JP2012023282A - Semiconductor device manufacturing method and semiconductor device manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device manufacturing method which can remove unnecessary residual films in a bevel portion.SOLUTION: The semiconductor device manufacturing method comprises the steps of measuring an eccentricity amount of a film formed on a wafer with respect to the wafer, adjusting a location of the wafer on a stage of an etching apparatus based on the eccentricity amount and removing a film at a bevel portion of the wafer by etching.

Description

  The present invention relates to a semiconductor device manufacturing method and a semiconductor device manufacturing apparatus.

  The semiconductor device manufacturing process includes a patterning process in which a wiring pattern is formed in a conductive material film and an opening pattern for a plug is formed in an insulating material film. In the patterning process, a resist pattern corresponding to the circuit pattern is formed on the material film provided on the wafer surface by a photolithography technique, and the material film is etched using the resist pattern as a mask to obtain the desired material film. To the shape of When a resist pattern is formed, if foreign matter such as dust is placed on the material film, the resist pattern may be deformed by the foreign matter, or the foreign matter itself may become a mask during etching, preventing normal etching processing. It may be. In that case, a shape matching the circuit pattern cannot be formed on the material film.

  The foreign matter that causes the pattern defect is mainly one of the resist and material film shaved during processing and the base film exposed by processing the material film. Particularly in recent years, foreign matter scattered from the vicinity of the outer periphery of the wafer has become a problem. The vicinity of the outer periphery of the wafer is called a bevel portion. The bevel portion is a name that combines the end surface that is perpendicular to the main surface of the wafer and the inclined surface on the main surface side and the inclined surface on the back surface side adjacent to the end surface on the outer periphery of the wafer. .

  The reason why foreign matters are scattered from the bevel portion is considered as follows. In recent years, the tendency to increase the number of semiconductor devices formed on one wafer as much as possible has increased, and it has become necessary to form a pattern to the very periphery of the wafer. For this reason, the material film is formed up to the outer periphery of the wafer, and the material film formed on the bevel portion is peeled off and easily scattered as foreign matter.

  In addition, although the region closer to the wafer center than the bevel portion is flat, as described above, the bevel portion has an end surface that is a plane parallel to the main surface of the wafer and a tilted surface. Not flat. In the processing process for the material film, etching is uniformly performed in a flat region of the wafer main surface, but the unevenness of the etching becomes large in the non-flat bevel portion, and the material film remains on the bevel portion, and the material film A part is peeled off and becomes a foreign object.

  In order to reduce foreign matter generated from the bevel portion, an unnecessary material film formed on the bevel portion may be removed before processing the material film. For this purpose, a plurality of manufacturers of semiconductor device manufacturing apparatuses have been made public. According to these publications, main film removal methods are roughly classified into three types: (1) polishing method, (2) wet etching method, and (3) dry etching method. An example of the method (3) by dry etching is disclosed in Patent Document 1.

JP-A-5-82478

  Patent Document 1 and other published film removal methods are inadequate as a method for removing unnecessary films remaining on the bevel portion in any method, and a part of the remaining film is peeled off. There is a problem of generating foreign matter. Because, as described above, processing variation is likely to occur in the bevel portion, and the residual state of the material film is various, so it is necessary to remove in accordance with the residual state, but in the method disclosed in Patent Document 1, This is because the removal method does not take into account the residual situation.

The method for producing a semiconductor device of the present invention comprises:
Measuring the amount of eccentricity of the film formed on the wafer relative to the wafer;
Adjusting the position of the wafer on the stage of the etching apparatus based on the amount of eccentricity;
Removing the film on the bevel portion of the wafer by etching;
It is what has.

  According to the present invention, etching is performed by measuring the amount of eccentricity of the film formed on the wafer and adjusting the position of the wafer on the stage of the etching apparatus based on the amount of eccentricity. Etching at different rates can be performed in accordance with the position of the remaining film in the bevel portion.

The semiconductor device manufacturing apparatus of the present invention is a semiconductor device manufacturing apparatus for etching a film in a bevel portion of a wafer,
A correction unit that adjusts the position of the wafer on the stage based on the amount of eccentricity of the film with respect to the wafer;
After the adjustment of the position of the wafer by the correction unit, an etching unit that processes the film in the bevel portion of the wafer;
A control unit for controlling the correction unit and the etching unit;
It is the structure which has.

  According to the present invention, it is possible to remove a film in accordance with an unnecessary film remaining state in a bevel portion, and it is possible to reduce the generation of foreign matters that cause a decrease in yield.

It is a flowchart which shows the manufacturing method of the semiconductor device by this embodiment. It is a figure for demonstrating a bevel part. It is sectional drawing and a top view for demonstrating an example of the film-forming method by sputtering method. It is sectional drawing and a top view for demonstrating an example of the film-forming method by plasma CVD method. It is sectional drawing of the wafer which shows the example of the film-forming state of the material film in a bevel part. It is a block diagram which shows the connection of a film | membrane inspection apparatus, an image processing apparatus, a data processing apparatus, and a bevel processing apparatus. It is a figure for demonstrating the structure of the film | membrane test | inspection apparatus shown in FIG. It is an example of the graph which shows the relationship between the outer peripheral position of a wafer, and the state of the film | membrane edge part in the position. It is an example of the graph which shows the relationship between the outer peripheral position of a wafer, and the state of the film | membrane edge part in the position. It is sectional drawing which shows one structural example of the bevel processing apparatus shown in FIG. It is a figure for demonstrating the method to adjust the position of a wafer by a bevel processing apparatus. It is a figure for demonstrating the etching process with respect to the laminated film which laminated | stacked the several material film.

  The semiconductor device manufacturing method according to the present embodiment will be described with reference to FIG. The thick arrows in FIG. 1 indicate the order of the wafer processing steps, and the thin arrows indicate the order of the information processing steps. In addition, [] described together with the processing content indicates the name of the device used in the process.

  A material film is formed on the wafer using a film forming apparatus (step 101). The material film may be a conductive material film or an insulating material film. The material films formed on the wafer by the film forming apparatus have different film forming states due to differences in the film forming method or individual differences of the film forming apparatuses. Among the indexes indicating the film formation state, the uniformity of the film thickness as well as the film density and the adhesion with the base film are the points for the quality determination regarding the film formation state. In particular, in this embodiment, since the film thickness variation of the bevel portion causes a problem in the subsequent process, it is necessary to reduce the variation.

  Here, the bevel portion will be described in detail with reference to FIG. As shown in FIG. 2, the bevel portion includes an end surface 2 at an end portion of the wafer 1, an inclined surface (hereinafter referred to as an upper inclined surface) 3 on the main surface side of the wafer 1 on which semiconductor elements are formed. , A general term that integrates an inclined surface (hereinafter referred to as a lower inclined surface) 4 on the back surface side of the wafer 1. Note that any one of apparatuses sold by a plurality of manufacturers is used as the film forming apparatus. The film thickness variation of the material film usually means a difference in film thickness, but the film thickness variation in the bevel portion includes not only the difference in film thickness but also the meaning of whether or not a film is attached. The film thickness variation of the material film in the bevel portion will be described in detail later with reference to FIGS.

  After step 101, the amount of eccentricity between the wafer and the material film is measured using a film inspection apparatus and an image processing apparatus. The amount of eccentricity is an index indicating the amount of deviation between the center of the wafer and the center of the region where the material film is formed on the wafer. Hereinafter, the region where the material film is formed on the wafer is referred to as a film forming region, and the outermost peripheral portion of the film forming region is referred to as a film end. The amount of eccentricity has a correlation with the position of the film end in the bevel portion of the wafer.

  For the measurement of the eccentricity, the step of acquiring the image by inspecting the edge of the material film in the bevel part (step 102), and extracting the position of the film edge of the bevel from the image, the eccentricity is determined. A calculation step (step 103) is required. In step 102, an image is acquired using an image processing apparatus, and in step 103, the amount of eccentricity is calculated using a film inspection apparatus. This amount of eccentricity is based on the distance from the reference surface of the wafer to the film end.

  The reference surface of the wafer referred to here is the end surface 2 or the main surface of the wafer 1 in the cross-sectional structure shown in FIG. When the reference surface of the wafer is the end surface 2, the eccentric amount at an arbitrary point x at the end of the film is the point x and the point z when the intersection point between the point x and the straight line passing through the center of the wafer and the end surface 2 is the point z. The length of the line segment connecting Note that a method for acquiring an image obtained by photographing the end portion of the material film in the bevel portion will be described in detail later with reference to FIG. 7, and a method for calculating the eccentricity amount will be described with reference to FIGS. The details will be described later.

  After step 103, a data processing device is used to determine the adjustment amount of the wafer position on the stage of the bevel processing device based on the above-described eccentricity (step 104). This adjustment amount is the amount of movement of the wafer position that is performed before etching the bevel portion. A method of determining the adjustment amount will be described in detail later with reference to Tables 1 and 2.

  After step 104, the bevel processing apparatus adjusts the wafer position by moving the wafer based on the adjustment amount calculated from the maximum eccentricity (step 105). After the wafer position is adjusted, the bevel material film is etched using a bevel processing apparatus (step 106). In step 106, at least a part of the material film in the bevel portion is removed. This adjustment method and the film state in the bevel portion after etching will be described in detail later with reference to FIGS.

  Next, the film formation state of the material film formed on the wafer will be described with reference to FIGS. FIG. 3A shows a cross section of a stage portion in a film forming apparatus when a film is formed on a wafer by sputtering, and FIG. 3B shows a plane thereof. A section taken along the line AA 'shown in FIG. 3B corresponds to FIG. The alternate long and short dash line shown in FIG. 3B is the x-axis and the y-axis, and the center of the wafer 1 is located at the origin which is the intersection of these axes.

  As shown in FIG. 3A, the wafer 1 is placed on the film formation stage 5. The end portion of the wafer 1 is covered with a shadow ring 6 for preventing film formation on the end portion. In such a state, the material film 7 is formed on the main surface side of the wafer 1. X1 shown in FIG. 3A is the diameter of the film formation region. The diameter X1 corresponds to a value defined as the inner diameter of the shadow ring 6 and coincides with the inner diameter of the shadow ring 6.

  Further, as shown in FIG. 3A, a region for accommodating the wafer 1 is provided in the shadow ring 6 when the end portion of the wafer 1 is covered with the shadow ring 6. This area is referred to as a storage area. As shown in FIG. 3A, when the inner diameter of the storage area is X2 and the diameter of the wafer 1 is X3, the inner diameter X2 is not the same as the diameter X3 of the wafer 1 and is designed to be larger than the diameter X3. Yes. Therefore, the material film 7 may be formed on the wafer 1 in a state where the center of the storage area of the shadow ring 6 is shifted from the center of the wafer 1. In this case, the material film 7 is formed so as to be shifted in the horizontal direction with respect to the main surface of the wafer 1 in accordance with the shift amount.

  A hatched portion shown in FIG. 3B corresponds to a film formation region of the material film 7. FIG. 3B shows a case where the material film 7 is formed so as to be shifted obliquely downward to the right in the drawing with respect to the wafer 1. The area of the region where the material film 7 is not formed is larger in the upper left direction of the drawing than in the lower right direction of the drawing. The eccentricity at the intersection between the end face of the wafer 1 and the line segment AA ′ in the upper left direction of the figure is A1, and the deviation at the intersection of the end face of the wafer 1 and the line segment AA ′ in the lower right direction of the figure. When the core amount is A2, the relationship is A1> A2.

  In the example shown in FIG. 3, the region where the material film 7 is not formed is represented by A1> A2, but the region where the material film 7 is not formed depends on the position where the wafer 1 is fixed to the film forming stage 5. Different.

  FIG. 4A shows a cross section of a stage portion in a film forming apparatus when a film is formed on a wafer by plasma CVD (Chemical Vapor Deposition), and FIG. 4B shows a plane thereof. A cross section of the AA 'portion shown in FIG. 4B corresponds to FIG. An alternate long and short dash line shown in FIG. 4B is the x-axis and the y-axis, and the center of the wafer 1 is located at the origin which is the intersection of these axes.

  As shown in FIG. 4A, the film forming stage 5 is mounted on the lower electrode 8. Opposite to the film forming stage 5, an upper electrode 9 is provided at a predetermined distance from the film forming stage 5. When a high frequency voltage is applied between the upper electrode 9 and the lower electrode 8 after placing the wafer 1 on the film forming stage 5 and introducing process gas into the chamber, plasma discharge is generated in the vicinity of the main surface of the wafer 1. Then, a product film 7 is formed on the wafer 1 by depositing a product by the plasma discharge on the wafer 1.

  The film forming state of the material film 7 on the bevel portion of the wafer 1 is not only the mounting position of the wafer 1 on the film forming stage 5 but also the flatness of the film forming stage 5 and the opposing surfaces of the upper electrode 9 and the lower electrode 8. Varies depending on parallelism. Since the film forming apparatus is not provided with the shadow ring 6 for shielding the bevel portion shown in FIG. 3, the material film 7 is also formed on the bevel portion. Therefore, as shown in FIG. 4A, the material film 7 may be formed on a part of the end surface 2 of the bevel portion.

  A hatched portion shown in FIG. 4B corresponds to a film formation region of the material film 7. In FIG. 4B, the outer periphery of the wafer 1 is indicated by a broken line. In FIG. 4B, the intersection of the end face of the wafer 1 and the line segment AA 'in the diagonally upper left direction of the figure is P21, and the eccentricity at the point P21 is P1. In FIG. 4B, the intersection of the end face of the wafer 1 and the line segment AA 'in the diagonally downward direction to the right is P22, and the eccentricity at the point P22 is P2. As can be seen from FIG. 4A, at least the upper inclined surface is covered with the material film 7 near the point P21 of the bevel portion. Further, in the vicinity of the point P22 of the bevel portion, not only the upper inclined surface but also the end surface is covered with the material film 7. In the wafer 1 shown in FIG. 4, since the material film 7 protrudes outward from the end face of the bevel portion, the eccentricity amounts P1 and P2 may be expressed as the protrusion amount P. In the example shown in FIG. 4, the protrusion amounts P1 and P2 have a relationship of P1 <P2.

  In the example shown in FIG. 4, the region where the material film 7 protrudes is represented by P1 <P2. However, the mounting position of the wafer 1 on the film formation stage 5 is the wafer on which film formation is performed. Since the flatness and the parallelism vary from film forming apparatus to film forming apparatus, the protrusion amount P is uniform for all wafers that have been formed in parallel by a plurality of film forming apparatuses. Must not.

  Note that the same reference numerals are used for the material film formed by the film forming method described with reference to FIG. 3 and the material film formed by the film forming method described with reference to FIG. It does not mean that the types and quality of films formed by the method are the same.

  Next, a case where a plurality of material films are stacked on the wafer 1 will be described. FIG. 5 is a cross-sectional view of a wafer showing an example of a film formation state of a material film in a bevel portion.

  FIG. 5A shows a state in which the material film 7b covers the end surface 2 of the wafer 1 through the material film 7a. FIG. 5B shows a state where the material film 7b covers a part of the upper inclined surface 3 of the wafer 1 through the material film 7a. Comparing FIG. 5A and FIG. 5B, it can be seen that the film thickness of the material film 7b is greatly different in the bevel portion. This will be described for the material films 7a and 7b using specific examples of film types and film thicknesses.

  The film type of the material film 7a is tantalum nitride (TaN), and the film type of the material film 7b is silicon nitride (SiN). A material film 7a having a thickness of 5 nm is formed on the wafer 1, and a material film 7b having a thickness of 80 nm is formed on the material film 7a. In this case, the film thickness Y of the material film 7b at the boundary between the main surface 1a of the wafer 1 and the upper inclined surface 3 will be compared.

  In the cross section shown in FIG. 5A, the horizontal distance Xa from the boundary to the end of the material film 7b is 400 nm, and the film thickness Y1 is 80 nm. In contrast, in the cross section shown in FIG. 5B, the horizontal distance Xb from the boundary portion to the end of the material film 7b is 150 nm, and the film thickness Y2 is 50 nm. When the ratio of the film thickness Y2 to the film thickness Y1 is calculated, (film thickness Y2 / film thickness Y1) × 100 = 62.5%. That is, when the film thickness of the material film 7b on the upper inclined surface 3 is compared, the film thickness Y2 is about 60% of the film thickness Y1, which is the case of FIG. 5B compared to the case of FIG. The film thickness of the material film 7b is as small as about 40%.

  Therefore, in the film formation state shown in FIG. 5A, the material film 7a on the end face 2 is covered with the material film 7b, whereas in the film formation state shown in FIG. The material film 7a is exposed from the middle to the outside.

  If the film formation states shown in FIGS. 5A and 5B exist on the same wafer 1, the difference in these film formation states causes a problem in a later manufacturing process. The contents of this defect will be described in detail later with reference to FIG.

  Next, the connection relationship among the film inspection apparatus, image processing apparatus, data processing apparatus, and bevel processing apparatus used in the process shown in FIG. 1 will be described. FIG. 6 is a block diagram showing connections between the film inspection apparatus, the image processing apparatus, the data processing apparatus, and the bevel processing apparatus. As shown in FIG. 6, the film inspection apparatus 10 is connected to a data processing apparatus 25 via an image processing apparatus 24. The bevel processing device 26 is connected to the data processing device 25.

  The image processing device 24 and the data processing device 25 are information processing devices such as a personal computer and a server device. The image processing device 24 includes a storage unit 142 and a control unit 140. The data processing device 25 includes a storage unit 152 and a control unit 150. Each of the control units 140 and 150 is provided with a memory (not shown) that stores a program and a CPU (Central Processing Unit) (not shown) that executes processing according to the program.

  Note that the film inspection apparatus 10 or the data processing apparatus 25 may have the function of the image processing apparatus 24. In this case, the image processing device 24 may not be provided. In the present embodiment, as shown in FIG. 6, a case where an apparatus for performing image processing is provided separately from the film inspection apparatus 10 and the data processing apparatus 25 will be described.

  Next, a method for acquiring an image obtained by photographing the end portion of the material film in the bevel portion will be described with reference to FIG. FIG. 7A is a cross-sectional view showing a configuration example of the film inspection apparatus shown in FIG. 6, and FIG. 7B is a plan view of the wafer fixed on the inspection stage as viewed from above.

  As shown in FIG. 7A, the film inspection apparatus 10 includes an inspection stage 11 that sucks and fixes the wafer 1, a support base 13 that rotates the inspection stage 11, and a sensor 16 that detects the notch of the wafer 1. , Cameras 18 and 19 for photographing the edge of the wafer 1, a light 21 for illuminating the edge of the wafer 1, and a control unit 120 for controlling each part.

  The control unit 120 includes a control unit 12 that controls the inspection stage 11, a control unit 14 that controls the support base 13, a control unit 17 that controls the sensor 16, a control unit 20 that controls the cameras 18 and 19, and a light. The control part 22 which controls 21 and the central control part 23 which supervises these control parts are provided. Each control unit of the control units 12, 14, 17, 20, and 22 is connected to a control target by a signal line. The central control unit 23 is connected to the control units 12, 14, 17, 20, and 22 by signal lines. The central control unit 23 is connected to the image processing device 24.

  The central control unit 23 is provided with a memory (not shown) for storing a program and a CPU (not shown) for executing processing according to the program. The central control unit 23 transmits a control signal to each of the control units 12, 14, 17, 20, and 22 in accordance with the procedure described in the program. Each of these control units, when receiving a control signal from the central control unit 23, causes the control target to execute a predetermined process. Thus, the central control unit 23 controls the operations of the control units 12, 14, 17, 20, and 22 so as not to interfere with each other.

  The support base 13 rotates the inspection stage 11 while fixing the wafer 1 around the center of the main surface of the wafer 1 according to an instruction from the control unit 14.

  The sensor 16 is a laser type detector. As shown in FIG. 7B, the notch 15 is a recess provided on the outer periphery of the wafer 1, and becomes the origin of the rotation angle when the wafer 1 is rotated about the center of the main surface of the wafer 1. . When the sensor 16 monitors the outer periphery of the rotating wafer 1 and detects the notch 15, the sensor 16 transmits a notch detection signal indicating that the notch 15 has been detected to the control unit 17.

  As shown in FIG. 7A, the camera 18 is provided at a position where the upper part of the end of the wafer 1 can be photographed, and the camera 19 is provided at a position where the side of the end of the wafer 1 can be photographed. . Further, the light 21 is provided at a position where both the upper side and the side of the end portion of the wafer 1 can be illuminated. Each of the cameras 18 and 19 is provided with a lens (not shown) and an image sensor (not shown). The image captured by the image sensor via the lens is converted into image data, which is electronic data, by the image sensor, and the image data is transmitted from the image sensor to the control unit 20 via a signal line.

  The origin of the rotation angle of the wafer is not limited to the notch, but may be determined based on an orientation flat (abbreviated as “orientation flat”). Further, the number of notches is not limited to one, but may be two or more. However, when there are two or more notches, it is only necessary to determine in advance how to place the origin from the positions of the two or more notches. In the present embodiment, as shown in FIG. 7B, a case where there is one notch 15 serving as the origin of the rotation angle of the wafer will be described.

  Next, an image acquisition method for the edge of the wafer 1 by the above-described film inspection apparatus 10 will be described with reference to FIG. It is assumed that a material film 7 is formed on the wafer 1.

  When the wafer 1 is placed on the inspection stage 11, the inspection stage 11 sucks and fixes the wafer 1. Subsequently, as shown in FIG. 7B, the film inspection apparatus 10 rotates the wafer 1 fixed to the inspection stage 11 clockwise at a speed of about 60 rpm. The number of rotations may be at least once. The direction of rotation of the wafer 1 is arbitrary, and is not limited to clockwise, but may be counterclockwise, but in the present embodiment, the case of clockwise rotation will be described. When the sensor 16 detects the notch 15 by rotating the wafer 1 at least once, the film inspection apparatus 10 recognizes the origin regarding the rotation angle of the wafer 1.

  Subsequently, the film inspection apparatus 10 rotates the inspection stage 11 in order to start photographing the edge of the wafer 1 from the origin of the rotation angle of the wafer 1, and the camera 18 and the camera 19 rotate the notch 15 of the wafer 1. Is moved to a position where it can be photographed. Then, the film inspection apparatus 10 activates the camera 18 or the camera 19, rotates the wafer 1 once at a speed of about 0.05 rpm around the center of the main surface of the wafer 1, and the bevel portion of the wafer 1. An image including both ends of the material film 7 is taken.

  However, it is assumed that the operator inputs information on which one of the two cameras of the camera 18 and the camera 19 is used to the central control unit 23 in advance. The operator determines which camera to use based on the film formation state of the material film 7 formed on the wafer 1. The film formation state includes, for example, the case described with reference to FIG. 3 and the case described with reference to FIG.

  When the material film 7 is formed by the sputtering method, the end of the material film 7 exists on the upper inclined surface 3 as in the material film 7b shown in FIG. 18 may be used. Further, when the material film 7 is formed by the plasma CVD method, the end portion of the material film 7 exists on the end face 2 as in the material film 7b shown in FIG. A camera 19 may be used. In this way, the operator knows in advance how to form the material film 7 and uses the two cameras depending on the film formation state, so that both the end of the material film 7 and the bevel portion of the wafer 1 can be removed. It is possible to take an image including the image.

  Further, when photographing with the camera 18 or the camera 19, by setting the photographing magnification in the camera 18 and the camera 19 in advance so that the boundary line between the end portion of the material film 7 and the bevel portion of the wafer 1 can be identified, It becomes possible to photograph these states appropriately.

  While the wafer 1 rotates once at a speed of about 0.05 rpm as described above, the film inspection apparatus 10 displays an image including both the bevel portion of the wafer 1 and the end portion of the material film 7 at the rotation angle of the wafer 1. A plurality of angle-dependent image data obtained by setting the rotation angle and the image data as a set is transmitted from the control unit 20 to the image processing device 24 via the central control unit 23.

  In this embodiment, the image data acquisition interval is set to be when the rotation angle of the wafer 1 is 1 °, but may be smaller than 1 ° or larger than 1 °. When the image data acquisition interval is 1 °, the number of angle-dependent image data is 360 including the case of the origin. When the image data acquisition interval is smaller than 1 °, the number of angle-dependent image data is larger than when the image data acquisition interval is 1 °, and therefore the film formation state in the bevel portion is analyzed in more detail. Is possible. On the other hand, when the image data acquisition interval is greater than 1 °, the number of angle-dependent image data is smaller than when the image data acquisition interval is 1 °. The rotation angle is a value that defines positions at regular intervals along the outer periphery of the wafer.

  Next, a method for calculating the distance from the reference surface of the bevel part to the film end from the image acquired by the film inspection apparatus 10 will be described with reference to FIGS. This distance calculation processing is executed by the image processing device 24 shown in FIG. In addition, about the structure, the same code | symbol is used about the structure similar to the structure shown to FIG. 6 and FIG.

  When the control unit 140 of the image processing apparatus 24 receives a plurality of angle-dependent image data regarding one wafer 1 from the film inspection apparatus 10, the control unit 140 stores the received angle-dependent image data in the storage unit 142. Subsequently, the control unit 140 extracts only the image data from the plurality of angle-dependent image data, analyzes the luminance distribution of the image, and sets a luminance threshold value for detecting the end surface 2 of the bevel portion and the end portion of the material film 7. And the control part 140 extracts the position data which shows each position of the bevel part and the edge part of the material film 7 for every image data from several angle dependence image data, and material film from the end surface 2 based on position data The distance X to the end of 7 is calculated. Thereafter, the control unit 140 creates a graph indicating the relationship between the rotation angle θ and the distance X by plotting the change in the distance X with respect to the rotation angle θ. An example of the created graph is shown in FIG.

  FIG. 8A is an example of a graph showing a change with respect to the rotation angle with respect to the data of the distance X from the end surface 2 to the end portion of the material film 7 in the upper inclined surface 3 photographed by the camera 18. FIG. 8B is an enlarged cross-sectional view of the bevel portion that is the measurement target of FIG. FIG. 8 shows an example of the material film 7 formed by the sputtering method.

  By the above-described arithmetic processing, the distance X is calculated on the straight line passing through the center of the main surface of the main surface 1a of the wafer 1 with the end surface 2 of the wafer as the reference surface. In the graph shown in FIG. 8A, Xa is an average value of distance X, and Xb is a maximum value. The angle θx is a rotation angle when the distance X becomes the maximum value Xb.

  When the control unit 140 calculates the average value Xa from the data of the graph shown in FIG. 8A and extracts the maximum value Xb and the angle θx at that time, the control unit 140 includes the average value Xa, the maximum value Xb, and the rotation angle θx. The image analysis processing data is transmitted to the data processing device 25.

  In the data indicating the change in the distance X with respect to the rotation angle, there is one maximum value and one minimum value of the distance X at positions where the rotation angles differ by 180 °, and there are no two maximum values. . This is because the variation in the position of the end portion of the material film 7 is not random variation but is caused by the shift of the center position of the film formation region due to the eccentricity as illustrated in FIG. Since there is only one maximal value for the distance X, for example, there is no error such that image analysis processing data cannot be sent due to the presence of two or more maximal points, and data to be transmitted to the data processing device 25 is missing. Never do.

  FIG. 9A is an example of a graph showing a change with respect to the rotation angle with respect to the data of the distance Y from the main surface 1a of the wafer 1 to the end portion of the material film 7 on the end surface 2 photographed by the camera 19. FIG. 9B is an enlarged cross-sectional view of the bevel portion that is the measurement target in FIG. FIG. 9 shows an example of the material film 7 formed by the plasma CVD method. Here, since the control unit 140 is the same as the above-described calculation process except that the distance Y is used instead of the distance X, detailed description thereof is omitted. Similarly to the above-described method, the control unit 140 extracts position data of the main surface 1a of the wafer 1 and the end portion of the material film 7 from each image data based on a plurality of angle-dependent image data. As shown in a), a graph in which a change in the distance Y with respect to the rotation angle θ is plotted is created.

  In the graph shown in FIG. 9A, the distance Y is calculated on the straight line perpendicular to the main surface 1a on the side surface of the wafer 1 with the main surface 1a of the wafer as the reference surface. Originally, the end 1A of the main surface 1a, which is a reference surface for measuring the distance Y, is covered with a material film 7 as shown in FIG. 9B. Therefore, the control unit 140 cannot extract position data with the end 1A as a reference plane from the image, and the distance Y from the corner 7B of the material film 7b to the end of the material film 7 is set as the distance Y. . However, the shift amount Yc between the end portion 1A and the corner portion 7B is only about 2 nm, and even if the position of the end portion 1A changes, the corner portion 7B does not follow the change, and the shift amount Yc increases. Therefore, no problem occurs even if the corner portion 7B is used as the reference plane.

When the control unit 140 calculates the average value Ya from the data of the graph shown in FIG. 9A and extracts the maximum value Yb and the angle θy at that time, the control unit 140 includes the average value Ya, the maximum value Yb, and the rotation angle θy. The image analysis processing data is transmitted to the data processing device 25. In the data indicating the change in the distance Y with respect to the rotation angle, there is one local maximum value and one local minimum value for the same reason as in the case of the distance X, and there are no two local maximum values. Since there is no error such that image analysis processing data cannot be sent due to the presence of two or more points that become maximal, data to be transmitted to the data processing device 25 is not lost.
The maximum values Xb and Yb calculated here correspond to the amount of eccentricity of the material film 7 with respect to the wafer 1.

  Next, a method for determining the adjustment amount of the wafer position, which is performed before etching the bevel portion, will be described. The wafer position adjustment amount determination process is executed by the data processing device 25 shown in FIG.

  The storage unit 152 of the data processing device 25 stores in advance a table for determining the adjustment amount of the wafer position from the image analysis processing data. An example of the table will be described below.

  Table 1 is an example of a table for determining the adjustment amount of the wafer position corresponding to the position data of the graph shown in FIG. In Table 1, the distance DX, which is the difference value (= Xb−Xa) between the average value Xa and the maximum value Xb, is divided in a certain range, and the adjustment amount Lx is described for each division.

  As shown in Table 1, it is not necessary to adjust the wafer position when the distance DX is 100 μm or less, and the adjustment amount is increased by 50 μm every time the distance DX increases by 100 μm. Here, the case where the distance DX is 400 μm or more is not set because the tolerance of the diameter X3 (see FIG. 3A) in the wafer 1 is ± 200 μm, so the distance DX is 400 μm or more. It is clear that it will not be. Further, the adjustment amount Lx with respect to the distance DX is an optimum value determined by the inventors through experiments. If the adjustment amount Lx is not linearly changed with respect to the distance DX, the effective effect is not recognized in the case of fine tracking, and the accuracy of the adjustment amount control is improved in the case of fine tracking. This is because there is a disadvantage that the configuration of the manufacturing apparatus becomes complicated.

  The control unit 150 of the data processing device 25 temporarily stores the image analysis processing data received from the image processing device 24 in the storage unit 152, and then calculates the distance DX from the image analysis processing data. Subsequently, the control unit 150 refers to Table 1 and determines the wafer position adjustment amount Lx corresponding to the calculated distance DX. Thereafter, the control unit 150 transmits adjustment data including information on the rotation angle θx and the adjustment amount Lx to the bevel processing device 26.

  Table 2 is an example of a table for determining the adjustment amount of the wafer position corresponding to the position data of the graph shown in FIG. In Table 2, the distance DY, which is the difference value (= Yb−Ya) between the average value Ya and the maximum value Yb, is divided in a certain range, and the adjustment amount Ly is described for each division.

  As shown in Table 2, even in this case, it is not necessary to adjust when the distance DY is 150 μm or less, and the adjustment amount is increased by 50 μm every time the distance DY increases by 150 μm. Here, the case where the distance DY is 600 μm or more is not set because the dimension Yd (see FIG. 2) of the end surface 2 of the wafer 1 is 350 ± 100 μm, so that the distance DY is 600 μm or more. It is clear that it should not be. The adjustment amount Ly with respect to the distance DY is also an optimum value determined by the inventor through experiments, and the reason why the adjustment amount Ly is not linearly changed with respect to the distance DY is the same as the reason described in the case of the distance DX.

  The control unit 150 of the data processing device 25 temporarily stores the image analysis processing data received from the image processing device 24 in the storage unit 152, and then calculates the distance DY from the image analysis processing data. Subsequently, the control unit 150 refers to Table 2 and determines the wafer position adjustment amount Ly corresponding to the calculated distance DY. Thereafter, the control unit 150 transmits adjustment data including information on the rotation angle θy and the adjustment amount Ly to the bevel processing device 26.

  Note that when the control unit 150 determines the adjustment amount of the wafer position, various methods are conceivable as to which of the table 1 and the table 2 is referred to by the control unit 150. For example, the operator may input an instruction as to whether the data processing device 25 should refer to Table 1 or Table 2 with respect to the analysis target, and the material film to be subjected to the bevel etching process is shown in FIGS. Information about which of these may be included in the image analysis processing data.

  Next, the configuration of the bevel processing apparatus 26 shown in FIG. 6 will be described with reference to FIG.

  As shown in FIG. 10, the bevel processing apparatus 26 includes a support plate 28 serving as a stage for holding the wafer 1 being etched, a lower electrode 32 and an upper electrode 33, and a high-frequency power source 34 that applies a high-frequency voltage to these electrodes. And a correction unit that adjusts the position of the wafer 1 and a control unit 160 that controls each unit. A pipe 29 and a pipe 30 for supplying process gas are connected to the process chamber 27, and a support plate 31 that holds the pipe 29 and the pipe 30 is provided below the upper electrode 33. A support plate 31, a lower electrode 32, and an upper electrode 33 are disposed in the center of the process chamber 27.

  The piping 29 is introduced into the process chamber 27 from a gas supply source (not shown) via a valve 36 and a supply port 39, and the piping 30 is connected to the process chamber 27 from a gas supply source (not shown) via a valve 37 and a supply port 39. Has been introduced. A pump 41 is connected to the process chamber 27 via an exhaust port 40. The pump 41 exhausts the gas after the etching process by the process gas in the process chamber 27.

  The correction unit includes a plurality of support pins 43 for holding the wafer 1, a drive unit 44 for raising and lowering the support pins 43, and an X stage and a Y stage for sliding the drive unit 44 in the X direction and the Y direction, respectively. (Hereinafter referred to as an XY stage) 46. The material of the support pin 43 is an alloy.

  The control unit 160 is connected to the valve 36 and the valve 37 via a signal line, the control unit 42 connected to the pump 41 via a signal line, and connected to the drive unit 44 via a signal line. A control unit 45, a control unit 47 connected to the XY stage 46 via signal lines, and a central control unit 48 connected to these control units via signal lines. The central control unit 48 is connected to the high frequency power supply 34 via a signal line not shown in the figure. The central control unit 48 is connected to the data processing device 25 by a signal line.

  The flow rate of the process gas supplied into the process chamber 27 is adjusted by the control unit 38 controlling the opening degree of the valve 36 and the valve 37. When the control unit 42 controls the pump 41, not only the gas after the etching process is exhausted but also the pressure in the process chamber 27 is adjusted. When the control unit 45 controls the drive unit 44, the plurality of support pins 43 are raised or lowered via the through holes provided in the support plate 28. When the control unit 47 controls the XY stage 46, the drive unit 44 slides and moves in parallel in the X direction and the Y direction. The XY stage 46 is not limited to moving along each of the X direction and the Y direction, and the X direction stage and the Y direction stage move at the same time, so that the drive unit 44 can move any position on the XY coordinates from the current position. You may move on a straight line to the position coordinates.

  The central control unit 48 is provided with a memory (not shown) for storing a program and a CPU (not shown) for executing processing according to the program. The central control unit 48 transmits a control signal to each of the control units 38, 42, 45, 47 and the high frequency power supply 34 according to the procedure described in the program. When receiving a control signal from the central control unit 48, each of these control units and the high frequency power source 34 execute a predetermined process. Control is performed by the central control unit 48 so that the operations of the control units 38, 42, 45, 47 do not interfere with each other.

  In the bevel processing apparatus 26, as shown in FIG. 10, the pipe 30 is divided into a plurality of discharge ports in the support plate 31, and the plurality of discharge ports are formed on the wafer 1 when the wafer 1 is held on the support plate 28. Arranged in the vicinity of the main surface inside the bevel.

  On the other hand, the discharge port of the pipe 29 in the support plate 31 is provided in the vicinity of the bevel portion of the wafer 1 when the wafer 1 is held on the support plate 28. Further, the lower electrode 32 and the upper electrode 33 are configured such that only the peripheral portions thereof are opposed to each other at the bevel portion of the wafer 1. As described above, in the bevel processing apparatus 26, the structure of the etching unit is a structure in which only the peripheral portions of the lower electrode 32 and the upper electrode 33 are opposed to the bevel portion of the wafer 1, and the process supplied via the pipe 29. By making the gas into plasma, only the material film of the bevel portion of the wafer 1 can be etched.

  A specific example of the etching process by the bevel processing apparatus 26 having the above-described configuration will be described. The unit of pressure Torr is 1 Torr≈133 Pa.

After the pressure in the process chamber 27 is set to 1.9 torr, sulfur hexafluoride (SF ₆ ) having a flow rate of 20 sccm and tetrafluoromethane (CF ₄ ) having a flow rate of 100 sccm are supplied to the process chamber 27 through a pipe 29 as process gases. By applying a high-frequency voltage with a power of 600 W between the upper electrode 33 and the lower electrode 32 from the high-frequency power source 34, these process gases are converted into plasma near the bevel portion. At this time, nitrogen (N ₂ ) having a flow rate of 90 sccm is supplied to the process chamber 27 via the pipe 30, so that the generated plasma does not flow to the central portion of the wafer 1, and the plasma region 35 is formed only near the bevel portion. It becomes possible to form.

  In the etching process in the plasma region 35, the etching amount tends to increase as it approaches the center of the region. This is because the plasma density gradient increases from the periphery to the center of the plasma region 35 by limiting the plasma generation region to the vicinity of the bevel. This will be described with reference to FIG. 10. Even in the same plasma region 35, in the plasma region 35b in the central portion, the plasma contributing to the etching increases, and as a result, the etching rate becomes the plasma region 35a in the peripheral portion. This is because the etching efficiency is improved.

  Next, a method for adjusting the position of the wafer 1 by the bevel processing apparatus 26 will be described with reference to FIG. FIG. 11 is a diagram showing a main part of a bevel processing apparatus for explaining a wafer position adjustment method.

  FIG. 11A is a plan view of the support plate 28, and FIG. 11B is a cross-sectional view thereof. FIG. 11C is an enlarged view of a portion surrounded by a broken line frame 170 shown in FIG. FIG. 11D is a cross-sectional view schematically showing how the etching process is performed after the position of the wafer 1 is adjusted.

  As shown in FIG. 11A, four support pins 43 are arranged on each of two straight lines orthogonal to each other through the center of the circular support plate 28. In the example shown in FIG. 11A, one of the two straight lines is a line parallel to the X axis, and the other is a line parallel to the Y axis. Of the four support pins 43 on the line parallel to the X axis, of the two support pins 43 near the center of the support plate 28 and of the four support pins 43 on the line parallel to the Y axis, Two support pins 43 on the side close to the center are arranged concentrically. Similarly, out of the four support pins 43 on the line parallel to the X axis, the two support pins 43 on the side close to the outer periphery of the support plate 28 and the four support pins 43 on the line parallel to the Y axis. The two support pins 43 on the side close to the outer periphery of the support plate 28 are arranged concentrically. FIG. 11B shows a cross-sectional structure of one of the two straight lines.

  When the drive part 44 raises the support pin 43, as shown in FIG.11 (b), it has adjusted so that protrusion amount Ya of the support pin 43 may be set to about 2-3 mm. For this reason, even if the warpage of the wafer 1 and the flatness of the support plate 28 are within the specified ranges, even a part of the wafer 1 does not come into contact with the support plate 28.

  Not only is the support plate 28 and the support pin 43 independent, but the inner diameter of the through hole provided in the support plate 28 is larger than the diameter of the support pin 43, so that the support pin 43 and the side wall of the through hole There is a margin between them. Therefore, by moving the XY stage 46 along each of the X axis and the Y axis, the wafer 1 held on the support pins 43 via the drive unit 44 provided on the XY stage 46 is within the above margin. It is possible to move in accordance with the adjustment amount determined by the data processing device 25. In this manner, the support pins 43 can be moved in parallel with the main surface of the wafer 1 and independently of the support plate 28 in the through holes provided in the support plate 28.

  A specific example of the dimensions of the support pins 43 and the through holes will be described. FIG. 11C is an enlarged view of a portion surrounded by a broken line frame 170 shown in FIG. In the plan view of FIG. 11C, the diameter X4 of the support pin 43 is about 1.6 mm, and the inner diameter X5 of the through hole is about 5.8 mm. Based on these dimensions, the clearance between the support pin 43 and the through hole is 2.1 mm on any outer periphery of the support pin 43. The dimension of 2.1 mm is sufficiently larger than the maximum adjustment amount of 150 μm of the wafer 1 shown in Tables 1 and 2, and there is a problem that adjustment cannot be performed due to insufficient clearance when adjusting 150 μm. Absent.

  In the bevel processing device 26 configured as described above, when the central control unit 48 receives the adjustment data from the data processing device 25, the central control unit 48 stores the adjustment data in a memory (not shown). When the wafer 1 to be processed is set in the bevel processing apparatus 26, the central control unit 48 transports the wafer 1 to a load port (not shown) and detects the notch 15 (see FIG. 7B) of the wafer 1. Then, the position of the notch 15 and the center of the wafer 1 are recognized. Then, the central control unit 48 places the wafer 1 on the support pins 43 protruding from the through holes provided in the support plate 28 so that the center of the wafer 1 matches the machine center of the support plate 28.

  Subsequently, the central control unit 48 reads the adjustment amount (Lx or Ly) from the adjustment data stored in the memory (not shown) as a movement amount, and if it is determined that the wafer position needs to be adjusted, the central control unit 48 drives via the control unit 45. The support pin 43 is raised to the part 44. Then, the central control unit 48 reads the rotation angle (θx or θy) from the adjustment data as the movement direction, and the XY via the control unit 47 so that the bevel portion positioned at the rotation angle is near the center of the plasma region 35. The stage 46 is moved by the adjustment amount. Thereafter, the central control unit 48 lowers the support pin 43 to the drive unit 44 via the control unit 45. Further, the central control unit 48 performs the above-described etching process on the bevel portion of the wafer 1.

  When the wafer 1 is moved as described above, as shown in FIG. 11D, the insertion amount of the bevel portion into the plasma region 35b where the plasma density is high is large at the end portion 1c of the wafer 1. Thus, the plasma contributing to the etching increases, so that the etching amount at the end 1c can be increased. At this time, in the end portion 1d at a position where the rotation angle is 180 ° different from the end portion 1c, the insertion amount of the bevel portion is reduced as opposed to the end portion 1c, and the etching amount in the end portion 1d can be reduced. . Even if the etching amount with respect to the end 1d is reduced, as described with reference to FIG. 8 and FIG. 9, the position of the maximum value and the minimum value of the distance X or the distance Y is different by 180 ° depending on the rotation angle. At the end 1d corresponding to the value location, there is no problem because the etching amount needs to be reduced.

  Next, a film formation state in the bevel portion after the bevel portion is etched will be described with reference to FIG.

  Here, both FIG. 12A and FIG. 12C are cross-sectional views showing the state of the bevel portion before etching, which are the same as those shown in FIG. 5A and FIG. 5B. is there. FIG. 12A corresponds to FIG. 5A, and FIG. 12B corresponds to FIG. The material film 7a is tantalum nitride, and the material film 7b is silicon nitride.

  When the bevel material film 7b shown in FIG. 12A is etched, the underlying material film 7a remains as shown in FIG. 12B, and the material on the end face 2 and the upper inclined face 3 remains. The film 7a is exposed. This is because, in the state before etching, the material film 7b covers the end surface 2 and the film thickness Y1 of the material film 7b is thick, so that the etching amount for the material film 7a is insufficient. Since the remaining material film 7 a has poor adhesion to the wafer 1, it peels off and falls off in the exposed state, so that it becomes a foreign matter 49 and scatters onto the wafer 1. The foreign matter 49 causes the yield to be reduced by about 1.4% according to experiments.

  On the other hand, when the bevel material film 7b shown in FIG. 12C is etched, the underlying material film 7a is completely removed and does not remain as shown in FIG. 12D. Thus, the material film 7a can be prevented from peeling off and becoming a foreign substance.

  As described above, since the presence or absence of the material film 7a affects the yield, in the bevel processing performed by the bevel processing device 26, the beveled portion in the film forming state shown in FIG. By approaching the center of the high plasma region 35, it is possible to perform etching so that the state after etching is always the state shown in FIG.

  In this way, the bevel process of this embodiment can be applied to a laminated film in which a plurality of material films are laminated in the bevel portion.

  According to the semiconductor device manufacturing method of the present embodiment, the eccentricity of the material film formed on the wafer is measured with respect to the wafer, and the wafer on the stage of the etching apparatus is measured based on the eccentricity. By adjusting the position, etching with different etching rates is performed in accordance with the position of the remaining film in the bevel portion. Since the remaining state of the material film in the bevel portion is confirmed and the film is removed in accordance with the remaining state of the film, the unnecessary material film on the bevel can be sufficiently removed. As a result, it is possible to reduce the generation of foreign matter that causes a decrease in yield. Further, in the case where a plurality of films are stacked on the bevel portion, it is possible to prevent the base film of the bevel portion from being exposed and remain, and to reduce the generation of foreign matter due to peeling of the base film.

  Further, according to the semiconductor device manufacturing apparatus of the present embodiment, since the correction plate that adjusts the position of the wafer is provided on the support plate that fixes the wafer during etching, the amount of eccentricity is reduced before performing the etching process. The wafer position can be reliably optimized based on the above.

DESCRIPTION OF SYMBOLS 1 Wafer 2 End surface 7, 7a, 7b Material film 10 Film inspection apparatus 24 Image processing apparatus 25 Data processing apparatus 26 Bevel processing apparatus

Claims (12)

Measuring the amount of eccentricity of the film formed on the wafer relative to the wafer;
Adjusting the position of the wafer on the stage of the etching apparatus based on the amount of eccentricity;
Removing the film on the bevel portion of the wafer by etching;
A method for manufacturing a semiconductor device, comprising: In the manufacturing method of the semiconductor device of Claim 1,
The step of measuring the amount of eccentricity includes:
For each position at regular intervals along the outer periphery of the wafer, photographing an image including the bevel portion of the wafer and the end of the film;
For each image, reading the distance from the wafer reference plane to the end of the film;
And a step of obtaining the amount of eccentricity from the distance calculated for each image. In the manufacturing method of the semiconductor device of Claim 2,
The method of manufacturing a semiconductor device, characterized in that the positions at regular intervals are defined by a rotation angle of the wafer when the wafer is rotated about the center of the main surface of the wafer. In the manufacturing method of the semiconductor device according to claim 3,
The step of adjusting the position of the wafer based on the amount of eccentricity is based on the maximum value of the calculated distance and the rotation angle when the maximum value is reached, and the wafer moving direction and The manufacturing method of the semiconductor device characterized by including the process of determining the movement amount. In the manufacturing method of the semiconductor device according to claim 4,
The method of manufacturing a semiconductor device, wherein the movement amount is defined as a different value for each predetermined range of the distance. In the manufacturing method of the semiconductor device of any one of Claim 3 to 5,
A method of manufacturing a semiconductor device, wherein the origin of the rotation angle is a position based on an orientation flat or notch of the wafer. In the manufacturing method of the semiconductor device of any one of Claim 2 to 6,
The reference plane of the wafer is an end face in the bevel portion,
The distance is a distance from a reference surface of the wafer to an end portion of the film in a direction of a straight line passing through the positions at a predetermined interval from the center of the main surface of the wafer. . In the manufacturing method of the semiconductor device of any one of Claim 2 to 6,
The reference surface of the wafer is the main surface of the wafer;
The method of manufacturing a semiconductor device, wherein the distance is a distance from a reference surface of the wafer to an end of the film in a direction perpendicular to the main surface of the wafer. The method of manufacturing a semiconductor device according to claim 7.
A method of manufacturing a semiconductor device, wherein the film is a film formed by a sputtering method. The method of manufacturing a semiconductor device according to claim 8.
A method of manufacturing a semiconductor device, wherein the film is a film formed by a plasma CVD method. A semiconductor device manufacturing apparatus for etching a film in a bevel portion of a wafer,
A correction unit that adjusts the position of the wafer on the stage based on the amount of eccentricity of the film with respect to the wafer;
After the adjustment of the position of the wafer by the correction unit, an etching unit that processes the film in the bevel portion of the wafer;
A control unit for controlling the correction unit and the etching unit;
An apparatus for manufacturing a semiconductor device, comprising: The apparatus for manufacturing a semiconductor device according to claim 11, wherein
The correction unit is
Projecting on the stage through a plurality of through holes provided in the stage, and having a plurality of support pins capable of moving in parallel to the main surface of the wafer in the plurality of through holes. A semiconductor device manufacturing apparatus.

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