JP2004106360A - Slit wafer supporting component and wafer cleaning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer manufacturing method capable of effectively removing oil, chips, abrasive particle and the like which are stuck to a wafer after cutting the wafer with a wire saw to be capable of reducing a time and a cost which are required for production of the wafer. <P>SOLUTION: A plurality of slits 109 are formed on a bottom surface of a groove 103 by providing the groove 103 on a semiconductor ingot to cut with the wire saw. The wafer 44 which is cut and suspended by being ranged in a fence state from the carbon slicing base 101 is installed to a wafer cleaning apparatus and cleaning liquid is injected from a nozzle provided above the groove 103. Since cleaning of a wafer upper part which is conventionally difficult can be effectively carried out and a post process is enabled to be omitted, the time and the cost which are required for manufacturing the wafer can be reduced. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the manufacture of semiconductor wafers, and more particularly to a wafer cleaning apparatus and a cleaning method for cleaning the front and back surfaces of a wafer after cutting, and in particular, the shape of a slice table and a slice base for holding a wafer in a wire saw. It is.
[0002]
[Prior art]
FIG. 1 is a flowchart showing a general mirror wafer manufacturing process. The outline of a general method for manufacturing a mirror-like wafer used as a raw material wafer for manufacturing a semiconductor device will be described with reference to FIG.
[0003]
First, a single-crystal semiconductor ingot is grown by a well-known Czochralski method (CZ method) or a floating zone melting method (FZ method) (STEP 1). Since the grown semiconductor ingot has a distorted outer shape (bending), the outer periphery of the semiconductor ingot is then ground by a cylindrical grinder or the like in an outer shape grinding step (STEP 2) to adjust the outer shape of the semiconductor ingot. This is sliced by a wire saw in a slicing step (STEP 3) and processed into a disc-shaped wafer having a thickness of about 300 to 1000 μm.
[0004]
When slicing a semiconductor ingot with a wire saw in this slicing step (STEP 3), the semiconductor ingot is adhered to a slice table, and the slice table is mounted on a slice base, and sliced into a plurality of wafers. Usually, carbon, ceramics, or the like is used as a material of the slice table. The surface of the sliced wafer has oil, cutting powder, abrasive grains and the like used at the time of slicing adhered thereto.
[0005]
Normally, a pre-wash cleaning step (STEP 4) is performed in a state where the wafer is bonded to the slice table (hereinafter, referred to as “before post-gas”), and after the wafers are peeled off from the slice table one by one (hereinafter, referred to as “pre-gas”). A post-wash cleaning step (STEP 5) is performed.
[0006]
As a method of the pre-cleaning step (STEP 4), as disclosed in, for example, JP-A-10-22238 and JP-A-2002-110591, a wafer is mounted on a wafer cleaning apparatus together with a slice base and a slice base. Then, the wafer is cleaned by spraying a cleaning solution from above and / or below the side surface of the wafer with an air blow or a shower nozzle.
[0007]
However, the cleaning of the wafer is insufficient only in the pre-wash cleaning step (STEP 4). Step (STEP5) is performed. That is, the wafers are separated one by one from the slicing table, and oil, cutting powder, abrasive grains, and the like adhering to the front and back surfaces of the wafer are scraped off with a rubber blade or brush. Further, a plurality of cleaning tanks are prepared as needed, and the wafers are cleaned by immersing the cleaning tanks in the cleaning tank and increasing the degree of cleaning stepwise.
[0008]
After that, the outer periphery of the wafer is chamfered in a chamfering step (STEP 6). Subsequently, a flattening process is performed by surface grinding and / or lapping (hereinafter, referred to as “surface grinding / lapping”) (STEP 7), and a chemical polishing process is performed in an etching process (STEP 8). Further, after the wafer surface is mirror-polished (STEP 9), the wafer surface is subjected to an epitaxial growth process (STEP 10) to obtain a mirror-polished wafer.
[0009]
[Problems to be solved by the invention]
However, in the conventional cleaning method in the pre-cleaning step (STEP 4), the cleaning liquid is jetted from the upper side of the wafer by two nozzles as shown in FIG. It was taking time. In addition, there is a problem that cutting powder, oil, abrasive grains, and the like remain in an uncleaned portion, and spot defects occur due to insufficient wafer cleaning capability after peeling.
[0010]
That is, in order to sufficiently clean the upper portion of the wafer shown in FIG. 12, it is necessary to perform air blowing or to spray a cleaning liquid upward from below the wafer. However, when the cut thickness of the wafer is 350 μm or less, the air blow causes the wafer to be violent, causing problems such as damaging the wafer and breaking the wafer.
[0011]
On the other hand, since the upper part of the wafer is only bonded to the slice table, when the cleaning liquid is sprayed upward from the lower part of the wafer, the bonded part is deformed by the force of the cleaning liquid, or the wafer falls off the slice table. There was a problem that Therefore, there is a problem that the upper portion of the wafer shown in FIG. 12 cannot be sufficiently cleaned.
[0012]
In addition, since the conventional pre-cleaning cleaning method is insufficient for cleaning the wafer, a post-cleaning post-cleaning step (STEP 5) must be performed in a post-process, which is troublesome and costly. In particular, when a plurality of wafer cleaning devices are used, there is a problem that not only the cost but also the size of the entire device is increased due to the wafer cleaning device and the wafer transfer device between the wafer cleaning devices.
[0013]
The invention according to the present application has been made to solve the above problems, and a first object of the invention is to sufficiently clean a portion of a wafer sliced by a wire saw in contact with a slice table. It is an object of the present invention to provide a wafer cleaning apparatus and a cleaning method thereof capable of improving the ability to remove cutting powder, oil, and abrasive grains before cleaning.
[0014]
Further, a second object of the invention according to the present application is to improve the cleaning efficiency before cleaning of a wafer sliced by a wire saw, shorten the cleaning time, reduce the amount of cleaning liquid used during cleaning, and reduce the cost of cleaning liquid. An object of the present invention is to provide a wafer cleaning apparatus and a cleaning method thereof that can be suppressed.
[0015]
Further, a third object of the invention according to the present application is to sufficiently perform cleaning of a wafer, thereby omitting or simplifying the post-cleaning step that has been conventionally performed, improving work efficiency, and increasing the work efficiency. It is an object of the present invention to provide a wafer cleaning apparatus and a cleaning method thereof that can save time and cost.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, a first invention according to the present application provides a support member for supporting a semiconductor ingot, a wire spirally wound at a predetermined pitch across a plurality of rollers, and A drive mechanism for moving in a linear direction, a head for holding the support member and approaching the semiconductor ingot toward the wire, the support member in a wire saw having a substantially rectangular parallelepiped shape, A support member having a curved surface in contact with the semiconductor ingot on one surface and a concave groove on another surface facing the one surface.
[0017]
A second invention according to the present application provides a support member for supporting a semiconductor ingot, a wire spirally wound at a predetermined pitch across a plurality of rollers, and a drive mechanism for moving the wire in a linear direction. And a head that holds the support member and moves the semiconductor ingot toward the wire, wherein the support member has a substantially rectangular parallelepiped shape, and has a curved surface that contacts the semiconductor ingot on one surface. A wire saw having a concave groove on the other surface opposite to the one surface.
[0018]
Further, a third invention according to the present application is to cut a semiconductor ingot with a wire saw, support a plurality of cut wafers, and inject a cleaning liquid or a cleaning gas into a gap between the wafers from an outer peripheral direction thereof. In a wafer cleaning apparatus, a plurality of slits are provided in a support member that supports the wafer, and a nozzle that injects the cleaning liquid or the cleaning gas from the slit toward the wafer is provided. is there.
[0019]
A fourth invention according to the present application is the wafer cleaning apparatus according to the third invention, wherein a pitch of the plurality of slits is equal to a pitch of a gap between the wafers. .
[0020]
Further, a fifth invention according to the present application provides a cleaning tank in which a wafer is accommodated, a support member for suspending and supporting the wafer, and a relative movement along the axial direction of the wafer accommodated in the cleaning tank. A nozzle for injecting a cleaning liquid or a cleaning gas toward a wafer housed in the cleaning tank, and a driving unit for relatively moving the nozzle and the wafer, wherein the nozzle is located above the support member. And a slit penetrating the support member from above to below the support member.
[0021]
Further, a sixth invention according to the present application is a slicing table that supports a wafer when slicing the wafer with a wire saw, wherein the slicing table has a concave groove on a surface facing a surface that contacts the wafer. Is the slice table.
[0022]
Further, a seventh invention according to the present application is a slice base for bonding and fixing a slice table that supports a wafer when slicing a wafer with a wire saw, and from the bonding surface for fixing the slice table to the bonding surface. A slice base having a through hole in an opposing surface.
[0023]
An eighth invention according to the present application is directed to a method of manufacturing a semiconductor wafer by cutting a semiconductor ingot with a wire saw and cleaning the cut wafer, wherein a slit is provided in a member supporting the wafer during the cleaning, A method for manufacturing a semiconductor wafer, comprising cleaning a wafer by spraying a cleaning liquid or a cleaning gas from above the wafer.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a method for manufacturing a semiconductor wafer according to the present application will be described in detail with reference to the drawings.
[0025]
[Embodiment 1]
First, a first embodiment will be described with reference to FIGS. FIG. 1 is a flowchart schematically showing a method of manufacturing a semiconductor wafer according to the first embodiment. The steps shown in the flow simply show steps in manufacturing a semiconductor wafer. As described below, it is essential that the manufacturing method of the present application includes a slicing step (STEP 3) and a pre-wash cleaning step (STEP 4) in the order of the flow shown in FIG. The number may vary depending on the specifications of the wafer and each manufacturer. Here, a process for manufacturing a semiconductor wafer having a diameter of 125 mm will be described.
[0026]
As described in the related art, first, a single-crystal semiconductor ingot is grown by the well-known Czochralski method (CZ method), the floating zone melting method (FZ method), or the like (STEP 1). Next, in an outer shape grinding step (STEP 2), the outer periphery of the semiconductor ingot is ground by a cylindrical grinder or the like to adjust the outer peripheral shape of the semiconductor ingot.
[0027]
Subsequently, the semiconductor ingot whose outer shape has been ground is moved to a slicing step (STEP 3). In this embodiment, a wire saw is used in the slicing step. FIG. 2 shows a schematic view of the wire saw. The wire saw 50 is provided with three rollers 55 to 57 rotatably between left and right brackets 51a and 51b (51b shows only a part by a two-dot chain line). In the wire saw 50 shown in the figure, an example is shown in which three rollers 55 to 57 are provided, but the number of rollers may be two or four or more.
[0028]
A wire 58 is spirally wound around the rollers 55 to 57 at a predetermined pitch, and the wire 58 reciprocates in the linear direction while rotating the rollers 55 to 57 reciprocally. The main body 50 is provided with a work support head 53 on which the semiconductor ingot 43 after the outer shape grinding is mounted so as to be movable in the vertical direction. The work support head 53 is moved up and down by the rotation of a work lifting motor 54 provided at the upper part. I do. Further, carbon, ceramics or the like is usually used as a material of the slice table. In this embodiment, carbon is used as a material of the slice table.
[0029]
The semiconductor ingot 43 is mounted on the work support head 53 via the carbon slice table 101 and the slice base 102. FIG. 3 is a perspective view showing a state in which the semiconductor ingot 43 is attached to the carbon slice table 101 mounted on the slice base 102, FIG. 4 (a) is a plan view, FIG. 4 (b) is a front view, and FIG. (C) is a side view. The semiconductor ingot 43 is fixed to the carbon slice table 101 with an epoxy resin adhesive, and the carbon slice table 101 is fixed to the slice base 102 with an epoxy resin adhesive.
[0030]
5A is a perspective view of the carbon slice table 101, FIG. 5B is a plan view, FIG. 5C is a front view, and FIG. 5D is a side view. As shown in FIG. 5A, the carbon slice table 101 has a substantially rectangular parallelepiped shape with a length (y) of 260 mm, a width (x) of 55 mm, and a height (z) of 20 mm. The lower surface is formed as a concave curved surface 105 having a curvature similar to the curvature of the outer periphery of the semiconductor ingot 43 so that the ingot 43 can be in close contact.
[0031]
Furthermore, a rectangular parallelepiped groove 103 is formed in the center of the carbon slicing table 101 in the longitudinal direction in order to secure a passage of the cleaning liquid jetted from the upper surface by the nozzle in the cleaning step after cutting the wire saw. The groove 103 is a groove having a length of 260 mm, a width of 30 mm and a depth of 11 mm provided from the upper surface in the center of the carbon slice table 101. As shown in FIG. 5C, the groove 103 does not penetrate the curved surface 105 before the slice. Therefore, the semiconductor ingot 43 can be bonded by applying an adhesive to the entire surface of the curved surface 105 of the carbon slice table 101 as in the conventional case.
[0032]
6A is a perspective view of the slice base 102, FIG. 6B is a plan view, FIG. 6C is a front view, and FIG. 6D is a side view. As shown in FIG. 6A, the slice base 102 has a length (y) of 270 mm and a width (x) below an upper rectangular parallelepiped 102a having a length (y) of 310 mm, a width (x) of 80 mm, and a height (z) of 15 mm. The lower rectangular parallelepiped 102b having a size of 65 mm and a height (z) of 40 mm is vertically overlapped and joined. The slice base 102 may be formed by bonding an upper rectangular parallelepiped 102a and a lower rectangular parallelepiped 102b formed of independent members, or may be integrally formed from one member. A portion where the upper rectangular parallelepiped 102a protrudes from the lower rectangular parallelepiped 102b forms a flange. In particular, the longitudinal flange portions 125a and 125b are used at the time of mounting to a wire saw and at the time of mounting to a wafer cleaning apparatus.
[0033]
This slice base 102 is formed with a rectangular parallelepiped slit 104 long in the longitudinal direction of the slice base 102 at the center of the slice base 102 in order to secure a passage of the cleaning liquid jetted from the upper surface by the nozzle similarly to the carbon slice table 101. I have. As shown in FIG. 6C, the slit 104 has a rectangular parallelepiped upper hole 104a having a length (y) of 260 mm, a width (x) of 50 mm, and a height (z) of 30 mm, and a height (y) of 260 mm and a width of (x). ) A rectangular parallelepiped lower hole 104b having a height of 30 mm and a height (z) of 25 mm penetrates the slice base 102 from the upper surface to the lower surface. In the examples shown in FIGS. 6A to 6D, the dimensions of the upper hole 104a and the lower hole 104b are different, but the vertical (y) and horizontal (x) dimensions of the upper hole 104a and the lower hole 104b are different. And a straight hole penetrating from the upper surface to the lower surface of the slice base 102. The material of the slice base 102 can be, for example, iron or SUS.
[0034]
Next, the operation of the wire saw will be described with reference to FIG. The slice base 102, the carbon slice table 101, and the semiconductor ingot 43 are mounted on the work supporting head 53 of the wire saw 50 while being fixed to each other. The work support head 53 is mounted by engaging the flanges 125a and 125b of the slice base 102 with the hooks 53a and 53b of the work support head 53 with the semiconductor ingot 43 arranged downward.
[0035]
Next, a processing liquid containing abrasive grains or the like is supplied while the wire 58 is reciprocated in the linear direction, and the semiconductor ingot 43 is pressed against the wire 58 so that the semiconductor ingot 43 is adjusted in accordance with the winding pitch of the wire 58. The wafer is cut into a plurality of disk-shaped wafers 44.
[0036]
In the wire saw 50, when the semiconductor ingot 43 is cut, the semiconductor ingot 43 is bonded and fixed to the carbon slicing table 101 with an adhesive in order to prevent the end of the semiconductor ingot 43 from being damaged. Therefore, as shown in FIG. 13, all of the sliced wafers 44 are adhered to the carbon slice table 101 and cut out in a state of being connected in a fence shape. In addition, in order to completely cut to the upper end of the semiconductor ingot 43, the carbon slice table 101 is pressed against the wire 58 beyond the upper end of the semiconductor ingot 43 to the carbon slice table 101 and cut.
[0037]
At this time, the wire 58 is cut to a position slightly beyond the curved surface 105 of the carbon slice table 101. Then, as shown in FIG. 13, a large amount of slits 109 are formed on the bottom surface of the groove 103 of the carbon slice table 101 according to the pitch of the wires 58 and penetrate therethrough. As a result, a passage for the cleaning liquid sprayed from the upper surface of the carbon slice table 101 is secured.
[0038]
Usually, the semiconductor ingot 43 is cut into a thickness of 350 μm or less. Since the wire saw is supplied with a working liquid containing abrasive grains of about 12 μm and sliced into a piano wire having a diameter of 80 to 160 μm, the cutting margin is about 150 μm. By the slicing process using the wire saw, the wafers 44 are connected in a fence shape and suspended from the slice base 102.
[0039]
Next, a description will be given of the pre-evacuation wafer cleaning step (STEP 4) in this embodiment. Normally, the surface of the sliced wafer 44 has oil, cutting powder, abrasive grains and the like used at the time of slicing adhered thereto, and therefore, cleaning is performed to remove the same. The cleaning is performed by attaching the wafer 44 and the carbon slicing table 101 to the wafer cleaning apparatus with the wafer fixed to the slice base 102.
[0040]
FIG. 7 is a plan view showing a state where the wafer 44 is not mounted in the wafer cleaning apparatus of the first embodiment, and FIG. 8 is a plan view showing a state where the wafer 44 is mounted and the wafer cleaning apparatus of the first embodiment. FIG. 9 is a longitudinal sectional view of the wafer cleaning apparatus according to the first embodiment. As shown in FIGS. 7 to 9, the wafer cleaning apparatus of this embodiment has a height of 560 mm, a length in the short direction of 550 mm, and a length in the long direction of 800 mm so that the wafer 44 can be mounted. It has a substantially rectangular parallelepiped shape.
[0041]
The wafer cleaning apparatus includes a substantially box-shaped housing 110. A lid 124 that can be opened and closed is pivotally mounted on an upper portion of the housing 110, and a cleaning tank 111 is provided inside the housing 110. The cleaning tank 111 has left and right side walls 111a and 111b along the longitudinal direction. A work support frame 120 having a U-shaped cross section for supporting the work 44 is fixed to the front and rear ends of the upper ends of the side walls 111a and 111b. are doing. As shown in FIG. 7, a groove 121 for fixing the slice base 102 is formed in the work supporting frame 120.
[0042]
By fitting the flanges 125a and 125b at both ends of the slice base 102 into the grooves 121, the wafer 44 connected in a fence shape is suspended on the slice base 102 together with the carbon slice table 101, and the work support frame is suspended. 120 is attached as shown in FIG.
[0043]
On the other hand, a nozzle feed motor 117 is fixed behind the upper end portion of the side wall 111a of the cleaning tank 111 with its rotation axis arranged in the longitudinal direction. The nozzle feed motor 117 has a male screw 116 for a screw feed mechanism formed on an extension of its rotary shaft. The tip of the male screw 116 is fitted on the inner peripheral wall of the ball bearing 115 whose outer periphery is fixed to the side wall 111a, and is supported so as to be able to rotate smoothly with respect to the side wall 111a. Then, the male screw 116 provided on the rotation shaft by the rotation of the nozzle feed motor 117 rotates on the spot.
[0044]
A female screw 113 non-rotatably fixed to the side of the moving base 112a is screwed into the male screw 116, and the female screw 113 moves back and forth by rotation of the male screw 116. Since the female screw 113 is fixed to the moving base 112a, the moving base 112a moves in the longitudinal direction of the wafer cleaning apparatus together with the female screw 113 by the rotation of the male screw 116. Further, as shown in FIG. 9, a concave dovetail groove 114a serving as a guide for front-rear operation is provided on the lower surface of the movable base 112a, and a convex guide rail 119a provided on the upper surface of the side wall 111a in a horizontal direction. Mating. Then, the movable base 112a is guided by the guide rail 119a, and is screwed in the longitudinal direction by the screw feed mechanism in a stable state.
[0045]
A convex guide rail 119b is also provided at the upper end of the side wall 111b over the horizontal in the longitudinal direction. Further, a concave dovetail groove 114b serving as a guide at the time of front-rear operation is fitted to a movable base 112b provided on the lower surface. A substantially rectangular parallelepiped nozzle support frame 118 is fixed to the moving base 112b and the moving base 112a. Since the moving base 112b is fixed to the moving base 112a via the nozzle support frame 118, the moving base 112b moves longitudinally in synchronization with the longitudinal movement of the moving base 112a. With the above mechanism, the nozzle support frame 118 can be moved by the screw feed mechanism along the longitudinal direction of the wafer 44 connected to the slice base 102 in a fence shape.
[0046]
As shown in FIG. 9, two nozzles 106 and 107 are fixed to the nozzle support frame 118 so as to be substantially symmetrical with the center line of the wafer 44 interposed therebetween, and the injection ports are provided obliquely downward, and the cleaning liquid is provided. It is provided so that it can be ejected from the upper left and right sides of the wafer 44. The injection angles of the nozzles 106 and 107 are fixed so as to be adjustable.
[0047]
Further, a nozzle 108 is provided at the center of the nozzle support frame 118 with its injection port facing downward so that the cleaning liquid is injected from above the wafer 44. The cleaning liquid ejected from the nozzle 108 flows between the respective wafers 44 through the slits 104 and the slits 109 (see FIG. 13) formed on the bottom surfaces of the grooves 103 to perform cleaning between the wafers.
[0048]
The nozzles 106 to 108 are connected to a cleaning liquid supply pump (not shown) via piping, and the cleaning liquid supply pump supplies a cleaning liquid made of water or the like containing a surfactant. In the slicing step using a wire saw (STEP 3), when a water-soluble processing liquid is used, the cleaning liquid only needs to flow, and when an oil-based processing liquid is used, the cleaning liquid is spouted vigorously. A discharge port 122 is provided at the bottom of the wafer cleaning apparatus, and the discharge port 122 is connected to a cleaning liquid recirculation apparatus (not shown) via a pipe 123. Further, the cleaning liquid recirculation device is connected to a cleaning liquid supply pump via a pipe, and the cleaning liquid is reused.
[0049]
Next, the operation of the wafer cleaning apparatus configured as described above will be described with reference to FIGS.
After the completion of the cutting by the wire saw, the wafers 44 in a fence-like state are taken out of the wire saw 50 together with the carbon slice table 101 and the slice base 102, and transported to the wafer cleaning apparatus. Then, by fitting the flange portions 125 a and 125 b of the slice base 102 into the grooves 121 of the work support frame 120, the wafer 44 is mounted on the wafer cleaning device.
[0050]
After mounting the wafer 44 on the wafer cleaning apparatus and closing the lid 124, the wafer cleaning apparatus is operated. When the wafer cleaning apparatus starts operating, the cleaning liquid is supplied to the nozzles 106 to 108 via a pipe from a cleaning liquid supply pump (not shown), and the cleaning liquid is ejected from the tip of each nozzle.
[0051]
The wafer 44 accommodated in the wafer cleaning apparatus is shower-cleaned by the cleaning liquid ejected from the nozzles 106 to 108. Specifically, the cleaning liquid sprayed from the nozzles 106 and 107 enters the cutting margins from above the left and right side surfaces of the wafer 44, and the cutting powder, oil, abrasive grains, and the like clogged in the cutting margins. Wash off. On the other hand, the cleaning liquid ejected from the nozzle 108 passes through the slits 104 and the slits 109 formed on the bottom surfaces of the grooves 103, penetrates into the respective cutting margins from above the wafer 44, and the cutting clogged in these cutting margins. Rinse powder, oil, abrasive grains, etc. In particular, it was difficult to sufficiently clean the cutting powder, oil, abrasive grains, and the like clogged in the cutting margin above the wafer 44 with only the cleaning liquid sprayed from above the side surface of the wafer 44 by the nozzles 106 and 107. Thus, the cleaning liquid sprayed from the nozzle 108 can be effectively cleaned.
[0052]
When the cleaning is started, the nozzle support frame 118 is moved by driving the nozzle feed motor 117, and the nozzles 106 to 108 are moved one way or reciprocally along the longitudinal direction of the slice base 102. As a result, the nozzles 106 to 108 move in the horizontal direction, so that the cleaning liquid is uniformly sprayed to all the gaps between the wafers 44, and the cutting powder adhered to all the wafer surfaces mounted on the wafer cleaning apparatus. , Oil, abrasive grains, etc. can be uniformly and sufficiently removed.
[0053]
The cleaning of the wafer 44 by the nozzles 106 to 108 is desirably performed until the nozzles 106 to 108 reciprocate a predetermined number of times. After the nozzles 106 to 108 have reciprocated a predetermined number of times, the cleaning liquid supply pump (not shown) is stopped, and the cleaning operation of the wafer 44 is completed. The cleaning liquid used for cleaning the wafer is recovered from a discharge port 122 provided at the bottom of the wafer cleaning apparatus to a cleaning liquid recirculation apparatus (not shown) via a pipe 123, and after performing a predetermined process, supplying the cleaning liquid. It is supplied to the pump and used again for cleaning the wafer.
[0054]
After the cleaning operation of the wafer 44 by the wafer cleaning device is completed, the lid 124 of the housing 110 is opened, and the cleaned wafer 44 is taken out of the wafer cleaning device. With the above series of operations, the pre-wash cleaning step is completed.
[0055]
After cleaning the wafers 44 before the cleaning, the wafers 44 are usually separated one by one from the carbon slice table 101. The wafer 44 is peeled from the carbon slice table 101 using a peeling agent such as hot water, oil or acetic acid.
[0056]
Thereafter, in a post-cleaning post-cleaning step (STEP 5), oil, cutting powder, abrasive grains and the like adhering to the front and back surfaces of the wafer 44 are scraped off with a rubber blade or brush, etc. Is prepared, and the wafer 44 is immersed in the cleaning tank to increase the degree of cleaning in a stepwise manner, thereby cleaning the wafer.
[0057]
However, in the present invention, the post-wash cleaning step (STEP 5) is not an essential step. As described above, since the effective cleaning is performed in the pre-cleaning step (STEP 4) and no uncleaned portion is generated, in the present embodiment, the cleaning is performed to the next chamfering step (STEP 6) without performing the cleaning after cleaning. It is possible to proceed. As described above, since a part of the manufacturing process can be omitted, a higher yield can be achieved as compared with the related art. Of course, it is also possible to perform the post-wash cleaning step between the pre-wash cleaning step (STEP 4) and the next chamfering step (STEP 6).
[0058]
After the chamfering step (STEP 6), flattening is performed by surface grinding and / or lapping (hereinafter, referred to as “surface grinding / lapping”) (STEP 7), and chemical polishing is performed in the etching step (STEP 8). Apply. Further, after the wafer surface is mirror-polished (STEP 9), the wafer surface is subjected to an epitaxial growth process (STEP 10) to obtain a mirror-polished wafer.
[0059]
[Embodiment 2]
Next, a second embodiment of the present invention will be described with reference to FIGS. The contents of STEP 1 to STEP 4 and STEP 6 to STEP 9 and the shapes of the carbon slice table 101 and the slice base 102 according to the present embodiment are the same as those of the above-described first embodiment, and therefore the description thereof is omitted. Only the structure of the cleaning device and its operation will be described.
[0060]
FIG. 10 is a plan view showing the wafer cleaning apparatus of the second embodiment with a wafer 44 mounted thereon, and FIG. 11 is a longitudinal sectional view of the wafer cleaning apparatus of the second embodiment.
As shown in FIGS. 10 and 11, the wafer cleaning apparatus of this embodiment has a substantially rectangular parallelepiped shape having a height of 560 mm, a length in the short direction of 550 mm, and a length in the long direction of 1450 mm. The wafer cleaning apparatus includes a substantially box-shaped housing 130, and a lid 144 that can open and close the upper portion of the housing 130 is pivotally fixed, and a cleaning tank 131 is provided inside the housing 130. The cleaning tank 131 is provided with left and right side walls 131a and 131b along the longitudinal direction, and a nozzle support frame 138 for supporting the nozzles 126, 127 and 128 is fixed above the side walls 131a and 131b.
[0061]
Two nozzles 126 and 127 are fixed to the nozzle support frame 138 so as to be substantially symmetric with respect to the center line of the wafer 44, and the nozzles are provided obliquely downward. It is provided so that it can be injected. The injection angles of the nozzles 126 and 127 are fixed so as to be adjustable. Further, a nozzle 128 is provided at the center of the nozzle support frame 138 so that its injection port faces downward, and the cleaning liquid is provided so as to be injected from above the wafer 44.
[0062]
The nozzles 126 to 128 are connected to a cleaning liquid supply pump (not shown) via piping, and the cleaning liquid is supplied by the cleaning liquid supply pump. On the other hand, a discharge port 142 is provided at the bottom of the wafer cleaning apparatus, and the discharge port 142 is connected to a cleaning liquid recirculation apparatus (not shown) via a pipe 143. Further, the cleaning liquid recirculation device is connected to a cleaning liquid supply pump via a pipe.
[0063]
A work feed motor 137 is fixed behind the upper end of the side wall 131a with its rotation axis arranged in the longitudinal direction. The work feed motor 137 has a male screw 136 for a screw feed mechanism formed on an extension of its rotary shaft. The tip of the male screw 136 is fitted to the inner peripheral wall of the ball bearing 135 whose outer periphery is fixed to the side wall 131a, and is supported so as to be able to rotate smoothly with respect to the side wall 131a. Then, the male screw 136 provided on the rotating shaft by the rotation of the work feeding motor 137 rotates on the spot.
[0064]
A female screw 133 non-rotatably fixed to the side of the moving base 132a is fitted to the male screw 136, and the female screw 133 moves back and forth by the rotation of the male screw 136. Since the female screw 133 is fixed to the moving base 132a, the moving base 132a moves in the longitudinal direction together with the female screw 133 by the rotation of the male screw 136. As shown in FIG. 11, a concave dovetail groove 134a serving as a guide during the longitudinal movement is provided on the lower surface of the movable base 132a, and fits into a convex guide rail 139a provided in the side wall 131a in the horizontal direction. I agree. Then, the moving base 132a is guided by the guide rail 139a, and is screwed in the longitudinal direction by the screw feeding mechanism in a stable state.
[0065]
On the other hand, a guide rail 139b is provided at the upper end of the side wall 131b so as to extend horizontally in the longitudinal direction. Further, a concave dovetail groove 134b serving as a guide at the time of forward and backward movement is fitted with a movable base 132b provided on the lower surface. A U-shaped work support frame 140 for supporting the wafer 44 is fixed on the moving base 132a and the moving base 132b. Since the moving base 132b is thus fixed to the moving base 132a via the work supporting frame 140, the moving base 132b moves back and forth in the longitudinal direction in synchronization with the front and rear movement of the moving base 132a.
[0066]
As shown in FIG. 11, a groove 141 for holding the slice base 102 is formed in the work supporting frame 140. By fitting the flange portions 125a, 125b at both ends of the slice base 102 into the grooves 141, the wafer 44 connected in a fence shape is suspended on the slice base 102 together with the carbon slice table 101, and the work supporting frame is suspended. 140 attached. With the above mechanism, the wafer 44 suspended on the work supporting frame 140 can be moved in the longitudinal direction of the cleaning tank 131 by the screw feed mechanism.
[0067]
Next, the operation of the wafer cleaning apparatus configured as described above will be described with reference to FIGS.
After completion of the cutting by the wire saw, the wafers 44 in a fence-like state are taken out of the wire saw together with the carbon slicing table 101 and the slice base 102, and transported to the wafer cleaning apparatus. Then, the wafer 44 is mounted on the work supporting frame 140 by fitting the flange portions 125 a and 125 b at both ends of the slice base 102 into the grooves 141 of the wafer cleaning device.
[0068]
After mounting the wafer 44 on the wafer cleaning apparatus and closing the lid 144, the wafer cleaning apparatus is operated. When the wafer cleaning apparatus starts operating, the cleaning liquid is supplied to the nozzles 126 to 128 via a pipe from a cleaning liquid supply pump (not shown), and the cleaning liquid is ejected from the nozzles 126 to 128. The wafer 44 accommodated in the wafer cleaning apparatus is cleaned by the cleaning liquid ejected from the nozzles 126 to 128 as in the first embodiment.
[0069]
When the cleaning is started, the work supporting frame 140 is driven by the work feeding motor 137 to move the wafer 44 one way or reciprocate along the longitudinal direction of the cleaning tank 131. As a result, the wafer 44 moves in the horizontal direction with respect to the nozzles 126 to 128, so that the cleaning liquid is uniformly sprayed to all the gaps between the wafers, and the cleaning liquid is sprayed on the surfaces of all the wafers 44 placed in the wafer cleaning apparatus. It is possible to uniformly and sufficiently remove the attached cutting powder, oil, abrasive grains and the like.
[0070]
The cleaning of the wafer 44 by the nozzles 126 to 128 is preferably performed until the wafer 44 reciprocates a predetermined number of times. After the wafer 44 has reciprocated a predetermined number of times, the cleaning liquid supply pump (not shown) is stopped to terminate the cleaning operation of the wafer 44. The cleaning liquid used for cleaning the wafer is recovered from a discharge port 142 provided at the bottom of the wafer cleaning apparatus to a cleaning liquid recirculation apparatus (not shown) via a pipe 143, and after a predetermined process is performed, the cleaning liquid is supplied. It is supplied to the pump and used again for cleaning the wafer.
[0071]
After the cleaning operation of the wafer 44 by the wafer cleaning device is completed, the lid 144 of the housing 130 is opened, and the wafer 44 cleaned by the transfer device (not shown) is taken out of the wafer cleaning device. With the above series of operations, the pre-wash cleaning step (STEP 4) is completed.
[0072]
In both the first and second embodiments, the outer shape grinding step (STEP 2) can be omitted, and the surface grinding / lapping step (STEP 7) and the etching step (STEP 8) can be omitted. You can also. Also, for example, the wafer manufacturing process according to the present invention described in each embodiment is an example, and it goes without saying that cleaning can be appropriately performed between each process. In particular, the steps from STEP 1 to STEP 10 can be partially replaced, omitted, or added within a range contrary to the gist of the present application.
[0073]
Further, there is no limitation on the material and size of the wafer in carrying out the present invention, and it is possible to manufacture not only semiconductor wafers of silicon, GaAs, GaP, InP and the like having a diameter currently manufactured but also the future. The present invention can be applied to a very large wafer.
[0074]
Further, in the first and second embodiments, the case where one nozzle is fixed above the wafer 44 and one nozzle is fixed above each of the left and right side surfaces is described, but the present invention is not limited to this. Not something. For example, only one nozzle may be provided above the wafer 44, and two nozzles may be provided above the wafer 44, and a total of eight nozzles may be provided one above the left and right sides, one on the left and right sides, and one below the left and right sides of the wafer 44. Provided, the nozzle may be swung. It is also possible to provide a plurality of nozzles in the longitudinal direction of the cleaning tank.
[0075]
Further, in the first and second embodiments, the case where the cleaning liquid is jetted from the nozzle to clean the wafer 44 has been described, but the present invention is not limited to this. For example, cleaning may be performed by blowing air on the wafer 44 instead of the cleaning liquid.
[0076]
Further, in the first and second embodiments, the case where the male screw is rotated by the motor to drive the nozzle or the work and the longitudinal movement of the female screw fitted to the male screw is used is described. However, the present invention is not limited to this. For example, the fixed portion of the linear motor may be provided on the side wall, and the movable portion of the linear motor may be attached to the lower surface of the moving base to drive the nozzle or the work.
[0077]
As described above, the present invention is not limited to the above embodiment, but relates to the structure and number of the nozzles themselves, the method of supporting the wafer 44 in the wafer cleaning apparatus, the method of driving the nozzle or the work, and the like. In, various applications and modifications can be made.
[0078]
For example, since the cutting accuracy with a wire saw is improved, if the wafer is sufficiently cleaned according to the present invention, a wafer having a predetermined flatness and cleanness without performing a surface grinding / lapping step, an etching step, or the like. Can be manufactured, and the manufacturing process can be greatly streamlined.
[0079]
[Implementation data]
The effects of cleaning the wafer 44 using the conventional manufacturing method and cleaning the wafer 44 using the cleaning method of the present invention will be specifically described below.
[0080]
According to the present invention, the pre-wash cleaning time required to obtain a predetermined degree of cleanliness when cleaning is performed by a conventional cleaning method is 20 minutes. On the other hand, the pre-wash cleaning time required to obtain the same cleanliness when the cleaning is performed by the cleaning method of the present invention is 10 minutes, and the cleaning efficiency is doubled. Was. Further, the amount of the cleaning liquid used during the pre-wash cleaning was 200 liters in the past, but was 100 liters in the present invention, and the unit price of the cleaning liquid was also halved.
[0081]
【The invention's effect】
According to the present invention, since the cleaning liquid can be sprayed from above the wafer, it is possible to easily remove cutting powder, oil, abrasive grains and the like above the wafer and to uniformly clean the entire surface of the wafer. Become.
[0082]
Further, according to the present invention, the showering time can be significantly reduced, and the work efficiency can be improved. As a result, it is possible to greatly reduce the amount of the cleaning liquid used for cleaning the wafer.
[0083]
According to the present invention, since the cleaning efficiency of the wafer is very high, the wafer can be sufficiently cleaned even if tap water is used as the cleaning liquid.
[0084]
Further, according to the invention of the present application, the post-cleaning cleaning step can be omitted, so that the manufacturing steps at the time of manufacturing a semiconductor wafer can be rationalized and the productivity can be improved. As a result, it is possible to shorten the manufacturing time of the semiconductor wafer, and to reduce the manufacturing cost of the semiconductor wafer and the space for the post-peeling wafer cleaning apparatus.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an outline of a method of manufacturing a semiconductor wafer according to the present invention.
FIG. 2 is a perspective view illustrating an appearance of a wire saw.
FIG. 3 is a perspective view showing a state where a semiconductor ingot is bonded to a carbon slice table of the present invention.
FIGS. 4A to 4C are a plan view, a front view, and a side view, respectively, showing a state where a semiconductor ingot is bonded to a carbon slice table.
FIGS. 5A to 5D are a perspective view, a plan view, a front view, and a side view of a carbon slice table, respectively.
FIGS. 6A to 6D are a perspective view, a plan view, a front view, and a side view of a slice base, respectively.
FIG. 7 is a plan view showing the wafer cleaning apparatus according to the first embodiment of the present invention in a state where no work is mounted.
FIG. 8 is a plan view showing a state in which a workpiece is mounted in the wafer cleaning apparatus according to the first embodiment of the present application.
FIG. 9 is a vertical sectional view of the wafer cleaning apparatus according to the first embodiment of the present application.
FIG. 10 is a plan view showing a state in which a work is mounted in the wafer cleaning apparatus according to the second embodiment of the present application.
FIG. 11 is a longitudinal sectional view of a wafer cleaning apparatus according to a second embodiment of the present application.
FIG. 12 is a conceptual diagram showing a conventional semiconductor wafer cleaning method.
FIG. 13 is a perspective view showing a state where a semiconductor ingot adhered to a carbon slice table is sliced.
[Explanation of symbols]
43 ... Semiconductor ingot
44 ... Wafer
50 ... Wire saw
51a ... bracket 51b ... bracket
53 ... Work support head
54 ... Work lifting motor
55 ... Laura
56 ... Laura
57 ... Roller
58 ... wire
101 ... Carbon slice table
102: slice base 102a: upper rectangular parallelepiped 102b: lower rectangular parallelepiped
103 ... groove
104: slit 104a: upper hole 104b: lower hole
105 ... curved surface
106 ... Nozzle
107 ... Nozzle
108 ... Nozzle
109 ... Slit
110 ... Housing
111: Cleaning tank 111a: Side wall 111b: Side wall
112a: Moving base 112b: Moving base
113 ... female screw
114a ... dovetail groove 114b ... dovetail groove
115 ... Ball bearing
116 ... male screw
117 ... Nozzle feed motor
118 ... Nozzle support frame
119a: guide rail 119b: guide rail
120 ... Work support frame
121 ... groove
122 ... outlet
123… Piping
124 ... lid
125a ... Flange part 125b ... Flange part
126 ... Nozzle
127 ... Nozzle
128 ... Nozzle
130 ... housing
131: Cleaning tank 131a: Side wall 131b: Side wall
132a: Moving base 132b: Moving base
133 ... female screw
134a ... Dovetail 134b ... Dovetail
135 ... Ball bearing
136 ... Male thread
137 ... Work feed motor
138 ... Nozzle support frame
139a: Guide rail 139b: Guide rail
140… Work support frame
141 ... groove
142 ... outlet
143 ... Piping
144 lid.

Claims (8)

A support member for supporting the semiconductor ingot, a wire spirally wound at a predetermined pitch across a plurality of rollers, a driving mechanism for moving the wire in a linear direction, and holding the support member toward the wire. And a head for bringing the semiconductor ingot closer, and the support member in the wire saw having:
The support member has a substantially rectangular parallelepiped shape, and has a curved surface that contacts the semiconductor ingot on one surface,
On the other surface facing the one surface, has a concave groove,
A support member characterized by the above-mentioned. A support member for supporting the semiconductor ingot,
A wire spirally wound at a predetermined pitch across a plurality of rollers,
A drive mechanism for moving the wire in a linear direction,
A head that holds the support member and brings the semiconductor ingot closer to the wire;
In a wire saw having
The support member has a substantially rectangular parallelepiped shape, and has a curved surface that contacts the semiconductor ingot on one surface,
On the other surface facing the one surface, has a concave groove,
A wire saw characterized by the above-mentioned. After cutting the semiconductor ingot with a wire saw, in a wafer cleaning apparatus that supports a plurality of cut wafers and injects a cleaning liquid or a cleaning gas from an outer peripheral direction to a gap between the wafers,
Providing a plurality of slits in a support member supporting the wafer,
A nozzle for injecting the cleaning liquid or cleaning gas from the slit toward the wafer is provided.
A wafer cleaning apparatus characterized by the above-mentioned. The pitch of the plurality of slits,
Equal to the pitch of the gap between the wafers,
The wafer cleaning apparatus according to claim 3, wherein: A cleaning tank in which wafers are stored;
A support member for suspending and supporting the wafer,
A nozzle that is supported so as to be relatively movable along the axial direction of the wafer accommodated in the cleaning tank and injects a cleaning liquid or a cleaning gas toward the wafer accommodated in the cleaning tank;
Driving means for relatively moving the nozzle and the wafer,
Disposing the nozzle above the support member;
The support member is provided with a slit penetrating downward from above the support member,
A wafer cleaning apparatus characterized by the above-mentioned. When slicing a wafer with a wire saw, it is a slicing table that supports the wafer,
A slice table having a concave groove on a surface facing a surface that contacts a wafer. When slicing a wafer with a wire saw, it is a slice base that adhesively fixes a slice table that supports the wafer,
A slice base having a hole penetrating from an adhesive surface for fixing the slice base to a surface opposing the adhesive surface. In a method of manufacturing a semiconductor wafer by cutting a semiconductor ingot with a wire saw and cleaning the cut wafer,
Providing a slit in the member supporting the wafer during the cleaning,
Cleaning the wafer by injecting a cleaning liquid or a cleaning gas from above the wafer,
A method for manufacturing a semiconductor wafer, comprising:

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