cylindrical wall of the retaining body 26 at a location remote from the retaining member 25. The cylindrical wall is formed by a set of circumferential beams, and its free end 26c is unaffected by deflection in the vertical direction. Once assembled, the top plate 21 rests on the retaining member 26'' in the region of the free end 26c. The foregoing configuration can be achieved by applying a pre-stress in the upward direction to the beam 26b and/or providing a contact position that projects downwardly on the bottom side of the top plate 21 in a suitable corresponding position.

Either way, the flexible mechanical coupling between the retaining member 25 and the top plate 21 enables relative vertical movement between the retaining member 25 and the substrate 4 to be reduced or substantially eliminated during loading/unloading of the carrier and throughout processing. . Therefore, since the risk of point or line contact between the substrate and the carrier is lowered, it is possible to avoid introducing the concentrated stress region to the substrate surface, so that the lower surface of the holding member 25 can be kept parallel to the substrate surface at any time.

Further preferably, the beam or other type of flexible connector between the top plate 21 and the retaining member 25 has the same symmetry as the designated substrate 4. For example, in the context of the present invention, the apparatus is designed to carry a circular or nearly circular substrate, and each spring configuration depicted in Figures 6a, 6b, and 6c conforms to a circular configuration. Therefore, due to the spring symmetry disposed in the retaining body 26, any force components applied that are not perpendicular to the surface of the substrate will cancel each other out, It significantly reduces the possibility of the retaining member sliding over the substrate 4.

Therefore, in a preferred embodiment, for example, a separate holding body 26 is attached to each of the substrates 4. Each of the retaining bodies 26 has an elastic connection (such as an embedded beam) that transfers the clamping force provided by the top plate 21 to the retaining member 25. By using the retaining body spaced from the top plate 21, the relative movement of the top and bottom plates 21, 22 does not create stress concentrations such as point or line contact on the substrate 4. The force that holds the substrate against the pressure of the heat transfer fluid on the back side of each substrate is urged toward the top plate 21 toward the bottom plate assembly 22 (eg, via a connecting member such as a screw or bolt, or as The table clamp 5) shown in Fig. 1b is applied, and regardless of the slight distortion of the top plate 21 or the bottom plate 22, each of the holding systems is independently twisted to hold its respective substrate 4.

In each of the above examples, the retaining body (including the retaining member) is preferably formed of a thermally and electrically conductive material such as an aluminum alloy.

As described above, once the top plate 21 is assembled to the bottom plate 22, in all embodiments, the top plate upper surface 21b (facing the interior of the processing chamber) is concave relative to the retaining member 25 projecting therefrom, as in Figure 3 shows. Therefore, the exclusion regions E described above with respect to the 2a and 2b diagrams are reduced or even eliminated in the interval between the holding members 25. The foregoing is illustrated in Fig. 7, which is a cross section along the line Q-Q' in Fig. 3. In the particular preferred embodiment illustrated in Figure 7, the upper surface 21b of the top plate 21 is substantially coplanar with the top surface 4a of the substrate 4 (and thus the bottom side of the retaining member 25) mounted in the carrier. In fact, the upper surface 21b of the top plate 21 is substantially parallel to the top surface 4a of the substrate 4, and any height difference between the upper surface 21b of the top plate 21 and the top surface 4a of the substrate is less than one half of the thickness t of the substrate. In the case, the best results are usually achieved. For example, any height of the two planes The degree difference is preferably 1 mm or less, more preferably 0.75 mm or less. This can be achieved by considering the thickness t of the substrate 4 to be carried and assembling the components such that the height h of the upper surface 21b of the top plate 21 relative to the surface of the platform 23 (when the top plate 21 is fixed in position) essentially corresponds to The thickness t of the substrate is achieved by designing the substrate carrier. Therefore, in a preferred embodiment, since the general substrate has a thickness ranging between 0.5 and 2 mm, and is usually between 0.5 and 1 mm, preferably the top surface 21b of the top plate is at 0.5 from the upper surface of the stage 23. And a height h between 3 mm, preferably between 1.5 and 2 mm, more preferably between 0.5 and 1.5 mm.

As shown in Fig. 7, the result is an approximately planar surface system formed by the combination of the top plate 21 and the substrate 4a (and optionally the holding body 26) in the ideal case away from the holding member 25. Facing the process chamber. Thus, the plasma sheath 8 will be subjected to minimal distortion in the edge regions to achieve substantially consistent processing conditions. In testing, embodiments of the present invention have achieved the technical effect of extending the exclusion zone to less than 1 mm inside the substrate, which is a significant improvement over previous carriers.

In accordance with the same principles, it should be noted that any feature that protrudes from the wafer surface 4a can create an interruption in the plasma jacket 8, and as such, the number and size of features are preferably maintained to a minimum. Preferably, in order to minimize the range of the exclusion regions formed around each of the holding members, the holding member 25 has a maximum height of 3 mm or less in a direction parallel to the normal to the substrate 4, more preferably 2 Mm or smaller. The lateral extent of each of the retaining members 25 is also preferably maintained to be small. For example, each of the holding members 25 may extend over the substrate 4 by 3 mm or less, preferably 2 mm or less. In a particularly preferred embodiment, the total area of the substrate region covered by the one or more retention members is 2% or less of the total area of the substrate 4, preferably It is 0.5% or less.

It will be noted from the drawings that in these examples, each of the holding members 25 projecting on the substrate 4 has a substantially rectangular parallelepiped shape, but preferably has a chamfered edge instead of having a corner of 90 degrees. The upper chamfer 25a (Fig. 6a) is believed to further reduce the deformation of the plasma sheath compared to the complete cuboid shape due to the removal of sharp corners. A chamfer or rounded edge 25b is provided to reduce stress on the substrate during assembly. In use, the bottom side 25c contacts the upper surface of the substrate.

Since the section of the upper surface 21b of the top plate 21 positioned in the space between the holding members 25 serves as an extension of the processing surface of the substrate 4, any lateral gap between the top plate 21 and the substrate 4 may also cause deformation of the sheath. Therefore, it is preferred to maintain any such lateral gap to a minimum. In the first embodiment described above, the apertures 21a formed in the top plate 21 are designed to accommodate the substrate 4 and expose the holding body 26, which makes it easy to assemble because no rotational alignment is required between the holding body and the top plate 21. As shown in the cross section of Fig. 7, due to the gap between the top plate 21, the holding body 26 and the substrate 4, this results in a discontinuous surface adjacent to the periphery of the substrate. Preferably, the region is formed as close to a planar surface as possible by making the upper surface of the holding body approximately the same height as the top surface 21b of the top plate in the space between the holding members 25. It will be appreciated that in order for the aforementioned configuration to be implemented in practice, the example of the retaining body 26 of Figures 6a and c will be modified such that the upper edge of the cylindrical surface reaches the same height relative to the retaining member 25 as in the example of Figure 6b. .

In the second embodiment of the present invention, as in the partial cross section depicted in Fig. 8, the sheath deformation can be further reduced by reducing the size of the aperture 21a' such that the edge of the top plate 21 has a minimum practical clearance. (for example 2 mm or less) directly adjacent to the substrate. In order to achieve this configuration, the top plate 21 is molded to fit over The circumferential surface of the body 26 is held, and a slit 21a'' is provided in the edge of the aperture 21a' to accommodate the holding member 25. Therefore, there is a very small sheath deformation in the space between the holding members 25, and this situation can be considered to be very close to the ideal situation discussed above. In this example, the upper edge of the cylindrical surface of the retaining body 26 will be lowered to accommodate the thickness of the upper plate 22, as shown in the examples in Figures 6a and c. The corresponding edges shown in the example of Figure 6b will be reduced to the same height used in this embodiment.

It should be noted that in the first and second embodiments discussed above, unlike the conventional carrier previously described with respect to Figures 1 and 2, a back seal is not provided behind the substrate 4. However, the inventors of the present invention have found that in many cases, omitting the seal is preferred. While the omission of the seal will cause the heat transfer fluid to flow out to combine with the process gases in the chamber, this is acceptable in many cases and can result in several benefits. First, in order to compress the elastomeric seal 3 and prevent fluid from passing through the seal, the supply of the elastomeric seal to the assembly 3 of conventional carriers such as those of Figures 1 and 2 will generally result in the need to apply a greater force from the top plate. This in turn requires high rigidity and thus the thickness of the top plate. By omitting the seal 3, only a small compressive force is required and the thinner top plate 21 can be used. This helps to reduce the profile of the upper surface 21b of the top plate 21, thereby helping to achieve a smaller amount of plasma sheath deformation as discussed above.

Likewise, the high compressive force required to use the elastomeric seal 3 increases the risk of local deformation of the top plate 21 during clamping of the substrate. This in turn increases the risk of stress concentration during loading or unloading, for example, if the mechanical clamping structure has point or line contact with the substrate, it can cause the substrate to rupture before or after processing. However, this problem can be solved by the top plate 21 and the protection as discussed above with respect to FIG. The holding members 25 are lowered using an elastic connecting member.

Likewise, the desired sealing effect can only be achieved when the substrate 4 is accurately positioned to align with the elastomeric seal 3, which is difficult to achieve in conventional systems. Misalignment may only be detected when the substrate carrier is loaded and processing begins, which is recognized by a sudden increase in heat transfer fluid flow required to reach a set pressure behind the substrate. In this case, using a conventional system, the loaded carrier will need to be removed, unloaded, and restarted. In the system of the present disclosure, this problem can also be alleviated by using the separate holding members 26 for correcting each wafer position as described above before the top plate 21 is introduced.

Another problem that may be encountered during loading or unloading of the carrier is that, in the case of providing an elastomeric seal, when pressed against the substrate, the elastomeric seal fills the recess present in the back of the substrate and is disposed The surface of the recess in the platform carrying the elastomeric seal. When the above problems are encountered during processing in conjunction with temperature changes, there is typically significant adhesion between the seal and the adjacent body, which can cause the substrate to be unloaded and time consuming and pose a risk of substrate damage. By using individual retention bodies, this problem can also be mitigated to the extent that each substrate will be individually unloaded so that the operator can fully notice each substrate as it is manipulated one by one.

In view of the above, in many embodiments, it is preferred not to provide any seal between the substrate 4 and the platform 23. In this case, the substrate 4 can be placed flat against the platform 23. That is, the substrate 4 can be in contact with and supported by the platform throughout the entire area of the substrate 4. However, in order to improve the uniform supply of heat transfer gas behind the substrate 4, it is preferred to provide a small gap between the surface of the platform and the back side of the substrate that allows the heat transfer gas to pass through to all areas of the substrate. In the example of this embodiment as shown in Figure 9, and here the platform 23 includes the entire length around it The extended (continuous) raised end edge 29. In use, the substrate 4 rests on the raised end edge 29 to create a partial seal, and leaves a small planar region 29a between the platform 23 and the substrate 4, which in use is thermally transferred through the passage 28. The fluid is filled. The remaining components of the substrate carrier are essentially identical to the previously described embodiments, although in this example, the retention body 26 carries only three equally spaced retention members 25 rather than six of the previous examples. .

While the disadvantages of using elastomeric seals have been discussed above, in some cases, the benefits of using elastomeric seals are more important than these issues. In particular, the provision of a seal reduces the leakage of heat transfer fluid from the back of the wafer to the process space (which is typically maintained at a vacuum level), thus lacking a significant output of fluid flow, which means thermal transfer behind the wafer. The pressure of the fluid is essentially spatially uniform. Therefore, the consistency of heat transfer in this region is primarily determined by the actual gap size between the associated surfaces of the substrate 4 and the substrate 22, wherein the substrate 4 is disposed on the substrate 22. Consistent thermal transfer is appropriate as this will also improve the consistency of the resulting structure formed during processing.

Thus, FIG. 10 depicts a further embodiment of the present invention in which an elastomeric seal 30 is disposed about the platform 23 behind each substrate 4. The elastomeric seal may, for example, comprise an O-ring, such as a rubber O-ring, and preferably has a Shore A hardness of 60 or less. This is preferred because such suitable soft materials can be more easily deformed resulting in a good seal between the substrate and the platform. In order to achieve the desired seal, a harder material (having a higher Shore A value) would require a greater force to be applied from the top plate, a requirement that may not be compatible with the preferred elastic coupling described above. In addition, a larger force value requires a thicker and more rigid top plate, which raises the height of its upper surface, which is undesirable for the reasons discussed above.

The remaining components of the substrate carrier are identical to the components previously discussed for Figures 3-7. By providing such a seal, the apparatus can be used in processes that are unable to accept a large amount of heat transfer fluid leaking into the process chamber, and the seal can achieve a very low leak rate. As discussed above, the seal also achieves increased consistency of fluid pressure back below most of the substrate surface.

However, an additional problem that may exist with the inclusion of an elastomeric seal is thermal inconsistency in the sealed area. As depicted in Fig. 11, which is along the cross section taken along the line R-R' shown in Fig. 10, an elastic seal 30 is provided on the back surface of the substrate 4 to separate the back of each substrate 4 from the surface. In three areas. The main (central) region 9a of the substrate is in direct contact with the heat transfer fluid at the desired pressure, and thus consistent processing conditions can be achieved. In the case where the seal 30 contacts the substrate 4, the presence of the heat transfer fluid is reduced, and since the elastomeric material has a different heat transfer characteristic than the heat transfer fluid, there will be a temperature difference in the seal region 9b. Outside of the seal 30 in the outer region 9c, there is essentially no heat transfer fluid and the substrate is exposed to the process chamber vacuum environment. Each of the zones 9a, 9b and 9c represents different thermal transfer conditions (and different bias conditions, if the bias is applied via the wafer table), which reduces the uniformity around the adjacent substrate.

To reduce this effect, the elastomeric seal 30 is preferably positioned as close as possible to the edge of the substrate 4 and its lateral width is maintained to a minimum. Also, since the substrate seating surface of the bottom plate 22 has a uniform structure, heat (and bias) inconsistency (except for any back pressure gradient) will not be introduced, so the flexibility can be omitted as in the previous embodiment. Seal 30 is used to avoid this problem. Alternatively, depending on the choice of seal, the adverse effects can be reduced to an acceptable level. For example, the width of the seal is preferably maintained to a minimum and the seal material can be selected to have heat and electricity Conductivity. In another example, different seal cross sections can be used in place of the O-rings. For example, a seal having a triangular cross section can be used to reduce the size of the region 9b: the seal can be configured to press the wafer against one corner of the seal, which can achieve a minimum contact surface area. The foregoing configuration preferably, together with the feature that the seal is positioned near the edge of the wafer and increases the local deformation of the seal, will together provide a good seal with reduced heat inconsistency.

It will be appreciated that elastomeric seals of the type described above can be combined with any of the embodiments disclosed herein. For example, Fig. 12 depicts another embodiment corresponding to that discussed above with respect to Fig. 8, for the reasons described above, the modification is only that it includes an elastomeric seal 30. Although in the embodiments disclosed in Figures 8 and 12, the assembly of the carrier structure will be relatively complicated, as previously described, this is because the retaining member 25 needs to be aligned with the recess 21a, the overall plasma sheath is deformed and associated with the exclusion. The area will be reduced by reducing the gap existing between the top plate 21 and the substrate 4.

As noted above, in order to achieve the benefits of the simplified loading procedure discussed above and to reduce the risk of substrate damage, it is preferred that the top plate 21 and the retaining member 25 are movable relative to one another, more preferably elastically coupled. However, this is not necessary and it is still achievable to reduce the exclusion area without providing these additional benefits.

To illustrate this, Fig. 13 shows an embodiment in which the holding member 25 is integrally formed with the top plate 21. For example, the top plate 21 may be modularized or otherwise formed to incorporate a raised protrusion that extends to and forms the retaining member 25, or the upper surface 21b may be recessed into the retaining member 25 by machining the original flat plate Under height. Implementations such as those depicted in Figure 13 are particularly suitable for single wafer processing other than batch processing to reduce the difficulty of careful alignment with the top plate during substrate loading.

Figure 14 shows a cross section through another embodiment in which the retaining member 25 is carried by the top plate 21 but is resiliently coupled thereto such that the pressure from the top plate 21 is only transferred indirectly to the substrate, thereby preserving some of the above discussed Additional benefits. In this example, the retaining members 25 are carried in slots provided around the apertures 21a and are retained within the slots by extension springs 24. Therefore, the clamping force applied by the top plate 21 can be more uniformly dispersed by the elastic connecting member 24 between the top plate 21 and the holding member 25. The retaining members 25 can be joined, for example, to form a portion of the retaining body 26, as discussed above, or can be separated from one another so that they can move completely independently of each other.

In the two embodiments described for Figures 13 and 14, the top surface 21b of the top plate 21 is also substantially coplanar with the top surface of the substrate 4. Therefore, the bottom side 25c of the holding member 25 is also substantially coplanar with the upper surface 21b of the top plate 21. Therefore, by reducing the height of the upper surface of the top plate relative to the holding member, it is possible to reduce the deformation of the plasma sheath and thereby reduce the exclusion area. To illustrate this result, Figure 15 shows experimental data in which plasma etching options in the edge regions of a 100 mm diameter sapphire substrate can be measured after two very similar low pressure chlorination chemical processing conditions in an ICP plasma processing tool. Degree inconsistency. "Selectivity" refers to the ratio of sapphire etch rate to photoresist etch rate (ie [sapphire etch rate (nm/min)] / [resist etch rate (nm/min)]). The degree of inconsistency measurement in Figure 15 is based on a test point positioned at a distance of between 1 mm and 5 mm from the edge of the sapphire wafer, plus a point in the center of the wafer. The degree of selectivity inconsistency for each of the given positions along the x-axis in the figure is determined by the selectivity ratio compared to each test point, which falls at a specified distance from the edge of the wafer. On or within. Therefore, at 1 mm from the edge of the wafer, the inconsistency values are based on The diameter is calculated up to the etched depth of the sapphire and photoresist measured at 1 mm from the edge of the wafer, and at 3 mm from the edge of the wafer, the inconsistency is based on the diameter up to 3 mm from the edge of the wafer. data. The inconsistency value corresponds to the degree of change in the measured selectivity ratio between features at the relevant test location. In this example, the inconsistency value is calculated using the following formula: +/-100 x(max-min)/(2 x mean)

In the data set as a whole, "max" is the largest selection ratio in the dataset, and "min" is the smallest selectivity ratio in the dataset; and "mean" is the average selectivity ratio in the dataset.

The measurement is repeated using (i) a conventional substrate carrier, such as those described above with respect to Figures 1 and 2, and (ii) using a substrate carrier in accordance with the preferred embodiment discussed above with respect to Figure 3. get on. It can be seen that, using conventional devices (line (i)), the degree of inconsistency at 1 and 2 mm from the edge of the substrate is the degree of inconsistency obtained using the carrier (line (ii)) disclosed herein. More than twice. In the case of conventional devices, there is a significant reduction in inconsistency between 2 and 3 mm from the edge of the wafer, which represents the approximate location of the end of the exclusion zone in this region. With the carrier disclosed herein, the inconsistency in this position has a very insignificant change, which means that the process conditions are substantially uniform throughout the 1 mm, 2 mm, and 3 mm positions.

Figure 16 shows an SEM image of the etched features obtained after processing a sapphire substrate in a typical low pressure chlorination chemical plasma etching process. In Figure 16a, there are two images showing the use of a conventional sandwich-type substrate carrier (such as depicted in Figures 1 and 2) positioned at (i) 1 mm from the edge of the substrate and (ii) from the edge of the substrate. Characteristics obtained at 3 mm. It can be seen that there are very huge two locations. The etch features are different (which tend to be symmetrical) and there is a large difference in etch rate between the two locations. For example, in an image taken at 1 mm (Fig. 16a(i)), the amount of significant photoresist can still be seen, while at the 3 mm position most of it has been removed (16a(ii) Figure). This means that the etch rate is significantly less than 1 mm from the edge of the substrate at 1 mm from the edge of the substrate. Figure 16b shows a corresponding feature image produced using the substrate carrier in accordance with the embodiment of Figure 3 following the same etching process. In this case, it can be seen that at a position 1 mm from the edge of the substrate (Fig. 16b(i)) and 3 mm (Fig. 16b(ii)), the etching rate is almost the same and there is essentially no tendency to either feature. .

Accordingly, the sandwich substrate carrier disclosed herein preferably provides good thermal transfer between each wafer and the carrier plate.

Good heat transfer between the carrier plate assembly and the wafer table

Heat transfer gas (usually helium) is distributed to the back of each wafer

Convenience of assembly (fast loading of the wafer with wafers and reliable sealing of all helium gas seals)

Similar thermal transfer and RF coupling characteristics throughout the entire wafer area

Reduce the size of the exclusion area.

The backplane assembly preferably has the function of: accommodating one or more substrates on one or more top surfaces (platforms) and defining their position during processing; - (as appropriate) providing restrictions from the central region of the panel to the process a method of leaking the back side of the cooling fluid of the chamber; - (as appropriate) providing a flow path from the back of the substrate to the back side of the processing substrate (Channel); - (as appropriate) provides conditions for limited cooling fluid to leak from behind the clamped substrate to the process chamber.

The top plate preferably has the following functions: - allowing a predetermined position of the substrate to be achieved; - providing an optimal surface topography of the top surface of the assembled carrier by recessing it to a level lower than holding the substrate to position Below the member, more preferably, the portion in which the top plate adjacent to the substrate is substantially coplanar with the top surface of the substrates to thereby reduce the exclusion region; - restraining the holding member to cause a clamping force; - (as appropriate) limit the holding member to the plasma treatment.

The retaining member or retaining body preferably has the following functions: - generating individual clamping forces acting from the top of each substrate toward the bottom plate; - limiting movement of the substrate during assembly and disassembly of the carrier; - providing contact with the processing substrate The smallest surface.

4‧‧‧Substrate

20‧‧‧Substrate carrier assembly

21‧‧‧ top board

21a‧‧‧ pores

21b‧‧‧ upper surface

22‧‧‧Bottom plate assembly

23‧‧‧ platform

23a‧‧‧ surrounding recess

25‧‧‧Retaining components

25c‧‧‧ bottom side

26‧‧‧Maintaining the ontology

27‧‧‧Flange

28‧‧‧channel

Claims (58)

A substrate carrier for a plasma processing apparatus, the substrate carrier comprising: a substrate assembly including a platform on which a substrate can be placed in use, occupied by a substrate placed on the platform in use The volume constitutes a substrate region; and a top plate assembly positioned on the bottom plate assembly, the top plate assembly including a top plate and one or more retaining members having apertures therethrough and surrounding the substrate region, the one or A plurality of retention members extend into the aperture and are located on a portion of the substrate region such that, in use, the substrate disposed in the substrate region is retained in a fixed position between the backplane assembly and the top panel assembly The upper surface of the top plate facing away from the bottom plate assembly is substantially planar and the one or more retaining members project above the substantially planar upper surface of the top plate. The substrate carrier of claim 1, wherein the upper surface of the top plate is substantially coplanar with the upper surface of the substrate region. The substrate carrier of claim 2, wherein the upper surface of the top plate is coplanar with the upper surface of the substrate region in a range of plus or minus 1 mm, preferably in a range of plus or minus 0.75 mm, and More preferably, it is coplanar in the range of plus or minus 0.5 mm. The substrate carrier of claim 2, wherein the upper surface of the top plate is parallel to the upper surface of the substrate region. A substrate carrier according to any one of the preceding claims, wherein the top surface of the top plate is tied at a height from the upper surface of the platform, the height being between zero and 4 mm, preferably Between 0.25 and 3 mm, better Between 0.4 and 2 mm, and optimally between 0.4 and 1.5 mm. A substrate carrier according to any one of the preceding claims, wherein the size of the aperture is selected such that any lateral gap between the top plate and the substrate region is 2 mm or less. A substrate carrier according to any one of the preceding claims, wherein the top plate assembly comprises a plurality of retaining members spaced apart from each other about the aperture, and preferably spaced equidistant from one another. A substrate carrier according to any one of the preceding claims, wherein the retaining member is an integral part of the top plate and the retaining members are in a fixed relationship to one another. The substrate carrier of any one of claims 1 to 7, wherein the top plate and the holding member are flexibly coupled with respect to each other. The substrate carrier of claim 9, wherein the holding member is carried on the top plate via one or more elastic connectors. The substrate carrier of claim 9, wherein the holding member is carried by the holding body, the holding system is separated from the top plate, and the holding member preferably forms an integral part of the holding body. The substrate carrier of claim 11, wherein the top plate is configured to contact the holding body at one or more contact portions of the holding body, the contact portion being elastically coupled to the holding member such that The advancement of the top plate toward the bottom plate assembly causes elastic deformation of the elastic connecting member. The substrate carrier of claim 12, wherein each of the holding members on the holding body preferably has an elastic connecting member having one or more of them substantially independent of the other The contact portion of the resilient connector of the retaining member. The substrate carrier of claim 12 or 13, wherein the retaining body comprises a flange disposed between the top plate and the base plate assembly such that, in use, the flange is by the top plate It is advanced toward the bottom plate assembly and has an elastic connection between the flange and the retaining member. The substrate carrier of claim 14 wherein the resilient connector comprises a joint between the flange and the retaining body, the flange being biased toward the top plate such that the top plate is opposite the bottom plate The assembly pressure will cause elastic deformation of the flange around the joint. The substrate carrier of claim 14, wherein the resilient connector comprises an extension spring extending between the flange and the retaining member, the extended spring preferably forming an integral portion of the retaining body. The substrate carrier of any one of claims 10 to 16, wherein the retention system is shaped to substantially conform to the periphery of the substrate region, the retention body preferably being substantially cylindrical or truncated Conical, the one or more retaining members extend inwardly toward the interior of the cylinder or frustum, and the flange extends outwardly away from the interior of the cylinder or frustum. The substrate carrier of claim 17, wherein the holding body comprises one or more flanges disposed between the top plate and the bottom plate assembly such that the flange is used by the flange The top plate is advanced toward the bottom plate assembly and has an elastic connection between the flange and the retaining member, wherein the resilient connector also has the same symmetry as the substrate region, and preferably is rotationally symmetric . A substrate carrier according to any one of the preceding claims, wherein the or each holding member has a dimension of 3 mm or less in a direction parallel to a normal to the substrate region. The maximum height, and preferably has a maximum height of 2 mm or less. A substrate carrier according to any one of the preceding claims, wherein the or each retaining member extends over the substrate area by 3 mm or less from the top plate, and preferably 2 mm or more from the top plate. small. The substrate carrier of any one of the preceding claims, wherein the total area of the substrate region covered by the one or more holding members is 2% or less of the total area of the substrate region, and is preferably The ground system is 0.5% or less. A substrate carrier according to any one of the preceding claims, wherein the platform protrudes relative to its surrounding portion on the base plate and preferably extends into the aperture provided in the top plate. A substrate carrier according to any one of the preceding claims, wherein the platform has essentially the same lateral shape as the substrate region. The substrate carrier of any one of claims 10 to 23, wherein the platform is surrounded by one or more recesses in the bottom plate and the one or more recesses are for receiving the retaining body. A substrate carrier according to any one of the preceding claims, wherein the platform has one or more passages therethrough to allow transfer of heat transfer fluid to the bottom side of the substrate disposed in the substrate region during use. And/or removing the heat transfer fluid from the bottom side of the substrate. A substrate carrier according to any one of the preceding claims, wherein the bottom plate assembly extends below the top plate assembly on the outside of the platform and has one or more passages therethrough to allow transfer The heat transfer fluid is removed to the bottom side of the top plate assembly and/or the heat transfer fluid is removed from the bottom side of the top plate assembly. For example, the substrate carrier of claim 25, wherein the platform is further A projecting end edge disposed about the platform is included, whereby in use, the substrate disposed on the projecting end edge defines a volume for supplying a heat transfer fluid between a bottom side of the substrate and the platform . The substrate carrier of claim 25 or 27, wherein the bottom plate assembly further comprises an elastic seal disposed in a recess extending around the platform, whereby the seal is placed on the seal during use. The substrate defines a sealed volume for supplying a heat transfer fluid between the bottom side of the substrate and the platform. The substrate carrier of any one of claims 25 to 28, wherein the bottom plate assembly further comprises an elastic seal disposed on a lower surface of the bottom plate assembly, whereby the bottom plate assembly is used when in use The placement on the substrate table defines a sealed volume for supplying a heat transfer fluid between the bottom side of the base plate assembly and the substrate table. The substrate carrier of claim 28 or 29, wherein the elastic seal comprises an O-ring. The substrate carrier of any one of claims 28 to 30, wherein the elastic seal has a Xiao hardness A of 60 or less. A substrate carrier according to any of the preceding claims, wherein the substrate assembly comprises an electrically or thermally conductive material, preferably aluminum or an aluminum alloy. A substrate carrier according to any of the preceding claims, wherein the top plate assembly comprises an electrically or thermally conductive material, preferably aluminum or an aluminum alloy. A substrate carrier according to any one of the preceding claims, wherein the holding body comprises an electrically or thermally conductive material, preferably aluminum or an aluminum alloy. A substrate carrier according to any one of the preceding claims, further comprising The top plate assembly is pushed against the connector of the bottom plate assembly. The substrate carrier of claim 35, wherein the connector comprises a clamping assembly or bolt assembly configured to urge the top plate assembly against the bottom plate assembly. The substrate carrier of any one of the preceding claims, wherein the bottom plate assembly for carrying a plurality of substrates comprises a plurality of platforms, each platform is used to support one substrate, and each platform defines a respective substrate. a region, and the top plate has a plurality of apertures positioned to correspond to the respective substrate regions, at least one retention member extending from the top plate into each of the apertures and located on a portion of each respective substrate region. The substrate carrier of claim 37, wherein the holding member extending into each of the apertures is carried on the respective holding body, and A holding body is provided for each aperture. The substrate carrier of claim 37 or 38, wherein the plurality of platforms form a portion for joining the bottom plates of the platforms. A substrate carrier assembly comprising the substrate carrier of any one of claims 1 to 39 and at least one substrate disposed in the substrate region and defining the substrate region. The substrate carrier assembly of claim 40, wherein the at least one substrate is a dielectric substrate, preferably a sapphire substrate. A plasma processing apparatus comprising the substrate carrier of any one of claims 1 to 39 or the substrate carrier assembly of claim 40 or 41. The plasma processing apparatus of claim 42, further comprising a substrate stage and a platform connector, the substrate carrier being disposed on the substrate stage, wherein the platform connector is preferably a clamping configuration or a bolt configuration And for pushing the substrate carrier against the substrate stage. A method of fabricating a substrate carrier for a plasma processing apparatus, the method comprising: selecting a size of a substrate to be carried by the substrate carrier; providing a substrate assembly comprising: configured to have the selected one in use a platform on which the sized substrate is placed, the volume occupied by the substrate placed on the platform in use constitutes the substrate area of the selected size; and a top plate assembly positioned on the bottom plate assembly, The top plate assembly includes one or more retention members having apertures therethrough and surrounding the top plate of the substrate region and extending into the aperture, the one or more retention members being located on a portion of the substrate region such that, in use, a substrate disposed in the substrate region is held in a fixed position between the bottom plate assembly and the top plate assembly; wherein an upper surface of the top plate facing away from the bottom plate assembly is substantially planar, and the one Or a plurality of retaining members projecting over the substantially planar upper surface of the top plate. The method of claim 44, wherein the upper surface of the top plate is substantially coplanar with the upper surface of the substrate region. The method of claim 45, wherein the upper surface of the top plate is coplanar with the upper surface of the substrate region in a range of plus or minus 1 mm, preferably in the range of plus or minus 0.75 mm, and more preferably Coplanar in the range of plus or minus 0.5 mm. The method of claim 45, wherein the top surface of the top plate is parallel to the upper surface of the substrate region. The method of any one of claims 44 to 47, wherein the size of the aperture is selected such that any gap between the top plate and the substrate region is 2 mm or less. The method of any one of claims 44 to 48, further comprising providing any of the features of claims 1 to 43 of the patent application. A method of mounting a substrate for plasma processing, comprising: placing the substrate on a platform forming a portion of a backplane assembly; and placing a top plate assembly on the bottom plate assembly, the top plate assembly including a top plate and One or more retention members having apertures therethrough and surrounding the substrate region, the one or more retention members extending into the aperture and on a portion of the substrate region such that, in use, the substrate is Maintaining a fixed position between the bottom plate assembly and the top plate assembly; wherein an upper surface of the top plate facing away from the bottom plate assembly is substantially planar, and the one or more retaining members protrude from the top plate This is essentially above the planar upper surface. The method of claim 50, wherein the upper surface of the top plate is substantially coplanar with the upper surface of the substrate region. The method of claim 51, wherein the upper surface of the top plate is coplanar with the upper surface of the substrate region in a range of plus or minus 1 mm, preferably in the range of plus or minus 0.75 mm, and more preferably Coplanar in the range of plus or minus 0.5 mm. The method of claim 51, wherein the top surface of the top plate It is parallel to the upper surface of the substrate. The method of any one of claims 50 to 53, wherein the size of the aperture is selected such that any gap between the top plate and the substrate is 2 mm or less. The method of any one of claims 50 to 54, wherein the holding member is carried by the holding body, the holding system being separated from the top plate, the holding member preferably being formed as a whole of the holding body And partially comprising placing the retaining body on the base plate assembly, the retaining member extending partially over the base plate and then placing the top plate on the retaining body. The method of claim 55, wherein the holding body conforms to a shape of the periphery of the substrate such that placing the holding body on the substrate causes the substrate to be centered relative to the platform. The method of any one of claims 50 to 56, wherein a plurality of substrates are installed for plasma processing, the method further comprising, prior to placing the top plate assembly on the bottom plate assembly, Each of the plurality of substrates is first placed on a respective platform of the backplane assembly. The method of claim 55 and 57, wherein a plurality of corresponding holding bodies are provided, and the system is placed on the bottom plate assembly, and the top plate is placed on the plurality of holding bodies. Previously, the retaining member partially extended over each of the respective substrates.