Apparatus and method for controlling chucking force

Abstract

A chucking force control device according to an embodiment of the present invention comprises a chuck on which a substrate is disposed on an upper surface, a fixing part that generates a chucking force to fix the substrate to the chuck in a first direction perpendicular to the upper surface of the chuck and applies the chucking force to the substrate, and a controller that divides the chuck into a plurality of zones on a plane perpendicular to the first direction based on a reference overlay distribution corresponding to the degree of overlay degradation when fixing the substrate to the upper surface of the chuck, and controls the chucking force individually for the plurality of zones. The controller can reduce the magnitude of the chucking force applied to a zone including an area with a large degree of overlay degradation among the plurality of zones in the reference overlay distribution. Accordingly, by using a chucking force control device according to an embodiment of the present invention, a substrate in a process facility can be fixed to the chuck, and the flatness of the substrate surface can be improved in response to the problem of overlay degradation.

Description

Technology Field

[0001] The present invention relates to a chucking force control device and method. Background Technology

[0003] Semiconductor processes can be performed on wafers placed on a wafer stage. A chucking force control device controls the chucking force applied to the wafer stage to secure the wafer within the semiconductor process equipment and maintain the flatness of the wafer surface. Meanwhile, as semiconductor devices become highly integrated and semiconductor processes become miniaturized, various types of process defects are occurring during semiconductor processes performed by placing wafers on the upper surface of a wafer stage. For example, as the flatness of the wafer surface deteriorates, defects such as overlay defects may occur on the wafer. The problem to be solved

[0005] One of the objectives of the technical concept of the present invention is to solve the problem of overlay degradation and maintain the flatness of the substrate surface by controlling the chucking force applied to the substrate based on the overlay distribution, and furthermore, to improve the production yield of the semiconductor device. means of solving the problem

[0007] A chucking force control device according to one embodiment of the present invention comprises a chuck on which a substrate is disposed on an upper surface, a fixing part that generates a chucking force to fix the substrate to the chuck in a first direction perpendicular to the upper surface of the chuck and applies the chucking force to the substrate, and a controller that divides the chuck into a plurality of zones on a plane perpendicular to the first direction based on a reference overlay distribution corresponding to the degree of overlay degradation when fixing the substrate to the upper surface of the chuck, and controls the chucking force individually for the plurality of zones, wherein the controller reduces the magnitude of the chucking force applied to a zone including a region with a large degree of overlay degradation among the plurality of zones in the reference overlay distribution.

[0009] A chucking force control device according to one embodiment of the present invention comprises a chuck having a substrate disposed on its upper surface, a fixing part that generates a chucking force to fix the substrate to the chuck and applies the chucking force to the substrate, and a controller that divides the chuck into a plurality of zones and controls the chucking force individually for the plurality of zones, wherein the plurality of zones include a first zone including a center of the chuck, a second zone including a region in a first angle direction with respect to the center of the chuck, a third zone including a region in a second angle direction different from the first angle with respect to the center of the chuck, and a fourth zone disposed at a different position from the first zone in the radial direction of the chuck, wherein the second zone and the third zone are disposed between the first zone and the fourth zone.

[0011] A chucking force control method according to one embodiment of the present invention comprises the steps of: measuring a reference overlay distribution corresponding to the degree of overlay degradation when fixing a substrate to the upper surface of a chuck; dividing the chuck into a plurality of zones based on the reference overlay distribution; controlling a chucking force individually for the plurality of zones; and fixing the substrate to the chuck using the chucking force. Effects of the invention

[0013] A chucking force control device according to one embodiment of the present invention can divide the chuck into a plurality of zones based on an overlay distribution and individually control the chucking force applied to the substrate for the plurality of zones.

[0014] A chucking force control device according to one embodiment of the present invention can solve the overlay degradation problem and improve the production yield of a semiconductor device.

[0015] The various and beneficial advantages and effects of the present invention are not limited to those described above and will be more easily understood in the process of explaining specific embodiments of the present invention. Brief explanation of the drawing

[0017] FIG. 1 is a simplified diagram illustrating semiconductor process equipment to which a chucking force control device according to one embodiment of the present invention is applied. FIG. 2 is a simplified diagram of a chucking force control device according to one embodiment of the present invention. FIGS. 3 and 4 are drawings for explaining the operating principle of a fixed part in a chucking force control device according to one embodiment of the present invention. FIG. 5 is a flowchart illustrating a chucking force control method according to an embodiment of the present invention. FIG. 6 is a simplified drawing of a chucking force control device according to another embodiment of the present invention. FIG. 7 is a flowchart illustrating a chucking force control method according to another embodiment of the present invention. FIG. 8 is a diagram illustrating an overlay degradation problem that can be solved by a chucking force control device according to an embodiment of the present invention. FIG. 9 is a diagram illustrating the cause of an overlay degradation problem that can be solved by a chucking force control device according to an embodiment of the present invention. FIGS. 10a to 10c are drawings for explaining the cause of an overlay degradation problem that can be solved by a chucking force control device according to an embodiment of the present invention. FIG. 11 is a diagram illustrating the operating principle of a chucking force control device according to an embodiment of the present invention. FIG. 12 is a drawing for explaining the features of a substrate to which a chucking force control device according to one embodiment of the present invention is applied. FIG. 13 is a drawing for explaining a plurality of zones in a chucking force control device according to one embodiment of the present invention. FIGS. 14 and 15 are drawings for explaining a fixing part included in a chucking force control device according to one embodiment of the present invention. FIG. 16 is a drawing for explaining the effects of a chucking force control device according to one embodiment of the present invention. FIG. 17 is a drawing for explaining a plurality of zones in a chucking force control device according to one embodiment of the present invention. FIG. 18 is a drawing for explaining a plurality of zones in a chucking force control device according to one embodiment of the present invention. FIG. 19 is a drawing for explaining a plurality of zones in a chucking force control device according to one embodiment of the present invention. FIG. 20 is a drawing for explaining a plurality of zones in a chucking force control device according to one embodiment of the present invention. Specific details for implementing the invention

[0018] Hereinafter, preferred embodiments of the present invention are described as follows with reference to the attached drawings.

[0020] In the drawings and specifications, terms such as "first," "second," and "third" may be used to describe various components, but said components may not be limited by said terms. Terms such as "first," "second," and "third" may be used for the purpose of distinguishing any one component from another. For example, without departing from the scope of the present invention, "first component" may be named "second component."

[0022] FIG. 1 is a simplified diagram illustrating semiconductor process equipment to which a chucking force control device according to one embodiment of the present invention is applied.

[0023] Referring to FIG. 1, a semiconductor process equipment (1) to which a chucking force control device according to one embodiment of the present invention is applied may include a plurality of process chambers (11-14; 10) for performing semiconductor processes on a substrate (W). For example, the plurality of process chambers (10) may include a deposition process chamber for performing a deposition process, a polishing process chamber for performing a chemical mechanical polishing (CMP) process, an etching process chamber for removing at least some of the device layers included in the substrate (W) by generating a plasma containing radicals and ions of a source gas or using an etching solution, and a photolithography process chamber for lithographing circuits and patterns on the substrate (W). Meanwhile, the plurality of process chambers (10) may include a test process chamber for inspecting the substrate (W) during the process or after the process is completed.

[0024] For example, the substrate (W) may be a semiconductor substrate on which a semiconductor process is performed, or a wafer formed from a semiconductor material such as silicon. Semiconductor devices, wiring patterns connected to the semiconductor devices, and insulating layers covering the semiconductor devices and wiring patterns may be formed on the substrate (W) by semiconductor processes performed in a plurality of process chambers (10), and a plurality of semiconductor chips may be produced from the substrate (W).

[0025] For example, a plurality of process chambers (11-14) can receive a substrate (W) through a transfer chamber (20) and a load lock chamber (40) and perform a semiconductor process. The transfer chamber (20) and the load lock chamber (40) may include a transfer robot (30), and the transfer robot (30) of the transfer chamber (20) and the load lock chamber (40) can transfer the substrate (W), etc., which is the process target. For example, the transfer robot (30) of the transfer chamber (20) can take the process target, such as the substrate (W), out of the load lock chamber (40) and transfer it to a plurality of process chambers (11-14), or transfer the process target between a plurality of process chambers (11-14). In one embodiment, the transfer robot may be a handler.

[0026] The transfer robot (30) may include a chuck for fixing a process target and a linear stage for transferring the process target. For example, the chuck may be a wafer stage on which a wafer is placed.

[0027] For example, the chuck may be an electrostatic chuck (ESC) that fixes a process target using electrostatic force. During a process such as an exposure process in a semiconductor process equipment (1) to which a chucking force control device according to an embodiment of the present invention is applied, the chuck may fix a process target, such as a substrate (W), to a predetermined position using electrostatic force. For example, the predetermined position may include both a position in the up-down direction and a position in the left-right direction. A plurality of protrusions that contact the process target may be formed on the upper surface of the electrostatic chuck. Depending on the process, the electrostatic chuck may operate as a lower electrode. However, this is merely one embodiment and is not limited thereto.

[0028] Meanwhile, the chuck for fixing the process object may be a vacuum chuck that fixes the process object using suction force. The vacuum chuck can fix the substrate (W) to the upper surface of the vacuum chuck by sucking in gas between it and the process object.

[0029] Referring to FIG. 1, in a semiconductor process equipment (1) to which a chucking force control device according to one embodiment of the present invention is applied, a transfer robot (30) of a transfer chamber (20) can take a substrate (W) out of a load lock chamber (40) and transfer it to the transfer chamber (20), and transfer the substrate (W) to be processed to a process chamber (11).

[0030] For example, the process chamber (11) may be a photo process chamber in which an exposure process is performed, and an exposure process may be performed on a substrate (W) to be processed within the process chamber (11). However, depending on the embodiments, the target of the process may not be limited to a wafer. For example, the substrate (W) may be various substrates other than a wafer, such as a mother substrate for a display.

[0031] A substrate (W) transferred to a process chamber (11) can be fixed to the upper surface of a chuck (110) while the process is in progress. For example, the process chamber (11) may include a first region (11a) and a second region (11b). The first region (11a) may be a region for measuring an overlay distribution indicating the degree of overlay degradation when the substrate (W) is fixed to the upper surface of the chuck (110). The second region (11b) may be a region for performing an exposure process on the substrate (W). The substrate (W) transferred to the process chamber (11) may be transferred to the second region (11b) via the first region (11a), and an exposure process may be performed. However, this is merely one embodiment and is not limited to this.

[0032] A chucking force control device according to one embodiment of the present invention can fix a substrate (W) to the upper surface of a chuck (110) using a fixing part. The chucking force control device can divide the chuck (110) into a plurality of zones and control the magnitude of the chucking force individually for the plurality of zones. The chucking force can be applied to the substrate (W) corresponding to the plurality of zones, and based on the applied chucking force, the substrate (W) can be fixed to the upper surface of the chuck (110) while maintaining flatness. For example, the chucking force can be defined as a fixing force.

[0034] FIG. 2 is a simplified diagram of a chucking force control device according to one embodiment of the present invention.

[0035] Referring to FIG. 2, a chucking force control device (100) according to one embodiment of the present invention may include a chuck (110), a fixing part (120), and a controller (130). The chucking force control device (100) may be applied to at least one of a plurality of process chambers (11-14) shown in FIG. 1. The chuck (110) and the fixing part (120) may be placed inside the process chamber (101), and the controller (130) may be placed outside the process chamber (101).

[0036] A substrate (W) may be placed on the upper surface of the chuck (110). The fixing part (120) may generate a chucking force to fix the substrate (W) to the chuck (110) in a first direction (e.g., Z direction) perpendicular to the upper surface of the chuck (110). The fixing part (120) may apply the chucking force to the substrate (W). The fixing part (120) may be placed between the chuck (110) and the substrate (W), but this is merely one embodiment and is not limited thereto, and the fixing part (120) may be a configuration included inside the chuck (110).

[0037] Meanwhile, when fixing the substrate (W) to the upper surface of the chuck (110), the substrate (W) may not be fixed perfectly flat to the upper surface of the chuck (110). For example, the substrate (W) may be fixed to the upper surface of the chuck (110) with curvature in some areas. Curvature occurring in the substrate (W) during the semiconductor process can reduce the accuracy of the process. For example, overlay problems related to pattern alignment may occur, such as the inability to perform the process at the correct location on the substrate (W).

[0038] The controller (130) can divide the chuck (110) into a plurality of zones on a plane perpendicular to the first direction based on the degree of overlay degradation when fixing the substrate (W) to the upper surface of the chuck (110). For example, the degree of overlay degradation may be a reference overlay distribution determined from a previously measured overlay distribution. However, this is merely one embodiment and is not limited to.

[0039] The controller (130) can control the chucking force individually for multiple zones. The controller (130) can detect areas with a high degree of overlay degradation based on a reference overlay distribution. The controller (130) can reduce the magnitude of the chucking force applied to the zones containing the areas with a high degree of overlay degradation among the multiple zones.

[0041] FIGS. 3 and 4 are drawings for explaining the operating principle of a fixed part in a chucking force control device according to one embodiment of the present invention.

[0042] The chuck (110) included in the chucking force control device (100) according to one embodiment of the present invention may be an electrostatic chuck (ESC) or a vacuum chuck. Depending on the type of chuck (110), the shape and operating principle of the fixed part (120) may vary. However, FIGS. 3 and 4 are merely drawings for explaining the operating principle of the fixed part (120) according to the type of chuck (110), and the shape may not be limited to that shown.

[0043] Referring to FIG. 3, the electrostatic chuck (110A) may include an electrode portion (120A) that includes a plurality of electrodes within it. For example, the electrode portion (120A) may include a positive electrode and a negative electrode, and the electrode portion (120A) may generate an electrical attractive force between itself and the lower surface of the substrate (W) by applying an electrical signal to the plurality of electrodes. Accordingly, the electrode portion (120A) can fix the substrate (W) onto the electrostatic chuck (110A) using a chucking force composed of the electrical attractive force.

[0044] Referring to FIG. 4, the vacuum chuck (110B) may include a suction portion (120B) containing a plurality of holes therein. For example, the suction portion (120B) can create a vacuum between the substrate (W) and the vacuum chuck (110B) through the plurality of holes. Accordingly, the electrode portion (120A) can fix the substrate (W) onto the vacuum chuck (110B) using the chucking force generated by the pressure difference.

[0046] FIG. 5 is a flowchart illustrating a chucking force control method according to an embodiment of the present invention.

[0047] As described above in the description of FIG. 2, a chucking force control device (100) according to one embodiment of the present invention can divide the chuck (110) into a plurality of zones based on the degree of overlay degradation when a substrate (W) is fixed to the upper surface of the chuck (110), and can solve the overlay degradation problem by controlling the chucking force individually for the plurality of zones.

[0048] Referring to FIG. 5, a chucking force control method according to one embodiment of the present invention may begin by measuring a reference overlay distribution corresponding to the degree of overlay degradation when a substrate (W) is fixed to the upper surface of a chuck (110) (S110).

[0049] A controller (130) included in the chucking force control device (100) can divide the chuck (110) into multiple zones based on a measured reference overlay distribution (S120). For example, the multiple zones may include zones positioned at different locations in the radial direction of the chuck (110) and zones positioned at different locations in the angular direction of the chuck (110).

[0050] The controller (130) can individually control the chucking force, such as the fixing force, applied to a plurality of divided zones (S130). A chucking force control device (100) according to one embodiment of the present invention can fix the substrate (W) to the upper surface of the chuck (110) while maintaining the flatness of the substrate (W) by individually applying the chucking force to a plurality of zones according to the chucking force control method (S140).

[0052] FIG. 6 is a simplified drawing of a chucking force control device according to another embodiment of the present invention.

[0053] Referring to FIG. 6, the configuration of a chucking force control device (200) according to another embodiment of the present invention may correspond to the chucking force control device (100) shown in FIG. 2. For example, the chucking force control device (200) may include a chuck (210) on which a substrate (W) is placed on an upper surface, a fixing part (220) that generates a chucking force to fix the substrate (W) to the chuck (210), and a controller (230) that controls the chucking force by zone to solve the overlay degradation problem.

[0054] Meanwhile, unlike the chucking force control device (100) shown in FIG. 2, the chucking force control device (200) according to one embodiment of the present invention may further include an overlay distribution measuring device (240) for measuring the degree of overlay degradation of the substrate (W) before, during, or after the process. For example, the overlay distribution measuring device (240) may measure a target overlay distribution different from a reference overlay distribution and transmit the measurement result to a controller (230).

[0055] The controller (230) can set up new multiple zones based on the target overlay distribution. The controller (230) can control the chucking force individually for the new multiple zones.

[0056] Meanwhile, the chucking force control device (100) illustrated in FIG. 2 is shown as not including a configuration corresponding to the overlay distribution measuring device (240), but this is merely one embodiment and is not limited. For example, the chucking force control device (100) may include a separate configuration corresponding to the overlay distribution measuring device (240) to measure a reference overlay distribution for setting multiple zones.

[0058] FIG. 7 is a flowchart illustrating a chucking force control method according to another embodiment of the present invention.

[0059] Referring to FIG. 7, steps S210 to S230 included in the chucking force control method according to another embodiment of the present invention may correspond to steps S110 to S130 of the chucking force control method illustrated in FIG. 5, respectively. For example, the chucking force control method may begin by measuring a reference overlay distribution corresponding to the degree of overlay degradation when fixing a substrate (W) to the upper surface of the chuck (210) (S210). A controller (230) included in the chucking force control device (200) may divide the chuck (210) into a plurality of zones based on the measured reference overlay distribution (S220), and may individually control the chucking force, such as a fixing force, applied to the divided plurality of zones (S230).

[0060] However, according to the chucking force control method illustrated in FIG. 7, the chucking force control device (200) may measure the target overlay distribution using an overlay distribution measuring device (240) before, during, or after the process (S240). The overlay distribution measuring device (240) may transmit the measured target overlay distribution to the controller (230).

[0061] The controller (230) can determine whether to reset multiple zones based on the received target overlay distribution (S250). If necessary, the controller (230) can re-divide the zones based on the target overlay distribution (S260) and control the chucking force individually for the re-divided multiple zones (S270).

[0062] A chucking force control device (200) according to one embodiment of the present invention can fix a substrate (W) to the upper surface of a chuck (210) while maintaining the flatness of the substrate (W) by a chucking force that is individually controlled for a plurality of zones set based on a reference overlay distribution or a new plurality of zones set based on a target overlay distribution, according to a chucking force control method (S280).

[0064] FIG. 8 is a diagram illustrating an overlay degradation problem that can be solved by a chucking force control device according to an embodiment of the present invention.

[0065] FIG. 8 may be an overlay distribution when the chuck is not divided into multiple zones and the chucking force is applied evenly over the entire surface. However, the overlay distribution may not be limited to what is shown in FIG. 8. For example, the overlay distribution may vary depending on the strength of the chucking force applied to the substrate, and if the process on the substrate is prolonged, the overlay distribution may change due to increased friction between the chuck and the substrate. In addition, the overlay distribution may be determined by various causes such as the anisotropy of the material constituting the substrate, warpage, the pattern of the chip formed on the substrate, and scribe lanes.

[0066] Referring to Fig. 8, the overlay distribution may appear as concentric circles overall. For example, there may be almost no overlay degradation in the area corresponding to the center of the chuck, but overlay degradation may worsen as it moves further away from the center of the chuck. On the other hand, if it moves further away from the center of the chuck beyond a certain level, the degree of overlay degradation may decrease again, and overlay degradation may appear relatively large in the area corresponding to the outer edge of the chuck.

[0067] Meanwhile, the overlay distribution may vary depending on the angle direction. For example, near the outer edge of the chuck where overlay degradation is severe, the overlay degradation may worsen every 90°. In this case, the second overlay degradation area (OL2) may be located in the first angle direction. On the other hand, near the center and outer edge of the chuck where overlay degradation is severe, the overlay degradation may worsen every 90°. In this case, the first overlay degradation area (OL1) may be located in the second angle direction.

[0068] In FIG. 8, the first overlay deterioration region (OL1) may be located in a direction intersecting the second direction (e.g., X direction) and the third direction (e.g., Y direction), and the second overlay deterioration region (OL2) may be located in the second direction and the third direction. A chucking force control device according to one embodiment of the present invention may operate to compensate for the deterioration of the first overlay deterioration region (OL1) and the second overlay deterioration region (OL2).

[0070] FIG. 9 is a diagram illustrating the cause of an overlay degradation problem that can be solved by a chucking force control device according to an embodiment of the present invention.

[0071] FIG. 9 may be a diagram illustrating an overlay degradation problem caused by non-uniform contact pressure when a uniform chucking force is applied to a substrate (W). For example, the overlay degradation problem illustrated in FIG. 9 may be an overlay degradation appearing in the radial direction of the substrate (W).

[0072] While the lower surface of the substrate (W) is in contact with the chuck (110), the substrate (W) may be subjected to tensile stress (FT) or compressive stress (FC) depending on the degree of deformation. With the chucking force applied, the deformation of the substrate (W) may gradually accumulate from the center toward the outer edge of the substrate (W). Consequently, as the contact pressure becomes locally concentrated in some areas, the stress on the substrate (W) is not relieved, and an overlay degradation problem may occur in the concentrated area.

[0073] Referring to FIG. 8 and FIG. 9 together, the first overlay degradation area (OL1) may illustrate an overlay degradation problem occurring in a concentric area having a first radius (r1), and the second overlay degradation area (OL2) may illustrate an overlay degradation problem occurring in a concentric area having a second radius (r2).

[0075] FIGS. 10a to 10d are drawings for explaining the cause of an overlay degradation problem that can be solved by a chucking force control device according to an embodiment of the present invention.

[0076] FIGS. 10a to 10c may be drawings for explaining an overlay degradation problem caused by the anisotropy of the material constituting the substrate (W). For example, the overlay degradation problem illustrated in FIGS. 10a to 10d may be an overlay degradation appearing in the angular direction of the substrate (W).

[0077] Referring to FIG. 10a and FIG. 10b, the modulus of elasticity of the substrate (W) may vary depending on the crystal direction of the material constituting the substrate (W). The modulus of elasticity of the substrate (W) may be directly related to the deformation force of the substrate (W). The deformation force of the substrate (W) may be represented by arrows, and the lengths of the arrows may correspond to the magnitude of the deformation force.

[0078] For example, the angle between the AA' direction and the BB' direction may be approximately 45°. The deformation force of the substrate (W) in the AA' direction may be weaker than the deformation force of the substrate (W) in the BB' direction. Therefore, the substrate (W) may have higher stiffness at the PA point located in the AA' direction than at the PB point located in the BB' direction, and thus a higher restoring force to resist deformation. At the PB point located in the BB' direction, due to the relatively lower restoring force, deformation and overlay deterioration caused by the concentration of contact pressure may occur more easily than at the PA point.

[0079] Referring to FIG. 10c, the first restoring force (FRA) at point PA of the substrate (W) may be greater than the second restoring force (FRB) at point PB. Meanwhile, the frictional force (Ff) between the substrate (W) and the chuck (110) is proportional to the normal force, and the normal force can be determined by the chucking force applied to the substrate (W). Therefore, if the chucking force applied to the substrate (W) is uniform overall, the frictional force (Ff) between the substrate (W) and the chuck (110) may be at the same level at point PA and point PB.

[0080] At the PA point of the substrate (W), the magnitude of the first restoring force (FRA) against deformation is large due to the relatively high stiffness, so the frictional force (Ff) can be offset. Therefore, at the PA point of the substrate (W), the likelihood of deformation and overlay degradation problems of the substrate (W) occurring is relatively low.

[0081] On the other hand, at the PB point of the substrate (W), the magnitude of the second restoring force (FRB) against deformation is small due to the relatively low stiffness, so it may not be sufficient to offset the frictional force (Ff). Therefore, at the PB point of the substrate (W), there is a relatively high possibility that problems of deformation and overlay degradation of the substrate (W) may occur.

[0083] FIG. 11 is a diagram illustrating the operating principle of a chucking force control device according to an embodiment of the present invention.

[0084] Referring to FIG. 11, a chucking force control device according to one embodiment of the present invention can reduce the likelihood of overlay degradation problems by individually controlling the chucking force applied at the PB point, where deformation of the substrate (W) and overlay degradation problems are relatively likely to occur.

[0085] The forces acting between the substrate (W) and the chuck (110) shown in FIG. 11 may correspond to the forces acting between the substrate (W) and the chuck (110) at the PB point shown in FIG. 10c. For example, at the PB point of the substrate (W), a second restoring force (FRB) against deformation may be applied, and if the second restoring force (FRB) fails to offset the frictional force (Ff') between the substrate (W) and the chuck (110), an overlay deterioration problem may occur on the substrate (W).

[0086] Meanwhile, the frictional force (Ff') between the substrate (W) and the chuck (110) is proportional to the normal force, and the normal force can correspond to the chucking force applied to the substrate (W). A chucking force control device according to one embodiment of the present invention can reduce the frictional force (Ff') by reducing the chucking force applied to the substrate (W) at point PB. Accordingly, the chucking force control device can improve the deformation and overlay deterioration of the substrate (W) by allowing the substrate (W) to slide relatively easily on the chuck (110).

[0088] FIG. 12 is a drawing for explaining the features of a substrate to which a chucking force control device according to one embodiment of the present invention is applied.

[0089] Referring to the description in FIGS. 9 to 11, the substrate (W) may include a region that is relatively weak to overlay degradation depending on the radial direction and the angular direction. Referring to FIG. 12, the substrate (W) may include a region that is relatively weak to overlay degradation between a region corresponding to the center of the substrate (W) in the radial direction and a region corresponding to the outer edge of the substrate (W). Meanwhile, the substrate (W) may include a region that is relatively weak to overlay degradation near the PB point where the restoring force is relatively weak in the angular direction.

[0090] Therefore, the vulnerable area (WW) including the PB point may be more likely to experience overlay degradation problems compared to other areas. A chucking force control device according to one embodiment of the present invention can solve the overlay degradation problem by reducing the chucking force applied to areas where the overlay degradation problem is likely to occur, such as the vulnerable area (WW).

[0092] FIG. 13 is a drawing for explaining a plurality of zones in a chucking force control device according to one embodiment of the present invention.

[0093] Referring to FIG. 13, a chucking force control device according to one embodiment of the present invention can divide the chuck (310) into a plurality of zones (R1, R2, R3, R4) based on a reference overlay distribution and / or a target overlay distribution.

[0094] A plurality of zones (R1, R2, R3, R4) may include a first zone (R1) and a fourth zone (R4) positioned at different locations in the radial direction of the chuck (310), and a second zone (R2) and a third zone (R3) positioned at different locations in the angular direction of the chuck (310).

[0095] For example, the first zone (R1) may be defined at a position corresponding to the center of the chuck (310), and the fourth zone (R4) may be defined at a position corresponding to the outer edge of the chuck (310), and the first zone (R1) and the fourth zone (R4) may be spaced apart from each other. The second zone (R2) and the third zone (R3) may be defined at a position corresponding to the outside of the first zone (R1), and the second zone (R2) and the third zone (R3) may be positioned between the first zone (R1) and the fourth zone (R4).

[0096] Meanwhile, the second zone (R2) may be separated from the first zone (R1) and include an area in the first angle direction, and the third zone (R3) may be separated from the first zone (R1) and include an area in the second angle direction different from the first angle.

[0097] In a plurality of zones (R1, R2, R3, R4) set by a chucking force control device according to one embodiment of the present invention, at least one of a second zone (R2) and a third zone (R3) may be disposed between a first zone (R1) and a fourth zone (R4) in at least one of the directions parallel to the upper surface of the chuck (310).

[0098] Meanwhile, at least three of the first to fourth zones (R1, R2, R3, R4) may be arranged in at least one of the directions parallel to the upper surface of the chuck (310). For example, in the second direction (e.g., X direction) and the third direction (e.g., Y direction), the first zone (R1), the second zone (R2), and the fourth zone (R4) may be sequentially located outward from the center of the chuck (310). Additionally, in the direction intersecting the second direction and the third direction, the first zone (R1), the second zone (R2), the third zone (R3), and the fourth zone (R4) may be sequentially located outward from the center of the chuck (310).

[0099] At least one of the plurality of zones (R1, R2, R3, R4) set by the chucking force control device according to one embodiment of the present invention may include a plurality of sub-zones individually controlled by a controller.

[0100] For example, among the plurality of zones (R1, R2, R3, R4) in the chuck (310) illustrated in FIG. 13, the second zone (R2) may be extended in a second direction and a third direction with respect to the center of the chuck (310), and accordingly, the third zone (R3) may include a plurality of third zones (R3) arranged between the second zone (R2) and the fourth zone (R4) in a direction parallel to the upper surface of the chuck (310).

[0101] Accordingly, the plurality of zones (R1, R2, R3, R4) in the chuck (310) illustrated in FIG. 13 may include a first zone (R1) that is circular, a second zone (R2) that is cross-shaped, a third zone (R3) that is triangular, and a fourth zone (R4) that is annular.

[0102] A controller included in a chucking force control device according to one embodiment of the present invention can individually control the chucking force for a plurality of zones (R1, R2, R3, R4). For example, the magnitude of the chucking force applied to the first zone may be greater than the magnitude of the chucking force applied to the fourth zone. Additionally, the magnitude of the chucking force applied to the fourth zone may be greater than the magnitude of the chucking force applied to the second zone, and the magnitude of the chucking force applied to the second zone may be greater than the magnitude of the chucking force applied to the third zone.

[0103] Accordingly, the chucking force control device can solve the overlay degradation problem by applying a low chucking force to a third zone where the overlay degradation problem is highly likely to occur, and furthermore, can improve the yield of the semiconductor device according to the process.

[0105] FIGS. 14 and 15 are drawings for explaining a fixing part included in a chucking force control device according to one embodiment of the present invention.

[0106] FIG. 14 may be a case where the chuck (310A) included in the chucking force control device according to one embodiment of the present invention is an electrostatic chuck, and FIG. 15 may be a case where the chuck (310B) included in the chucking force control device according to one embodiment of the present invention is a vacuum chuck.

[0107] Referring to FIG. 14, the electrostatic chuck (310A) can fix a substrate on the electrostatic chuck (310A) using an electrode portion comprising electrodes (E1, E2, E3, E4) corresponding to each of a plurality of zones (R1, R2, R3, R4).

[0108] A controller included in a chucking force control device according to one embodiment of the present invention can adjust the magnitude of the voltage applied to electrodes (E1, E2, E3, E4) corresponding to each of a plurality of zones (R1, R2, R3, R4) based on a reference overlay distribution. For example, similar to the chucking force applied to the plurality of zones (R1, R2, R3, R4), the controller can apply voltages from a relatively high voltage to a low voltage in the order of the first electrode (E1), the fourth electrode (E4), the second electrode (E2), and the third electrode (E3).

[0109] Referring to FIG. 15, the vacuum chuck (310B) can fix the substrate on the vacuum chuck (310B) by creating a vacuum between the substrate and the vacuum chuck (310B) using a suction part that includes a plurality of holes (H) included in each of the plurality of zones (R1, R2, R3, R4).

[0110] A controller included in a chucking force control device according to one embodiment of the present invention can adjust the suction strength through a plurality of holes (H) corresponding to each of a plurality of zones (R1, R2, R3, R4) based on a reference overlay distribution. For example, similar to the chucking force applied to the plurality of zones (R1, R2, R3, R4), the controller can adjust the suction strength through the holes (H) corresponding to the first zone (R1) to be relatively the strongest, and can adjust the suction strength in the order of the fourth zone (R4), the second zone (R2), and the third zone (R3).

[0112] FIG. 16 is a drawing for explaining the effects of a chucking force control device according to one embodiment of the present invention.

[0113] FIG. 16 may be a diagram showing the degree of overlay compensation by a chucking force control device according to one embodiment of the present invention, and may correspond to the reference overlay distribution shown in FIG. 8.

[0114] Referring to FIG. 16, a chucking force control device according to one embodiment of the present invention can solve the problem of overlay degradation that may occur on a substrate fixed to the upper surface of the chuck by dividing the chuck into a plurality of zones and controlling the chucking force individually for the plurality of zones.

[0115] For example, the first overlay compensation area (COL1) may correspond to the first overlay degradation area (OL1) shown in FIG. 8, and the second overlay compensation area (COL2) may correspond to the second overlay degradation area (OL2). In other words, the chucking force control device can perform compensation for the first and second overlay degradation areas (OL1, OL2) that may occur when a uniform chucking force is applied to the entire chuck.

[0117] FIG. 17 is a drawing for explaining a plurality of zones in a chucking force control device according to one embodiment of the present invention.

[0118] Referring to FIG. 17, a chucking force control device according to one embodiment of the present invention may divide a chuck (410) into a plurality of zones (R1, R2, R3, R4) based on a reference overlay distribution and / or a target overlay distribution. The plurality of zones (R1, R2, R3, R4) in the chuck (410) may correspond to the plurality of zones (R1, R2, R3, R4) in the chuck (310) illustrated in FIG. 13.

[0119] For example, among the multiple zones (R1, R2, R3, R4) in the chuck (410), the second zone (R2), the third zone (R3), and the fourth zone (R4) may each be identical to the second zone (R2), the third zone (R3), and the fourth zone (R4) in the chuck (310) shown in FIG. 13. However, the first zone (R1), defined as an area corresponding to the center of the chuck (410), may be smaller than the first zone (R1) in the chuck (310) shown in FIG. 13. However, this is merely one embodiment and is not limited thereto, and the size of the first zone (R1) may vary depending on the reference overlay distribution and / or the target overlay distribution.

[0121] FIG. 18 is a drawing for explaining a plurality of zones in a chucking force control device according to one embodiment of the present invention.

[0122] Referring to FIG. 18, a chucking force control device according to one embodiment of the present invention may divide a chuck (510) into a plurality of zones (R1, R2, R3, R4) based on a reference overlay distribution and / or a target overlay distribution. The plurality of zones (R1, R2, R3, R4) in the chuck (510) may correspond to the plurality of zones (R1, R2, R3, R4) in the chuck (310) illustrated in FIG. 13.

[0123] At least one of the plurality of zones (R1, R2, R3, R4) set by the chucking force control device according to one embodiment of the present invention may include a plurality of sub-zones individually controlled by a controller.

[0124] For example, in the chuck (510) of FIG. 18, the second zone (R2) may include a first sub-zone (R21) and a second sub-zone (R22) separated according to distance from the center of the chuck (510). A controller included in a chucking force control device according to one embodiment of the present invention can individually control the chucking force applied to the first sub-zone (R21) and the second sub-zone (R22).

[0125] Referring to FIG. 18, the first sub-region (R21) is depicted as concentric with the first section (R1), and the second sub-region (R22) may include a plurality of sections arranged between a plurality of third sections (R3). However, this is merely one embodiment and is not limited thereto. For example, not only the second section (R2), but also the first section (R1), the third section (R3), and the fourth section (R4) may be divided into a plurality of sub-regions in the radial and angular directions.

[0127] FIG. 19 is a drawing for explaining a plurality of zones in a chucking force control device according to an embodiment of the present invention. FIG. 20 is a drawing for explaining a plurality of zones in a chucking force control device according to an embodiment of the present invention.

[0128] Referring to FIGS. 19 and 20, a chucking force control device according to one embodiment of the present invention may divide a chuck (610, 710) into a plurality of zones (R1, R2, R3, R4) based on a reference overlay distribution and / or a target overlay distribution. The plurality of zones (R1, R2, R3, R4) in the chuck (610, 710) may correspond to the plurality of zones (R1, R2, R3, R4) in the chuck (310) shown in FIG. 13.

[0129] A chucking force control device according to one embodiment of the present invention can set a plurality of zones (R1, R2, R3, R4) to apply a small chucking force to a zone including an area with a severe degree of overlay deterioration. Accordingly, the shapes of the plurality of zones (R1, R2, R3, R4) are not limited to any one and can be set in various ways.

[0130] For example, among the plurality of zones (R1, R2, R3, R4) in the chuck (610) illustrated in FIG. 19, the third zone (R3) may be defined as having a wider range than the third zone (R3) in the chuck (310) illustrated in FIG. 13. Accordingly, the third zone (R3) may include two third zones (R3), and the second zone (R2) may have a structure that extends only in the second direction (e.g., the X direction).

[0131] Meanwhile, among the multiple zones (R1, R2, R3, R4) in the chuck (710) shown in FIG. 20, the third zone (R3) may be defined as having a wider range than the third zone (R3) in the chuck (310) shown in FIG. 13. However, the third zone (R3) in the chuck (710) may include four third zones (R3), unlike the third zone (R3) in the chuck (610) shown in FIG. 19. Meanwhile, the second zone (R2) may have a structure that extends only in the second direction, as in FIG. 19.

[0132] The setting of a plurality of zones by the chucking force control device according to one embodiment of the present invention may not be limited to those shown in FIGS. 13, 17, 18, 19, and 20. For example, the plurality of zones may be set to be separated from other zones based on detecting areas prone to degradation problems from overlay distribution measurements.

[0134] The present invention is not limited by the embodiments described above and the attached drawings, but is intended to be limited by the appended claims. Accordingly, various substitutions, modifications, and changes may be made by those skilled in the art within the scope of the technical concept of the present invention as described in the claims, and such are also to be considered to fall within the scope of the present invention. Explanation of the symbols

[0136] 1: Semiconductor process equipment 11-14, 10: Multiple process chambers 20: Transfer chamber 30: Transfer robot 40: Loadlock Chamber W: Substrate 100, 200: Chucking force control device 101, 201: Semiconductor process chamber 110, 110A, 110B, 210, 310, 310A, 310B, 410, 510, 610, 710: Chuck 120, 120A, 120B, 220: Fixed part 130, 230: Controller 240: Overlay measuring device OL1: 1st overlay degradation area OL2: 2nd overlay degradation area COL1: 1st Overlay Compensation Area COL2: 2nd Overlay Compensation Area R1: Zone 1 R2: Zone 2 R3: Zone 3 R4: Zone 4 E1: First electrode E2: Second electrode E3: Third electrode E4: Fourth electrode H: Multiple holes

Claims

Claim 1 A chuck having a substrate disposed on its upper surface; a fixing part that generates a chucking force to fix the substrate to the chuck in a first direction perpendicular to the upper surface of the chuck and applies the chucking force to the substrate; and a controller that divides the chuck into a plurality of zones according to a radial direction and an angular direction on a plane perpendicular to the first direction, based on a reference overlay distribution corresponding to the degree of overlay degradation when fixing the substrate to the upper surface of the chuck, and controls the chucking force individually for the plurality of zones; wherein the controller reduces the magnitude of the chucking force applied to a zone including an area with a large degree of overlay degradation among the plurality of zones in the reference overlay distribution, and the reference overlay distribution is determined by the anisotropy of the material constituting the substrate. Claim 2 A chucking force control device according to claim 1, wherein the chuck is an electrostatic chuck and the fixed part is an electrode part comprising electrodes corresponding to each of the plurality of zones. Claim 3 In paragraph 2, the controller is a chucking force control device that adjusts the magnitude of the voltage applied to the electrodes corresponding to each of the plurality of zones based on the reference overlay distribution. Claim 4 A chucking force control device according to claim 1, wherein the chuck is a vacuum chuck and the fixing part is a suction part including a plurality of holes for creating a vacuum between the substrate and the chuck. Claim 5 In paragraph 4, the controller is a chucking force control device that controls the suction strength through the plurality of holes corresponding to each of the plurality of zones based on the reference overlay distribution. Claim 6 A chucking force control device according to claim 1, wherein the plurality of zones include a first zone and a fourth zone positioned at different locations in the radial direction of the chuck, and a second zone and a third zone positioned at different locations in the angular direction of the chuck. Claim 7 A chucking force control device according to claim 6, wherein the first zone is defined at a position corresponding to the center of the chuck, the fourth zone is defined at a position corresponding to the outer edge of the chuck, and the first zone and the fourth zone are spaced apart from each other. Claim 8 In claim 7, the controller is a chucking force control device that controls the magnitude of the chucking force acting on the first zone to be greater than the magnitude of the chucking force applied to the fourth zone. Claim 9 In claim 6, at least one of the first to fourth zones is a chucking force control device comprising a plurality of sub-zones individually controlled by the controller. Claim 10 A chucking force control device according to claim 6, wherein the second zone extends in a second direction perpendicular to the first direction and in a third direction perpendicular to the first direction and the second direction with respect to the center of the chuck, and the third zone comprises a plurality of third zones disposed between the second zone and the fourth zone in a direction parallel to the upper surface of the chuck. Claim 11 In claim 10, the controller is a chucking force control device that controls the magnitude of the chucking force acting on the second zone to be greater than the magnitude of the chucking force acting on the third zone. Claim 12 In claim 10, the controller is a chucking force control device that controls the magnitude of the chucking force acting on the first zone and the fourth zone to be greater than the magnitude of the chucking force acting on the second zone and the third zone. Claim 13 A chucking force control device according to claim 6, wherein among the plurality of zones, the first zone is circular, the second zone is cross-shaped, the third zone is triangular, and the fourth zone is annular. Claim 14 A chucking force control device further comprising, in claim 1, an overlay distribution measuring device that measures the degree of overlay degradation of the substrate and transmits the measurement result to a controller. Claim 15 In claim 14, the controller sets a new plurality of zones based on a target overlay distribution corresponding to the measurement result, and the chucking force control device controls the chucking force individually for the new plurality of zones. Claim 16 A chuck having a substrate disposed on its upper surface; a fixing part that generates a chucking force to fix the substrate to the chuck and applies the chucking force to the substrate; and a controller that divides the chuck into a plurality of zones according to a radial direction and an angular direction, wherein the plurality of zones include at least one vulnerable zone that is relatively likely to cause overlay degradation problems due to relatively low rigidity and low restoring force, and controls the chucking force individually for the plurality of zones. A chucking force control device comprising, wherein the plurality of zones include a first zone defined at a position corresponding to the center of the chuck, a second zone and a third zone defined at a position corresponding to the outside of the first zone, and a fourth zone defined at a position corresponding to the outer edge of the chuck, wherein the second zone and the third zone are disposed between the first zone and the fourth zone, and the magnitude of the chucking force applied to the second zone and the third zone is controlled to be smaller than the magnitude of the chucking force applied to the first zone and the fourth zone, and the magnitude of the chucking force applied to the second zone is controlled to be larger than the magnitude of the chucking force applied to the third zone, which is the weak zone, and the first to fourth zones are distinguished based on a reference overlay distribution determined by the anisotropy of the material constituting the substrate. Claim 17 A chucking force control device according to claim 16, wherein at least one of the second zone and the third zone is disposed between the first zone and the fourth zone in at least one of the directions parallel to the upper surface of the chuck. Claim 18 A chucking force control device according to claim 16, wherein at least three of the first to fourth zones are arranged in at least one of the directions parallel to the upper surface of the chuck. Claim 19 A chucking force control method comprising: a step of measuring a reference overlay distribution corresponding to the degree of overlay degradation when fixing a substrate to the upper surface of a chuck; a step of dividing the chuck into a plurality of zones according to a radial direction and an angular direction based on the reference overlay distribution; a step of individually controlling a chucking force for the plurality of zones; and a step of fixing the substrate to the chuck using the chucking force; wherein the reference overlay distribution is determined by the anisotropy of the material constituting the substrate, and the plurality of zones include at least one vulnerable zone that is relatively likely to have an overlay degradation problem due to relatively low stiffness and low restoring force, and the magnitude of the chucking force applied to the vulnerable zone is relatively small. Claim 20 A chucking force control method according to claim 19, further comprising: a step of measuring a target overlay distribution corresponding to the degree of overlay degradation during the process; a step of resetting the plurality of zones in the chuck based on the target overlay distribution; and a step of individually controlling the chucking force for the reset plurality of zones.

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