TWI595532B - Spin coating apparatus and method for manufacturing semiconductor device - Google Patents

Description

Rotary coating apparatus and method for manufacturing the same

The techniques disclosed herein relate to spin coating systems and procedures that include spin coating of a semiconductor substrate.

Spin coating has been used for decades as a method of coating flat surfaces with thin layers of polymers, photoresists, or other compounds. Spin coating is typically carried out by depositing a solvent solution, polymer solution, or other liquid material onto a flat substrate. The substrate is then rotated at an angular velocity sufficient to generate a centrifugal force that causes the solution to flow outward toward the edge of the substrate, thereby coating the entire surface of the substrate. Excess solution will be ejected from the edge of the substrate, while the remaining solution becomes thinner and hardens as the solvent evaporates, leaving a thin polymer film.

A routine step in lithography used in the manufacture of such spin coating semiconductor elements. In an exemplary lithography process, a resist spin coating step is performed to form a uniform resist film on a semiconductor wafer. Next, the exposure process typically involves exposing the resist film to light or other radiation via a reticle that produces a potential line pattern. Finally, the developing step includes developing the resist coated wafer after the exposure process to reveal a line pattern. This series of processing stages is typically carried out in a coating-developing system.

In a typical spin coating process, a semiconductor wafer or other substrate is rotated with the rotating chuck by a rotary drive mechanism. The wafer can be vacuumed (or otherwise secured) Hold on the rotating chuck. A resist nozzle disposed over the semiconductor wafer drops the resist solution onto the center of the wafer surface. As the wafer rotates, the dripped resist solution diffuses radially outward toward the circumference of the semiconductor wafer by centrifugal force. Although the diffusion of the resist occurs relatively quickly throughout the surface of the wafer, the semiconductor wafer continues to rotate (typically at a reduced rotational speed) for a period of time to spin the resist solution scattered over the surface of the wafer. And dry. Such spin coating has been widely used in the semiconductor industry and is mainly used to form a thin, uniform photoresist polymer layer on the surface of the wafer as a preliminary step for further wafer processing.

A common expectation in semiconductor manufacturing and spin coating is high throughput. During semiconductor fabrication, the wafer can be subjected to multiple coating and development steps. Therefore, minimizing the program time for completing each spin coating of the wafer can increase the throughput. In other words, it is desirable to complete the spin coating or rotation process in as little time as possible to increase the number of wafers that can be processed per unit time. Along with the challenge of increasing production capacity, the requirements for uniformity and quality are met. In a typical spin coating process that uses rotation to spread liquid material throughout the wafer and dry the liquid material, the drying time is substantially longer than the diffusion time. There are various techniques that can be used to speed up drying time. A basic technique is to increase the rotational speed of the wafer, which in turn increases the velocity of the fluid flowing across the surface of the wafer - the faster the wafer rotates, the more the liquid resist or other liquid chemical dries (solvent evaporation) fast.

However, higher substrate rotational speeds can result in non-uniformities and/or defects in the coating. These defects are typically the result of turbulent air flow across the surface of the wafer caused by relatively fast rotational speed. A particular problem with the higher rotational speed of the substrate is the development of wind marks, also known as Ekman spirals. This is a phenomenon that occurs when the wafer is rotated at ever higher angular velocities until the fluid flow (air and solvent) above the wafer changes from laminar to turbulent. Just before complete turbulence occurs, there is a strong secondary flow leading to a spiral pattern on the surface of the photoresist. Due to the lack of uniformity of resist thickness, these patterns (wind marks) can cause defects during subsequent processing steps.

For a particular substrate diameter, there is a maximum speed at which a wafer can rotate before the air flow exceeds a critical value and begins to form a wind mark in the resist. The critical value for the formation of wind marks is based on a combination of diameter and angular velocity. The origin of the wind mark is related to the value of the specific Reynolds number. The Reynolds number for spin coating uses the air density above the wafer, the angular velocity of the wafer, the radial position from the center of the wafer, and the viscosity of the air to quantify the inertial force and the viscous force. The critical Reynolds number shows the point at which instability occurs. Due to wind marks, the critical Reynolds number limits the angular velocity based on the edge radius of a particular wafer W. As the diameter of the substrate increases, the maximum angular velocity needs to be reduced because the tangential velocity at the radial distance further from the axis of rotation increases. In other words, when rotating a larger disc, it is necessary to reduce the rotational speed to prevent wind marks near the edges of the wafer.

This is especially challenging when the semiconductor industry is converting from processing wafers with a diameter of 300 mm to processing wafers with a diameter of 450 mm. For example, some conventional spin coating systems for coating 300 mm wafers can rotate wafers up to about 1800 revolutions per minute (rpm), where liquid is distributed and diffused in seconds, and The solvent evaporates completely in less than about one minute (depending on the chemical). However, when the substrate diameter is increased to 450 mm, the rotational speed needs to be reduced to about 900 rpm to avoid wind marks. This reduction in speed has two major challenges. One challenge is that at such relatively low rotational speeds, the liquid does not spread evenly across the wafer surface (lower centrifugal force). Another challenge with lower rotational speed is a significant increase in drying time. At lower rotational speeds, solvent evaporation can take up to three or four minutes or more, which means that the production time per unit wafer surface area is actually reduced, even though the 450mm wafer is double the area of the 300mm wafer. Still big.

The techniques disclosed herein provide apparatus and methods for spin coating that inhibit the formation of wind marks and other defects from turbulent fluid flow, thereby achieving higher rotational speeds and reduced drying times while maintaining film uniformity. . The techniques disclosed herein include fluid flow members, such as a cover or ring, that are placed or suspended above the substrate support or over the top surface of the wafer or other substrate. The fluid flow member has a radial curvature that prevents wind marks during rotation of the wafer or other substrate.

One embodiment includes a spin coating apparatus having a substrate holder configured to hold a substrate horizontally during a spin coating process, such as by using a vacuum chuck. A rotating mechanism (such as a motor) is coupled to the substrate holder. The rotating mechanism is configured to rotate the substrate holder about a rotational axis. The apparatus includes a liquid dispenser configured to dispense liquid material onto a work surface of the substrate when the substrate is disposed on the substrate support. The working surface is substantially planar and is located opposite the bottom surface of the substrate that contacts the substrate support. The apparatus includes a fluid flow member having a surface of a face substrate. The fluid flow member is configured to be positioned such that when the substrate is disposed on the substrate support, the surface of the surface substrate is vertically above the working surface of the substrate. At least a portion of the surface of the face substrate is curved such that a particular vertical distance between the surface of the face substrate and the work surface varies radially relative to a particular radial distance from the axis of rotation. In other words, although the working surface of the substrate is substantially planar, the fluid flow members suspended above are curved, and thus, the particular height of the surface of the surface substrate above the working surface depends on the particular radius of the substrate.

Another embodiment includes a method for fabricating a semiconductor component. This method has a number of steps including placing the substrate on a substrate support. The substrate holder holds the substrate horizontally and has a rotating shaft. The substrate has a bottom surface that contacts the substrate holder and a working surface that faces the bottom surface. In another step, the fluid flow member is disposed above the substrate support. The fluid flow member has a face substrate surface disposed at a predetermined average vertical distance vertically above the work surface or at an average height above the work surface. At least a portion of the surface of the surface of the substrate is curved, so that The particular vertical distance between the surface of the face substrate and the work surface varies radially relative to a particular radial distance from the axis of rotation. The liquid material is dispensed onto the working surface of the substrate through a liquid dispenser located above the substrate. The substrate and the substrate holder are rotated together by a rotating mechanism coupled to the substrate holder, so that the liquid material is diffused throughout the working surface of the substrate and then dried by the rotating action.

Of course, the order of discussion of the different steps as described herein has been shown for purposes of clarity. In general, these steps can be performed in any suitable order. Accordingly, although various features, techniques, configurations, etc., may be discussed in various places in the disclosure, it is intended that each of the concepts can be performed independently or in combination with each other. Thus, the invention can be embodied and appreciated in many different ways.

It should be noted that the section of the present disclosure does not specifically describe each embodiment and/or progressive novel embodiments of the present disclosure or the claimed invention. Instead, the present disclosure provides only a preliminary discussion of corresponding novel features and different embodiments with respect to the prior art. For additional details and/or possible aspects of the present invention and the embodiments, the reader is directed to the embodiments of the disclosure and the corresponding drawings, as discussed further below.

100‧‧‧Resist Coating Unit (COT)

102‧‧‧Substrate support (rotary chuck)

103‧‧‧Drive motor

109‧‧‧ holding components

110‧‧‧resist nozzle

111‧‧‧Resist feed tube

112‧‧‧Resist nozzle scanning arm

113‧‧‧Nozzle bracket

114‧‧‧rail

115‧‧‧Vertical support members

121‧‧‧ (outside) edge

125‧‧‧Working surface

127‧‧‧radial distance

141‧‧ ‧ dust filter

142‧‧‧ Humidity controller

150‧‧‧ Fluid flow components

150-1‧‧‧Outer ring

150-2‧‧‧ Inner ring

155‧‧‧ surface of the substrate

157‧‧‧ openings

162‧‧‧Circular substrate

164‧‧‧ leaves

165‧‧‧slit

166‧‧‧ rods

167‧‧‧fasteners

168‧‧‧Installation ring

180‧‧‧Rotary axis

CP‧‧‧(round) cups

W‧‧‧ wafer

X, Y‧‧ direction

A more complete understanding of the various embodiments of the present invention, together with the The drawings are not necessarily to scale, the &quot

Figure 1 is a cross-sectional view showing the schematic structure of a spin coating apparatus.

2 is a top plan view of the spin coating apparatus of FIG. 1.

3 is an enlarged cross-sectional view of a fluid flow member in accordance with an embodiment herein.

4 is an enlarged cross-sectional view of a fluid flow member in accordance with an embodiment herein.

Figure 5 is a cross-sectional view of an alternate embodiment of a fluid flow member as described herein.

6A-6C are top views of alternative embodiments of fluid flow components as described herein.

Figure 7 is a top plan view of an alternate embodiment of a fluid flow member as described herein.

8A-8B are top views of alternative embodiments of fluid flow components as described herein.

9 is a top plan view of an alternate embodiment of a fluid flow member having an adjustable opening as described herein.

Figure 10 is a side elevational view of an alternate embodiment of a fluid flow member having an adjustable opening as described herein.

11 is an exploded perspective view of an alternate embodiment of a fluid flow member having an adjustable opening as described herein.

The description below sets forth certain details, such as the specific geometry of the processing system, the various elements and procedures used therein, for purposes of illustration and not limitation. However, it is to be understood that the invention may be embodied in other embodiments without departing from the specific details.

Similarly, the specific quantities, materials, and configurations are set forth to provide a comprehensive understanding of the invention. Nevertheless, the invention may be practiced without specific details. In addition, it is understood that the various embodiments shown in the drawings are illustrative and not necessarily to scale.

Various operations will be described as multiple independent operations in a manner that best aids in understanding the invention. However, the order of description should not be construed as to imply that the operations must be in the order. In particular, these operations need not be performed in the order indicated. The described operations can be performed with the implementation The examples are executed in different orders. In additional embodiments, various additional operations may be performed, and/or the operations described may be omitted.

In accordance with the present invention, "substrate" as used herein generally refers to a treated article. The substrate may comprise any material portion or structure of an element, in particular a semiconductor or other electronic component, and may for example be a base substrate structure, such as a semiconductor wafer, or a layer on or over the base substrate structure, for example film. Thus, the substrate is not intended to be limited to any particular substrate structure, underlying layer or cover layer, patterned or unpatterned, but is contemplated to include any such layer or substrate structure, as well as layer and/or substrate structure. Any combination. The following description may refer to a particular substrate type, but this is for illustrative purposes only and not limiting.

Accordingly, the techniques disclosed herein provide apparatus and methods for spin coating that inhibit the formation of wind marks and other defects caused by turbulent fluid flow, thereby achieving higher rotational speeds and reduced drying times. At the same time, the uniformity of the film is also maintained. The techniques disclosed herein include fluid flow members, such as covers, rings, or other air flow structures that are disposed or suspended above the substrate support or over a substrate disposed on the substrate support. The fluid flow member has a radial curvature that is selected to prevent wind marks and other effects of turbulent air flow during rotation of the wafer or other substrate. The fluid flow member is disposed adjacent to the substrate. The shape, size, and location of the fluid flow member help maintain fluid flow (usually solvent and air) over the surface of the wafer coated with the liquid material and accelerate drying time while maintaining the thickness and coverage of the coating. Aspect uniformity.

The exemplary embodiments will be described with reference to the drawings. For convenience, the embodiments herein will be described in the context of using a resist as part of semiconductor fabrication. However, it should be noted that other liquid materials may also be used for spin coating of semiconductor wafers, or any other substantially planar substrate. 1 is a cross-sectional view showing a schematic configuration of a resist coating unit (COT) 100 (rotary coating apparatus). 2 is a cross-sectional top plan view showing the general structure of a resist coating unit (COT) 100, in accordance with an embodiment of the present invention.

A circular cup (CP) is disposed in the center of the resist coating unit 100. The substrate holder 102 (spinning chuck) is disposed in the cup CP, and when the waste fluid flows out of the edge of the substrate, the cup CP receives the waste fluid and flows down to the draining device. When a substrate such as a semiconductor wafer (hereinafter referred to as "wafer") W is vacuum-adsorbed on the substrate holder 102, the substrate holder 102 is rotated by a rotating mechanism (for example, the drive motor 103). Other substrate holding mechanisms can also be used. The drive motor 103 can be disposed in an opening in the CP and can selectively include a lift mechanism that moves the substrate support 102 up and down. The lifting mechanism can be, for example, an air cylinder and includes upward and downward guiding units. The motor can include a cooling unit and is constructed of materials that are advantageous for the spin coating process.

The wafer W can be transferred to the substrate holder 102 by the holding member 109 as a part of a wafer transfer mechanism (not shown). The up and down drive units can raise the drive motor 103 and/or the substrate support 102 to receive the wafer W. Alternatively, the cup CP can be moved up or down and separated and widened to allow the wafer W to be placed on the substrate support 102.

The liquid dispenser includes a resist nozzle 110 for supplying a resist solution onto the surface of the wafer W, and is connected to the resist supply through the resist feed tube 111. The resist nozzle 110 is detachably attached to the front end of the resist nozzle scanning arm 112 through the nozzle holder 113. The resist nozzle scanning arm 112 is attached to the upper end portion of the vertical support member 115, and the vertical support member 115 is horizontally movable in one direction (Y direction) on the guide rail 114. The resist nozzle scanning arm 112 is thus moved in the Y direction together with the vertical support member 115 by a Y-direction driving mechanism (not shown). Other mechanisms can be used to move the resist nozzle 110 in the Z-direction and/or the X-direction. The resist nozzle 110 can be interchanged with other different types or sizes of resist nozzles. The solvent atmosphere can be used to prevent curing or degradation of the resist solution at the front end of the nozzle.

Coating of the resist may include applying a solvent to act as a diluent to wet the surface of the wafer prior to supplying the resist solution to the surface of the wafer. This initial solvent can be resisted by The agent nozzle 110 or an adjacent nozzle is coated. The solvent and resist can be supplied via one or more adjacent feed tubes (not shown), and one or more scanning arm assemblies.

A high efficiency dust collecting filter 141 is disposed above the wafer W. Temperature and Humidity The air conditioned by the temperature and humidity controller 142 passes through the high efficiency dust collecting filter 141 to remove dust, thereby supplying clean air to the resist coating unit (COT) 100. It should be noted that a gas containing a solvent such as a resist solution may be introduced instead of air.

A control system or controller (not shown) of the resist coating unit (COT) 100 can be used to control and manage various spin coating operations. The controller can include a program controller having a CPU, a user interface, and a memory unit. The user interface is coupled to the program controller and includes input means for allowing the program manager to perform a command input operation or the like to control the resist coating unit 100, for example via displaying a resist coating unit A display that visualizes the operational status of 100. The memory unit connected to the program controller stores: a control program (software) for implementing various programs to be executed by the resist coating unit (COT) 100 controlled by the program controller; Program condition data or a recipe for multiple parts of the similarity.

When a particular recipe is commanded to be called, or for example, via a user interface, the resist coating unit (COT) 100 performs the required program under the control of the program controller. The controller controls the driving of, for example, the drive motor 103, the resist supply, and the solvent supply. Specifically, the controller controls the drive motor 103 to increase or decrease its rotational speed. The controller also controls the timing of supplying the resist solution from the resist supply to the resist nozzle 110, the timing of supplying the solvent such as the diluent from the solvent supply to the solvent nozzle, and the solvent to be supplied and The amount and type of resist solution.

The recipe and control program of the program condition data may be those stored in a computer readable memory medium (such as a CD-ROM, a hard disk, a floppy disk, or a flash memory), or may be from another device via a dedicated line. Delivered online for your needs.

The resist coating unit 100 also includes a fluid flow member 150. In the embodiment of Figures 1 and 2, the fluid flow member 150 is shown as a member that is integrated with the cup CP into a relatively thin structure. However, this integration is only an exemplary embodiment. In other embodiments, the fluid flow member 150 can be attached to an upper structural member within the resist coating unit 100, such as to the resist nozzle scanning arm 112. In the embodiment when attached to the scanning arm, when the wafer W is placed on or removed by the substrate holder 102, the fluid flow member 150 can be moved to the side. In another embodiment, the fluid flow member can be mounted adjacent to the cup CP and can include an independent vertical motion mechanism.

In general, the fluid flow member 150 provides a face substrate surface 155 with at least a portion of which is curved in a radial direction relative to the axis of rotation 180 of the substrate support 102. This can result in a curved plate or ring located above the wafer W (substrate) when the wafer W is disposed on the substrate support 102. The curvature is such that the fluid flow member 150 is closer to the wafer W at the outer edge 121 of the wafer W than at a radial distance closer to the axis of rotation. Further, the vertical distance or height between the fluid flow member 150 and the wafer W increases as the rotation axis 180 moves.

In certain embodiments, such as in FIG. 5, the fluid flow member 150 can maintain a curvature and extend to the axis of rotation 180, thereby causing the fluid flow member to have a conical shape. In other embodiments, such as in FIG. 2, fluid flow member 150 can define an opening 157 above wafer W to receive resist and air. This would allow for better control of wind mark formation at the edge of the wafer while allowing more air to flow into or through the center or opening 157.

Referring now to Figure 3, such a curved member above the substrate (wafer) will increase the laminar flow of solvent and air over the coated substrate, but in the event that the fluid flow member begins to cover the substrate, Bumps are created in the resist (as can be seen in the case of having a completely flat annular cover, or a curvature that is too large or too small). Such bumps are formed by an increase in local film thickness caused by enhanced evaporation. The curvature of the fluid flow member provides a stepwise transition from the substantially curved inner annular portion 150-2 to the generally linearly inclined or straight outer annular portion 150-1.

Techniques for using such fluid flow components can include procedures for moving the fluid flow components up and down to prevent defects. For example, fluid flow member 150 can be made to reduce turbulence at an optimum height relative to the wafer, but bringing the fluid flow members so close during the liquid material (resist) diffusion phase can result in defects. When the liquid material is initially dispensed onto the substrate, there will be some splatter as the liquid diffuses to the edge of the substrate. If the particles splatter and land on the fluid flow member (initially too close to the wafer), the particles then fall back onto the substrate and create defects. During initial dispensing of the liquid material, the fluid flow member can avoid any possible splashes by initially maintaining the fluid flow member at a position high above the wafer W, and then after the time period of particle blast has been completed , reduce to the optimal height. Next, the wafer W can continue to spin dry the liquid material while the fluid flow member promotes laminar flow of fluid over the surface of the liquid material on the wafer W. As a result, wind marks in the surface of the resist are prevented, thereby maintaining uniformity in the layer formed on the wafer.

Some exemplary embodiments are now discussed. One embodiment includes a spin coating apparatus for coating a substrate, such as wafer W, although other substrates such as liquid crystal display (LCD) substrates can be used. The apparatus includes a substrate holder configured to horizontally hold the substrate during a spin coating process. Vacuum suction is a typical mechanism for holding, but the use of notches to receive the clamping of the substrate, or other holding mechanisms can be used. The rotating mechanism is coupled to the substrate support. The rotating mechanism is configured to rotate the substrate holder about the axis of rotation while simultaneously rotating the substrate on the substrate holder. The apparatus includes a liquid dispenser configured to dispense a liquid material (e.g., a resist) onto a work surface of the substrate when the substrate is disposed on the substrate support. FIG. 3 shows an exemplary work surface 125. The working surface is planar and opposite the bottom surface of the substrate, where the bottom surface is in contact with the substrate support. In other words, the working surface is a top surface corresponding to the substrate holder that holds the substrate horizontally.

The apparatus includes a fluid flow member having a face substrate surface 155. The fluid flow member is configured to be disposed or suspended. When the substrate is disposed on the substrate holder, the surface of the surface substrate is disposed on the base The working surface of the board is vertically above. At least a portion of the surface of the face substrate is curved such that a particular vertical distance between the surface of the face substrate and the work surface varies radially relative to a particular radial distance from the axis of rotation. In other words, the fluid flow member has a curvature that varies from the edge 121 toward the center of the substrate (which coincides with the axis of rotation 180).

In some embodiments, a particular vertical distance between the surface of the face substrate and the work surface can be varied such that the particular vertical distance decreases as the radial distance from the axis of rotation increases. In other words, the higher the center fluid flow member toward the substrate, the lower the fluid flow member at the edge of the substrate. When the working surface has a circular shape, the surface of the face substrate may be located above the annular portion of the work surface. The annular portion extends from the outer edge of the working surface to a predetermined radial distance from the axis of rotation. The fluid flow member can define a circular opening vertically above the circular portion of the working surface that extends from the axis of rotation to a predetermined radial distance. Thus, the fluid flow member is suspended above the peripheral portion of the substrate, while the central opening allows air flow from above (e.g., from the dust collection filter 141).

In another embodiment, the surface of the face substrate has an outer annular portion (eg, portion 150-1) and an inner annular portion (eg, portion 150-2). The inner annular portion is closer to the rotating shaft 180 than the outer annular portion. The inner annular portion of the surface of the face substrate is radially curved, and the outer annular portion of the surface of the face substrate has a nearly linear radial slope. Thus, the distinctly curved portion of the fluid flow member is closer to the center of the substrate, and above the edge portion of the substrate, the fluid flow member is substantially flat, which may include making the radius substantially larger to appear nearly linear.

In an alternative embodiment, the inner annular portion of the surface of the face substrate is radially curved, and the outer annular portion of the surface of the face substrate is flat so that when the fluid flow member is positioned vertically above the working surface of the substrate, There is a substantially fixed vertical distance between the working surface and the outer annular portion of the surface of the facing substrate. In other words, the inner annular portion of the fluid flow member is curved and the outer annular portion has a fixed height above the substrate.

Embodiments can include a vertical motion mechanism configured to increase or decrease the average vertical distance between the face substrate surface 155 and the work surface 125 when the substrate is disposed on the substrate support. Since the surface of the face substrate is at least partially curved, there can be a variable height at any particular radial distance (but at the same specific radial distance around the fluid flow member, the same height). Therefore, the average vertical distance can be used to confirm the vertical motion/position of the fluid flow member above the surface of the face substrate, that is, the average suspension distance. The vertical motion mechanism can be configured to set the vertical distance between the outer annular portion and the working surface to less than about 5 millimeters or less than about 10 millimeters. Suspending the outer annular portion at about 10 mm can increase laminar flow compared to uncovered, leaving the vertical distance between the outer annular portion and the working surface less than about 5 mm or even less than about 3 or 4 mm. A significantly better laminar flow will result. The inner annular portion of the surface of the face substrate can have a first radius of curvature of between about 20 mm and 90 mm.

In an alternate embodiment, the surface of the face substrate is maintained at a predetermined average vertical distance above the work surface for a first period of time prior to dispensing the liquid material onto the work surface. This can be the initial height selected to avoid particles being spattered onto the surface of the face substrate. The first period of time may be relatively short compared to the total substrate rotation time. For example, the first time period can be from a fraction of a second to one or a few seconds. After the beginning of dispensing the liquid material, the predetermined average vertical distance is reduced to a second predetermined average vertical distance by the vertical motion mechanism during the second time period. This second time period can be relatively longer than the first time period. By way of non-limiting example, the second time period can be 5 seconds, 10 seconds, 15 seconds or longer. During this second period of time, the rotational speed of the substrate can be increased. Also, the second predetermined average vertical distance may be relatively close to the substrate such that the shortest vertical distance is about 2 mm. Next, the predetermined average vertical distance is increased to a third predetermined average vertical distance during the third time period while the substrate is held to rotate on the substrate support. This third period of time may be substantially longer than the second period of time, such as two or three or more times longer. The third predetermined average vertical distance can also have a shortest distance to the substrate, for example about 10 or 15 mm. As the surface of the surface substrate is raised higher above the substrate, A corresponding decrease in the rotational speed of the substrate may be performed to maintain the flow below the turbulence threshold. Rotation during this third period of time can continue until drying is complete, or until the wafer can be moved to the hot plate. Thus, the top plate or cover member can be lowered at a point in time to avoid splashing, but early enough to avoid turbulence effects, and the top plate or cover member can be raised to help maintain film uniformity. It should be noted that the times and distances given herein are exemplary, and the actual time period, rotational speed, and distance may depend on the particular chemical and/or formulation steps used.

In another embodiment, the surface of the face substrate has an outer annular portion and an inner annular portion. The inner annular portion is closer to the rotation axis than the outer annular portion. The inner annular portion of the surface of the face substrate has a first radius of curvature, and the outer annular portion of the surface of the face substrate has a second radius of curvature. The second radius of curvature is different from the first radius of curvature. The surface of the face substrate is convex relative to the work surface, as shown in FIG. The first radius of curvature may be between about 20 mm and 90 mm, and the second radius of curvature may be between about 1000 mm and 2000 mm. Alternatively, the first radius of curvature may be between about 50 mm and 70 mm, and the second radius of curvature may be between about 1300 mm and 1500 mm.

In some embodiments, the face substrate surface defines a frustoconical shape that is convex relative to the work surface such that the distance between the face substrate surface and the work surface decreases in a radial direction toward the outer edge of the work surface. . Although the surface of the face substrate is curved, the fluid flow member itself may be relatively flat, such as a panel, or may be a block having a greater thickness. The face substrate surface can have a curvature selected to improve drying uniformity during the spin coating process, i.e., a shape of a particular curvature can be selected to improve drying uniformity when the substrate is spin dried. The particular vertical distance that varies between the surface of the face substrate and the work surface can be selected to minimize turbulent fluid flow over the work surface. It should be noted that if the height is relatively large (for example, more than 10 cm), there may be little benefit. Similarly, if the height is too small (eg, may be less than 1 mm), there may be some turbulence and/or a decrease in uniformity. Therefore, the curvature is optimized for uniformity, while the height is selected to balance uniformity and turbulence.

4 shows an enlarged cross-sectional view of an exemplary fluid flow member similar to that of FIG. It should be noted that while the fluid flow member of Figure 4 has an approximate radial curvature, the cross-section shows that the face substrate surface 155 is comprised of a plurality of planar (linear) segments. Thus, the surface of the face fluid of the fluid flow member can be comprised of a plurality of planar radial segments that have a cross-sectional curvature of the plurality of linear segments, such as those that can be considered as surface portions of surface substrate 155. By.

In other embodiments, the face substrate surface can be configured to rotate with the substrate support, as shown in FIG. Depending on the particular material and program conditions, the benefits of uniformity and fluid flow can be obtained with the fluid flow member rotating with the substrate.

Figure 6 is a top plan view of various configurations of fluid flow members. In these embodiments, the fluid flow member defines an opening that causes the fluid flow member to form a partial loop above the substrate support. By way of a non-limiting embodiment, Figure 6A shows a fluid flow member defining an angular opening. Figure 6B shows a substantially semicircular fluid flow member. Fig. 6C shows another exemplary opening in which the line edges of the openings are substantially perpendicular to each other.

Figure 7 shows a top view of a separate fluid flow member or top plate. In this embodiment, the fluid flow component is comprised of a plurality of sections that are mechanically movable (either vertically or laterally) from the substrate support. Such movement can help to place and retrieve the substrate on the substrate support and allow the nozzle arm to move. In one embodiment, portions of the fluid flow member can be attached to the movable arm such that no portion of the fluid flow member can cover the wafer. Each arm can move with the other arms to form a continuous fluid flow member. It is also possible to move the parts apart by a relatively small distance to better optimize the balance between thickness uniformity and turbulence control. Thus, an embodiment includes a fluid flow member having two or more segments (eg, four segments) configured to move at least one of the segments to move away from adjacent segments. It should be noted that such segments may have a radial curvature as previously described, or may be a substantially planar segment that forms a substantially planar surface of the substrate.

Figures 8-11 show a diagram of a fluid flow member having a dynamically changing central opening. Figures 8A and 8B show top views of fluid flow members having openings of a particular diameter, and this particular diameter is increased to reduce the overall surface area of the fluid flow members. Figure 9 is a top plan view of an exemplary embodiment of such a fluid flow member defining a nearly circular opening centered on the axis of rotation of the substrate support/wafer, and Figure 10 is the display side view. The fluid flow component is configured to increase and/or decrease the diameter of the defined opening. The illustrated example essentially embodies this technique as a diaphragm or shutter opening.

The fluid flow member can include a diaphragm member and an annular substrate 162. The diaphragm member can include several components, such as vanes 164 and rods 166. The rod 166 can pass through the slit 165 of the blade 164 and hold the blade by a fastener 167. The rod 166 can also be attached to the mounting ring 168. Movement of the mounting ring 168 by rotating the mounting ring causes the blade to increase and/or decrease the diameter of the defined opening. As the mounting ring 168 rotates, the bars 166 can move past the slits 165, thereby causing the blades 164 to reposition themselves, such as sliding past each other. This in turn increases or decreases the defined opening. Thus, in this embodiment, the fluid flow member can be considered to have a ring with an adjustable inner radius or diameter. With this adjustability, fluid flow components can be dynamically adjusted for specific applications.

Other embodiments may include methods for fabricating semiconductor components, where the method includes several steps. The substrate is disposed on the substrate support, such as by using a robotic arm. The substrate holder holds the substrate horizontally. The substrate holder has a rotating shaft. The substrate has a bottom surface that is in contact with the substrate support and has a working surface opposite the bottom surface. The fluid flow member is disposed above the substrate support. The fluid flow member has a surface of the planar substrate, and the step of providing the fluid flow member includes positioning the surface of the surface substrate at a predetermined average vertical distance vertically above the working surface. At least a portion of the surface of the face substrate is curved such that a particular vertical distance between the surface of the face substrate and the work surface varies radially relative to a particular radial distance from the axis of rotation. A liquid material, such as a resist, is dispensed onto the working surface of the substrate by a liquid dispenser located above the substrate. Then coupled to the substrate The rotating mechanism of the seat rotates the substrate and the substrate holder to spread the liquid material throughout the working surface of the substrate.

In another embodiment, the surface of the face substrate is maintained at a predetermined average vertical distance above the work surface prior to dispensing the liquid material onto the work surface, and after the liquid material is initially dispensed, the predetermined average vertical is made through the vertical motion mechanism. The distance is reduced to a second predetermined average vertical distance. The surface of the surface substrate has an outer annular portion and an inner annular portion, and the inner annular portion is closer to the rotation axis than the outer annular portion. The inner annular portion of the surface of the face substrate is radially curved, and the outer annular portion of the surface of the face substrate has a nearly linear radial slope such that the step of reducing the predetermined average vertical distance to a second predetermined average vertical distance results in a face substrate The outer annulus of the surface is located less than about 4 mm from the working surface. When the working surface has a diameter of about 300 mm, the outer annular portion extends beyond a radial distance 127 of about 80-120 mm from the axis of rotation. When the working surface has a diameter of about 450 mm, the outer annulus extends beyond a radial distance 127 of about 100-170 mm from the axis of rotation.

It should be noted that in the case of fluid flow members, there are several variables that can affect the maximum angular velocity. For example, optimized pressure can help promote laminar flow. In the case of a low pressure, the reflux conditions can develop to cause turbulence. Other variables include the type of substrate and the type of liquid material. Although circular or disk-shaped and rotating devices are not required to act on rectangular and other shaped substrates, they are generally circular or disk-shaped for wafers. There are many different types of resists and solvents to choose from. Each solvent can have its own flow rate and evaporation characteristics. Therefore, it should be understood that the fluid flow member, average height, and rotational speed can be adjusted based on substrate and resist characteristics to produce optimum drying time and film uniformity. For example, for a resist commonly used in semiconductor fabrication on a wafer, it is advantageous to have a relatively large outer diameter portion having a vertical distance of less than about 3 mm (between the working surface and the surface of the surface substrate). of. By way of non-limiting example, when processing a wafer having a radius of 150 mm, the vertical distance other than about 110 mm (about 165 mm for a wafer having a radius of 225 mm) is set to less than about 3 mm and even gradually cut back To about 1.5 mm results in a significantly improved laminar flow at higher rotational speeds (e.g., up to 2800 rpm or more).

Other embodiments include reducing the first predetermined average vertical distance to a second predetermined average vertical distance for a predetermined time from the beginning of dispensing the liquid material onto the work surface. By way of non-limiting example, the resist is deposited on the substrate, the substrate is rotated, and after about one second the resist covers the substrate, allowing the surface of the planar substrate to be lowered during spin drying to promote laminar fluid flow. Also, in another embodiment, the surface of the face substrate can be rotated in the same direction of rotation as the substrate holder, so that the surface of the face substrate is rotated at about the same angular velocity as the working surface.

Other embodiments include methods for varying cup venting in different formulation steps to optimize the balance between film thickness uniformity and particle generation while maintaining turbulence control. When a top plate (fluid flow member) is used, having a relatively low exhaust rate generally has a good film thickness uniformity, i.e., a relatively low exhaust rate results in a more uniform film thickness. However, one conflict of interest is that having a lower exhaust rate than a particular value can cause particles to land on the wafer being processed. This risk is higher with specific procedural steps, and thus the method can include increasing venting during specific process steps that have a higher probability of being contaminated by particulates. In addition, if the exhaust is too low, pressure may build up in the spin coating module and spread the particles into other parts of the wafer fabrication system. Therefore, higher exhaust rates typically result in fewer defects, while lower exhaust rates generally result in better uniformity. Thus, the technique can include using a fluid flow member in combination to adjust the exhaust rate to maintain the defect below a predetermined amount and to maintain uniformity above a predetermined value.

Depending on the process conditions and the nature of the liquid material, the fluid flow components and methods herein can improve uniformity to varying degrees. For example, depending on the specific choice of pressure, temperature, and type of liquid material, the techniques herein enable rotation of a 300 mm substrate up to about 2800-3200 rpm without turbulence effects, and without turbulence effects. The rotation of the 450 mm substrate is up to about 1200-1400 rpm or higher.

While only certain embodiments of the invention have been described hereinabove, it will be readily understood by those skilled in the art that many modifications of the embodiments are possible without departing from the novel teachings and advantages of the invention. of. Accordingly, all such modifications are intended to be included within the scope of the present invention.

102‧‧‧Substrate support (rotary chuck)

121‧‧‧ (outside) edge

125‧‧‧Working surface

127‧‧‧radial distance

150-1‧‧‧Outer ring

150-2‧‧‧ Inner ring

155‧‧‧ surface of the substrate

180‧‧‧Rotary axis

W‧‧‧ wafer

Claims (31)

A spin coating apparatus for coating a substrate, the spin coating apparatus comprising: a substrate holder configured to horizontally hold a substrate during a spin coating process; and a rotating mechanism coupled to the substrate holder The rotating mechanism is configured to rotate the substrate holder about a rotating shaft; a liquid dispenser configured to dispense a liquid material onto the working surface of the substrate when the substrate is disposed on the substrate holder The working surface has a circular shape and is planar and opposite the bottom surface of the substrate contacting the substrate holder; and an annular fluid flow member having a substrate surface configured to be positioned such that When the substrate is disposed on the substrate holder, the surface of the surface substrate is vertically above the annular portion of the working surface of the substrate, and the annular portion of the working surface extends from the outer edge of the working surface to the rotating shaft Calculating a predetermined radial distance at which at least a portion of the surface of the substrate is curved such that a specific vertical distance between the surface of the surface substrate and the working surface is relative to the rotation Radially varying from a specific radial distance; wherein the surface of the surface substrate has an outer annular portion and an inner annular portion, the inner annular portion being closer to the rotating axis than the outer annular portion, the surface of the surface substrate The annular portion is located above the inner portion of the annular portion of the working surface and has a first radius of curvature, and the annular portion outside the surface of the surface substrate is located above the edge portion of the annular portion of the working surface and has The second radius of curvature is different from the first radius of curvature, and the surface of the surface substrate is convex with respect to the working surface. The spin coating apparatus for coating a substrate according to claim 1, wherein a specific vertical distance between the surface of the surface substrate and the working surface is changed such that the specific vertical distance follows the rotation The radial distance from the axis is increased and decreased. A spin coating apparatus for coating a substrate according to claim 1, wherein the fluid flow member defines a circular opening vertically above a circular portion of the working surface, the circular portion being The axis of rotation extends to the predetermined radial distance. The spin coating apparatus for coating a substrate according to claim 1, wherein the first radius of curvature is between 20 mm and 90 mm, and wherein the second radius of curvature is between Between 1000 mm and 2000 mm. The spin coating apparatus for coating a substrate according to claim 4, wherein the first radius of curvature is between 50 mm and 70 mm, and wherein the second radius of curvature is between Between 1300 mm and 1500 mm. The spin coating apparatus for coating a substrate according to claim 1, wherein the surface of the surface substrate defines a shape of a truncated cone that is convex with respect to the working surface, and the surface of the surface substrate is The distance between the working surfaces is reduced in the radial direction towards the outer edge of the working surface. A spin coating apparatus for coating a substrate according to claim 6, wherein the surface of the face substrate has a curvature selected to improve drying uniformity during the spin coating process. The spin coating apparatus for coating a substrate according to claim 7, wherein a specific vertical distance between the surface of the surface substrate and the working surface is selected to cause a turbulent fluid flow above the working surface. Minimize to a minimum. A spin coating apparatus for coating a substrate according to claim 1, wherein the fluid flow member comprises two or more segments, and the at least one segment is configured to move away from adjacent segments. A spin coating apparatus for coating a substrate according to claim 9, wherein the fluid flow member comprises four segments configured to mechanically move away from adjacent segments. The spin coating apparatus for coating a substrate according to claim 1, wherein the surface of the surface of the fluid flow member comprises a plurality of planar radial segments, and the fluid flow member has a plurality of linearities. The curvature of the cross section formed by the segments. A spin coating apparatus for coating a substrate according to claim 1, wherein the fluid flow member defines an opening such that the fluid flow member forms a partial ring located above the substrate holder. A method for manufacturing a semiconductor device, the method comprising the steps of: disposing a substrate on a substrate holder, the substrate holder horizontally holding the substrate, the substrate holder having a rotating shaft, the substrate having a contact a bottom surface of the substrate holder and a working surface opposite the bottom surface; a fluid flow member disposed above the substrate holder, the fluid flow member having a substrate surface, the step of disposing the fluid flow member comprising the surface of the substrate Provided at a predetermined average vertical distance above the vertical surface of the working surface, at least a portion of the surface of the surface substrate is curved so that a specific vertical distance between the surface of the surface substrate and the working surface is relative to the rotation The shaft varies radially from a particular radial distance; a liquid material is dispensed onto the working surface of the substrate through a liquid distributor positioned above the substrate; and the substrate is rotated by a rotating mechanism coupled to the substrate holder And the substrate holder, the liquid material is diffused throughout the working surface of the substrate. The method for manufacturing a semiconductor device according to claim 13, further comprising the step of maintaining the surface of the surface substrate above the working surface at a predetermined average before dispensing the liquid material onto the working surface. Where the vertical distance is; and after the dispensing of the liquid material begins, the predetermined average vertical distance is reduced to a second predetermined average vertical distance by a vertical motion mechanism. The method for manufacturing a semiconductor device according to claim 14, wherein the surface of the surface substrate has an outer annular portion and an inner annular portion, the inner annular portion being closer to the rotation than the outer annular portion. a shaft, the annular portion of the surface of the surface of the substrate is radially curved, and the annular portion outside the surface of the surface substrate has a nearly linear radial slope, wherein the predetermined average vertical distance is reduced to the second predetermined average The step of perpendicular distance causes the annular portion outside the surface of the face substrate to be located less than about 4 mm from the working surface, and when the working surface has a diameter of about 300 mm, the outer annular portion is attached from the axis of rotation Extending from a radial distance of about 80-120 mm, and when the working surface has a diameter of about 450 mm, the outer annular portion is at a radial distance of about 100-170 mm from the axis of rotation extend. The method for manufacturing a semiconductor device according to claim 14, wherein the step of reducing the predetermined average vertical distance to the second predetermined average vertical distance occurs from the beginning of dispensing the liquid material to the The working surface starts at a predetermined time. The method for manufacturing a semiconductor device according to claim 14, further comprising the step of rotating the surface of the surface substrate in the same direction of rotation as the substrate holder, such that the surface of the surface substrate is approximately The working surface rotates at the same angular velocity. The method for manufacturing a semiconductor device according to claim 13, wherein the step of disposing the fluid flow member over the substrate holder comprises mechanically combining a plurality of fluid flow member segments to form the fluid Flow component. The method for manufacturing a semiconductor device according to claim 13, further comprising the step of maintaining the surface of the surface substrate at the first time period before dispensing the liquid material onto the working surface. a predetermined average vertical distance above the surface; after the beginning of dispensing the liquid material, the predetermined average vertical distance is reduced to a second predetermined average vertical distance by a vertical motion mechanism during a second time period; and The time period increases the predetermined average vertical distance to a third predetermined average vertical distance while maintaining the substrate to rotate on the substrate support. A spin coating apparatus for coating a substrate, the spin coating apparatus comprising: a substrate holder configured to horizontally hold a substrate during a spin coating process; and a rotating mechanism coupled to the substrate holder The rotating mechanism is configured to rotate the substrate holder about a rotating shaft; a liquid dispenser configured to dispense a liquid material onto the working surface of the substrate when the substrate is disposed on the substrate holder The working surface is planar and opposite the bottom surface of the substrate contacting the substrate holder; and a fluid flow member having a substrate surface, the fluid flow member being configured to be positioned such that the substrate is disposed on the substrate The surface of the substrate is vertically above the working surface of the substrate, the fluid flow member defining a substantially circular opening centered on the axis of rotation, the fluid flow member being configured such that the defined The diameter of the opening can be increased and decreased. The spin coating apparatus for coating a substrate according to claim 20, wherein the fluid flow member comprises a diaphragm member and an annular substrate. The spin coating apparatus for coating a substrate according to claim 21, wherein the diaphragm member comprises a plurality of blades configured to slide over each other to increase or decrease the defined The diameter of the opening. The spin coating apparatus for coating a substrate according to claim 22, wherein the plurality of blades are attached to a mounting ring by a plurality of rods, so that rotating the mounting ring causes The vanes increase or decrease the diameter of the defined opening. A spin coating apparatus for coating a substrate, the spin coating apparatus comprising: a substrate holder configured to horizontally hold a substrate during a spin coating process; and a rotating mechanism coupled to the substrate holder The rotating mechanism is configured to rotate the substrate holder about a rotating shaft; a liquid dispenser configured to dispense a liquid material onto the working surface of the substrate when the substrate is disposed on the substrate holder The working surface has a circular shape and is planar and opposite the bottom surface of the substrate contacting the substrate holder; and an annular fluid flow member having a substrate surface configured to be positioned such that When the substrate is disposed on the substrate holder, the surface of the surface substrate is vertically above the annular portion of the working surface of the substrate, and the annular portion of the working surface extends from the outer edge of the working surface to the rotating shaft Calculating a predetermined radial distance, one of the surfaces of the surface of the substrate is curved, such that a specific vertical distance between the surface of the surface substrate and the working surface is relative to the axis of rotation The particular radial distance and the radial variation; Wherein the surface of the surface substrate has a linear outer annular portion and a curved inner annular portion, the curved inner annular portion is closer to the rotating axis than the linear outer annular portion, and the curved inner annular portion of the surface of the surface substrate Located above the inner portion of the annular portion of the working surface and having a radius of curvature, the linear outer annular portion of the surface of the face substrate is positioned over the edge portion of the annular portion of the working surface. The spin coating apparatus for coating a substrate according to claim 24, wherein a specific vertical distance between the surface of the surface substrate and the working surface is changed such that the specific vertical distance follows the rotation The radial distance from the axis is increased and decreased. A spin coating apparatus for coating a substrate according to claim 24, wherein the fluid flow member defines a circular opening vertically above a circular portion of the working surface, the circular portion being The axis of rotation extends to the predetermined radial distance. A spin coating apparatus for coating a substrate according to claim 24, wherein the linear outer annular portion of the surface of the face substrate has a linear radial slope. The spin coating apparatus for coating a substrate according to claim 24, wherein the linear outer annular portion of the surface of the surface substrate is flat, so that the fluid flow member is located on a working surface of the substrate When vertically above, the working surface has a substantially fixed vertical distance from the linear outer annular portion of the surface of the face substrate. The spin coating apparatus for coating a substrate according to claim 28, further comprising a vertical movement mechanism configured to: when the substrate is disposed on the substrate holder, the surface is configured The average vertical distance between the surface of the substrate and the working surface increases or decreases. The spin coating apparatus for coating a substrate according to claim 29, wherein the vertical movement mechanism is configured to set a vertical distance between the outer annular portion and the working surface to less than 5 mm . The spin coating apparatus for coating a substrate according to claim 28, wherein a radius of curvature of the curved inner annular portion of the surface of the surface substrate is between 20 mm and 90 mm.