JPH1148115A - Device for grinding and polishing sphere, and grinding and polishing method for silicon sphere using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for grinding and polishing a sphere with high grinding and polishing efficiency, and suitable for relatively easy production of the sphere of high sphericity. SOLUTION: This device is provided with a freely rotating and vertically movable rotary shaft 7 with a passing groove for a worked sphere formed into a spiral shape in its periphery, and a housing 11 arranged in an outer periphery of the shaft 7 and having a grinding and polishing surface in its inner surface. An outer circumferential surface of a sphere is ground and polished into a sphere of high sphericity during a period when the worked sphere is rotatingly moved through the passing groove 6 formed into the spiral shape in the outer periphery of the rotary shaft 7 while contacting with an inner surface of the housing 11 for grinding and polishing. This device is applicable not only for a semiconductor silicon sphere as the worked sphere but also for a steel sphere, ceramic sphere and resin sphere, the worked sphere having sizes of about 0.1 mm-10 mm can be ground and polished with high sphericity, and high sphericity within ±0.2 μm of a roundness error is attained in the case of a sphere of 1 mm diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to grinding and polishing of a sphere such as spherical single-crystal silicon or polycrystalline silicon.

[0002]

2. Description of the Related Art Conventionally, when a semiconductor device is formed, a circuit pattern is formed on a plate-like single-crystal silicon wafer, and this is diced as needed to form a spherical single-crystal silicon when forming a semiconductor chip. A technique for forming a circuit pattern thereon is known.

[0003] The spherical silicon used here is required to be a true sphere, but there is no need for a spherical semiconductor chip. Therefore, only grinding and polishing apparatuses for silicon wafers have been commercialized. No device has been proposed for grinding and polishing spherical single-crystal silicon.

Conventionally, as a grinding and polishing apparatus for a spherical body, there is an apparatus used for manufacturing pachinko balls and bearings. However, in such a grinding and polishing apparatus, in addition to being strictly required to have a sphericity and a mirror surface, a large amount of spherical silicon which is easily scratched, easily oxidized, and serious for contamination, and is continuously produced. It is difficult to produce inline.

[0005]

SUMMARY OF THE INVENTION The present invention provides a sphere grinding and polishing apparatus which has a high grinding and polishing efficiency and is relatively easy to produce a sphere such as a single crystal silicon sphere having a high sphericity. .

[0006]

SUMMARY OF THE INVENTION A spherical grinding and polishing apparatus according to the present invention comprises: a rotating shaft having a passage formed in a helical shape formed on the outer periphery of a spherical body to be worked; And a housing having a ground and polished surface on its inner surface.

Thus, the outer peripheral surface of the spherical body is formed into a true spherical shape while the processing spherical body is rotationally moved in contact with the inner surface of the housing for grinding and polishing in a spirally formed passage groove formed on the outer peripheral surface of the rotating shaft. It is ground and polished.

In the apparatus of the present invention, the spherical body to be processed is
It can be applied not only to a semiconductor silicon sphere but also to a steel sphere, a ceramic sphere, and a resin sphere.
It can be ground and polished from a diameter of about 10 mm to a diameter of about 10 mm. In the case of a sphere with a diameter of 1 mm, the error of a perfect circle is ± 0.2 μm.
High sphericity within the range can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described based on an example in which the present invention is applied to the production of a single-crystal silicon sphere as a spherical substrate for a semiconductor having a diameter of 1 mm.

Embodiment 1 FIG. 1 shows the entire structure of a sphere grinding and polishing apparatus 10 according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a base of the apparatus,
The base 1 is provided with a support base 5 supported by a vertical movement guide 2 provided and vertically moved by a vertical stroke cylinder 3 and a supporter 4.

A support groove 5 is formed on the outer peripheral surface of the support groove 5 so as to have a spiral groove of a single-crystal silicon spherical body which is a polished spherical ball.
Is mounted to be rotatable and vertically movable. Further, the passage groove 6 provided on the outer periphery of the rotating shaft can be configured so that the depth gradually decreases as it goes down in the grinding area.

Reference numeral 8 denotes a rotation motor for driving the rotation shaft 7 to rotate. Reference numeral 9 denotes a coupling for transmitting the rotation force to the rotation shaft 7.

Further, a housing 11 made of an arbitrary hard material such as ceramics in addition to alloy steels such as high-speed steel and die steel is provided along the outer peripheral surface of the rotary shaft 7. Is provided with a hopper 12 containing a single crystal silicon spherical body M. The spherical body M in the hopper 12 is supplied between the passage groove 6 of the rotating shaft 7 and the housing 11 through the chute 13 by gravity, and is formed on the inner surface of the housing 11 by the vertical movement and rotation of the rotating shaft 7. It comes into sliding contact with the abrasive layer, and its outer peripheral surface is uniformly ground and polished to be finished into a true spherical shape.

Reference numeral 14 denotes a pool portion formed on the downstream side of the polishing area of the housing 11 with a diameter larger than that of the polishing area. The polished spherical body is temporarily stored in the pool section 14. Thereafter, they are aligned and can be supplied to the next circuit pattern forming step. Thus, the polished spherical body can continuously form a pattern without contacting the outside air. Since silicon is easily oxidized, a natural oxide film is formed when exposed to outside air, which often leads to a reduction in contact resistance and the like, and also eliminates problems such as occurrence of short circuit due to contamination.

In the case of this embodiment, a washing water supply unit 31 for supplying washing water and a washing water discharge unit 32 for discharging washing water after washing are further provided in the pool portion 14. . These arrangements and numbers can be set at any number and at any intervals as needed. As a result, the polished spherical body to be processed is washed while it is temporarily stored, so that the time required for manufacturing can be reduced. Further, an inert gas supply port 33 and an inert gas discharge port 34 are formed downstream of the cleaning water supply section 31 and the cleaning water discharge section 32. by this,
It is possible to dry the processed spherical body after the cleaning. Reference numeral 18 denotes an apparatus for supplying an abrasive as an accelerator for grinding and polishing a sphere. FIG. 2 shows a cross section of the housing 11. In FIG.
Is made of metal, and the spiral passage groove 6 formed on the outer peripheral surface over the entire length thereof is formed from the supplied sphere M so that the supplied spherical body can freely rotate in the groove.
It has a slightly larger diameter, and is formed such that a cross section having a depth, for example, approximately half the diameter of the sphere M forms a semicircle.

The housing 1 arranged on the outer periphery of the rotating shaft 7
1 has a grinding area 15 reduced in diameter from above to below in accordance with the diameter of the sphere from when the sphere to be supplied is charged to when it is finished.
Then, it is separated into a polishing region 16 for finish polishing which is formed almost vertically. The grinding region 15 is made of an abrasive layer made of diamond or borazon suitable for grinding, and the polishing region 16 is made of an abrasive layer made of fine diamond or borazon for finishing.

The lengths of the grinding region 15 and the polishing region 16 are desirably changed depending on the hardness and size of the ball to be ground and the density of the target surface.

In the apparatus shown in FIGS. 1 and 2, the sphere M supplied from the supply chute 13 to the grinding area 15 from the upper end opening 17 of the rotating shaft 7 and the housing 11 is supplied from the abrasive supply device 18. Rotating shaft 7
The outer surface of the sphere M is ground uniformly by being forcedly brought into contact with the abrasive layer in the grinding area 15 while being rotated by the rotation and vertical movement of the sphere M, and then is finished polished in the polishing area 16. The supply amount of the abrasive is appropriately changed depending on the degree of progress of the grinding and polishing.

Further, the reservoir portion 14 is provided with a delivery pipe 30 for sequentially delivering the aligned workpieces one by one. Desirably, a swirl flow forming means may be provided in the delivery pipe 30, and the spherical body to be processed may be conveyed on the swirl flow. Thereby, it is possible to prevent the surface from being scratched, and it is possible to reduce the defect occurrence rate of the formed circuit pattern.

The polished single-crystal silicon sphere is dried through a cathode water washing or anode water washing step, if necessary, and led to a subsequent circuit pattern forming step. At this time, the single-crystal silicon spherical body can be led to the next film forming step without contacting with the outside air, so that contamination can be prevented and the yield can be improved.

The housing is disposed adjacent to the grinding region having a tapered cross-section so that the distance between the housing and the surface of the passage groove of the rotary shaft is gradually reduced. It is also possible to provide a polishing region having a linear cross section so that the distance between the shaft and the surface of the passage groove is constant.

Embodiment 2 FIG. 3 shows an example in which the housing 11 is divided into a first compartment 11A and a second compartment 11B in series.
In 1A, grinding is performed, and in the second compartment 11B, polishing is performed.

Embodiment 3 FIG. 4 shows an example in which the housing is arranged horizontally. With this horizontal arrangement, the abrasive liquid uniformly contacts the single crystal spherical body to be processed, and higher sphericity can be obtained. In the case of this example, the housing 11S is provided in the horizontal direction, and the housing 11S is provided at a predetermined interval along the longitudinal direction.
A plurality of abrasive fluid supply ports 28 are provided in the upper part of the peripheral surface, and a abrasive liquid outlet 29 is provided in the lower part of the peripheral surface of the housing. As a result, the polishing liquid comes into contact with the silicon single crystal spherical body more uniformly, is discharged well, and a highly efficient and highly reliable mirror surface can be obtained. Multiple abrasive fluid supply ports 28
Is provided at the upper part of the peripheral surface of the housing,
Is provided at the lower part of the peripheral surface of the housing, and its direction can be changed.

Further, the housing shown in the above embodiment is a housing in which the passage of the spherical body to be processed is spirally formed on the inner periphery and is freely rotatable and movable up and down. A structure in which a sliding shaft having a ground and polished surface for sliding the outer periphery may be provided.

[0026]

According to the present invention, the following effects can be obtained.

(1) A sphere with high sphericity can be obtained in one step regardless of its material.

(2) Since two types of surface processing, grinding and polishing, can be performed simultaneously, the production efficiency is high.

(3) The surface of a silicon sphere which is easily scratched and easily oxidized can be extremely well mirror-polished, leading to a circuit element forming step.

(4) Since the entire structure is made up of unit parts, assembly is simple and maintenance is excellent.

(5) The rotating shaft and the grinding and polishing housing can flexibly cope with various ball diameters without reducing their functions.

[Brief description of the drawings]

FIG. 1 shows the overall structure of a sphere grinding and polishing apparatus according to an embodiment of the present invention.

FIG. 2 shows a first example of a sectional structure of a housing.

FIG. 3 shows another example of the sectional structure of the housing.

FIG. 4 shows still another example of the sectional structure of the housing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Base 2 Vertical movement guide 3 Vertical stroke cylinder 4 Supporter 5 Support base 6 Spherical passage groove 7 Rotation shaft 8 Rotation motor 9 Coupling 10
Spherical grinding and polishing apparatus 11, 11S Housing 11A, 11B Compartment 12 Hopper 13 Chute 14 Reservoir of polished sphere 15 Grinding area 16 Polishing area 1
7 Upper end opening 18 Abrasive supply device 28 Abrasive liquid supply port 29 Abrasive liquid outlet M sphere

Claims (8)

[Claims] 1. A rotating shaft having a passage formed in a spiral shape formed on the outer periphery of a spherical body to be processed and movable freely up and down, and an outer periphery of the spherical body arranged on the outer periphery of the rotating shaft and passing through the passage groove. And a housing having a ground and polished surface for sliding the sphere. 2. The sphere grinding and polishing apparatus according to claim 1, wherein an abrasive supply device is provided so as to face an installation upper portion of the housing. 3. The grinding and polishing housing is provided with a grinding region formed in a tapered cross section and adjacent to the grinding region so that the distance between the rotating shaft and the surface of the passage groove is gradually reduced, and 3. The sphere grinding and polishing apparatus according to claim 1, further comprising: a polishing region having a linear cross section so that a distance between the rotating shaft and a surface of the passage groove is constant. 4. The sphere grinding and polishing apparatus according to claim 1, wherein the grinding area of the grinding and polishing housing is made of a diamond abrasive layer. 5. The sphere grinding and polishing apparatus according to claim 1, wherein the grinding and polishing housing is divided into a plurality of compartments connected in series. 6. The sphere grinding and polishing apparatus according to claim 1, wherein the grinding and polishing housing is provided in a vertical direction. 7. The sphere grinding and polishing apparatus according to claim 1, wherein the grinding and polishing housing is provided in a horizontal direction. 8. A rotating shaft which is formed on the outer periphery of a passage groove of the spherical body to be processed in a spiral shape and is rotatable and movable up and down, and an outer periphery of the spherical body arranged on the outer periphery of the rotating shaft and passing through the passage groove. And a housing having a ground and polished surface that slides the sphere. A method for grinding and polishing a silicon sphere using a sphere grinding and polishing apparatus, comprising supplying a silicon sphere to a passage groove of the apparatus and rotating the rotating shaft. A method of grinding and polishing a silicon sphere, wherein the silicon sphere is slid on the ground and polished surface to perform grinding and polishing to obtain a silicon sphere having a mirror-polished surface.