KR100457718B1 - Method and apparatus for manufacturing silicon wafer - Google Patents

Method and apparatus for manufacturing silicon wafer Download PDF

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Publication number
KR100457718B1
KR100457718B1 KR10-1996-0019031A KR19960019031A KR100457718B1 KR 100457718 B1 KR100457718 B1 KR 100457718B1 KR 19960019031 A KR19960019031 A KR 19960019031A KR 100457718 B1 KR100457718 B1 KR 100457718B1
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KR
South Korea
Prior art keywords
silicon wafer
grindstone
grinding
upper
lower
Prior art date
Application number
KR10-1996-0019031A
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Korean (ko)
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KR970008384A (en
Inventor
케이이찌 타나카
오사무 카가야
토오루 하타나카
Original Assignee
미쓰비시 마테리알 가부시키가이샤
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Publication date
Priority to JP19117195 priority Critical
Priority to JP95-191171 priority
Priority to JP96-004415 priority
Priority to JP441596 priority
Priority to JP8978496A priority patent/JP3923107B2/en
Priority to JP96-089784 priority
Application filed by 미쓰비시 마테리알 가부시키가이샤 filed Critical 미쓰비시 마테리알 가부시키가이샤
Publication of KR970008384A publication Critical patent/KR970008384A/en
Application granted granted Critical
Publication of KR100457718B1 publication Critical patent/KR100457718B1/en

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Classifications

    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02002Preparing wafers
    • H01L21/02005Preparing bulk and homogeneous wafers
    • H01L21/02008Multistep processes
    • H01L21/0201Specific process step
    • H01L21/02024Mirror polishing
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B24GRINDING; POLISHING
    • B24BMACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00Lapping machines or devices; Accessories
    • B24B37/04Lapping machines or devices; Accessories designed for working plane surfaces
    • B24B37/07Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool
    • B24B37/08Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool for double side lapping
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28DWORKING STONE OR STONE-LIKE MATERIALS
    • B28D1/00Working stone or stone-like materials, e.g. brick, concrete or glass, not provided for elsewhere; Machines, devices, tools therefor
    • B28D1/003Multipurpose machines; Equipment therefor
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B28WORKING CEMENT, CLAY, OR STONE
    • B28DWORKING STONE OR STONE-LIKE MATERIALS
    • B28D5/00Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02002Preparing wafers
    • H01L21/02005Preparing bulk and homogeneous wafers
    • H01L21/02008Multistep processes
    • H01L21/0201Specific process step
    • H01L21/02019Chemical etching

Abstract

The silicon wafer after slicing is inserted into the circular hole 15 of the carrier 14 and the silicon wafer is sandwiched between the upper side grindstone 13 and the lower side grindstone 12 to form the upper side grindstone 13 and the lower side grindstone 12 12 are rotated at a predetermined speed. Thus, both surfaces of the silicon wafer are simultaneously ground. At this time, the upper grindstone 13 is lowered by, for example, 100 占 퐉 while pressing the silicon wafer under a predetermined load. Further, the grinding liquid is supplied to the opening 13B of the upper grindstone 13 to control the temperature of the wafer to be constant. The supplied grinding liquid is always supplied to both surfaces of the silicon wafer through the grooves of the grinding surfaces of the grinding wheels 13 and 12 by the centrifugal force of the upper and lower grinding wheels 13 and 12 at all times.

Description

Method and apparatus for manufacturing silicon wafer

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a manufacturing method and a manufacturing apparatus for a large-diameter silicon wafer for manufacturing a highly integrated device, and more particularly to a technique for manufacturing a silicon wafer for simultaneously grinding both surfaces of a silicon wafer.

In a method of manufacturing a silicon wafer, a silicon wafer obtained by slicing a columnar silicon single crystal rod by an inner peripheral edge made of stainless steel is wiped on both surfaces with abrasive grains liberated by a rapping plate, thereby removing irregularities and damage generated in the slicing process The parallelism is improved. Then, this silicon wafer is subjected to mirror-polishing by chemical mechanical polishing, by removing the damaged layer (processed altered layer) formed by lapping by etching.

However, in order to remove the damaged layer on the surface caused by the lapping process, the etching off-off amount (machining allowance) in the etching is, for example, about 20 占 퐉, which requires a machining allowance of 30 占 퐉 or more. As a result, the unevenness (flatness) of the etched surface is also increased to, for example, about 1 mu m. Further, the amount of polishing after etching also becomes, for example, 10 占 퐉 or more, thereby deteriorating the flatness (for example, about 2.81 占 퐉 in total thickness variation (TTV) as shown in FIG.

In recent years, the diameter of silicon wafers has become 150 mm or 200 mm in diameter, 300 mm has been developed, and the device has been highly integrated. For example, in a 1G bit DRAM practically used in 2001, And the depth of focus are 0.18 탆 and 0.7 탆, respectively. Therefore, the required flatness is SFQD (site, front surface-reference, site least squares, deviation) and a flatness of 0.12 탆 should be achieved with an area of 26 x 32 mm (" THE NATIONAL TECHNOLOGY ROADMAP FOR SEMICONDUCTORS & See page 113 of the SEMICONDUCTOR INDUSTRY ASSOCIATION publication). In addition, when the diameter of the wafer is increased, the amount of distortion increases even with a slight curvature, so that the problem of warping becomes serious. That is, the distortion is generated not only in the manufacturing step of the silicon wafer but also in the film formation and the dry etching heat treatment in device processing. If the silicon wafer has a small warpage, it is possible to specify the warp at each step. That is, for example, even if a silicon wafer having an outer diameter of 300 mm is placed on a flat surface and its warpage is measured, the silicon wafer is deformed by its own weight and the apparent warpage is reduced to half or less. There is no other way to manage it.

In order to further increase the flatness, it is considered that the wafer surface after slicing is subjected to a polishing process with a damage of 3 탆 or less instead of a lapping process. The thickness after slicing is 700 占 퐉 for a 150 mm diameter wafer, 800 占 퐉 for a 200 mm diameter wafer, and 900 占 퐉 for a 300 mm diameter wafer.

As shown in Fig. 14 (A), the polishing pad, which is conventionally used, has an annular grinding blade, and a silicon wafer 32 mounted and fixed on the vacuum suction plate 31 is provided on one surface ).

14 (A), when the silicon wafer 32 is arranged on the vacuum adsorption plate 31 and the one surface of the silicon wafer 32 is ground, As shown in the figure, when the lower surface of the silicon wafer 32 is vacuum-adsorbed by the vacuum adsorption unit 31, the silicon wafer 32 is adsorbed on the vacuum adsorption unit 31 because the silicon wafer 32 is extremely thin as described above, Is a flat surface. The one-dot chain line 33 indicates the grinding surface. Therefore, as shown in (C) of Fig. 14, when the vacuum suction of the vacuum adsorption plate 31 is released after grinding, the surface (bottom surface) of the chuck of the silicon wafer 32 becomes the original shape, The opposite grinding surface becomes convex. That is, the vacuum-adsorbed slice surface is transferred to the opposite surface. When the grinding surface is vacuum-adsorbed and the opposite side surface is ground, the concave portion is transferred so as to be a convex portion after releasing the vacuum adsorption, so that the slice shape remains on the front and back surfaces of the silicon wafer. As a result, a light lapping process is required after grinding (see Japanese Patent Application Laid-Open No. 6-104229, filed by the present applicant), and the effect of reducing the damaged layer by grinding may become insufficient.

Therefore, in Japanese Patent Application Laid-Open No. 62-96400 filed by the applicant of the present application, after a section of an ingot having a high rigidity is subjected to grinding, the silicon wafer is sliced by slicing, and the grinding surface is vacuum-adsorbed A method of grinding a sliced surface is disclosed, and a silicon wafer having good parallelism and little distortion can be manufactured by this method.

In addition, in order to slice a large-diameter ingot having an outer diameter of 200 mm by the inner circumferential edge, the blade thickness of the inner circumferential blade is 0.38 占 퐉, and there is no large diameter stainless steel plate for slicing the large diameter ingot with an outer diameter of 300 mm. . Therefore, the wire has been practically used. The line diameter of the wire is 0.18 mu m, and the yield of the caprose (cut-off value) is reduced. However, the cut surface by the string fastener has a large unevenness compared with the inner circumferential edge sliced surface due to the vibration of the wire, and a step is generated because the feed of the wire is reversed during cutting. As shown in FIG. 15, as the portion of the silicon wafer 34 that is cut off becomes thicker, the both surfaces 34a (34a) of the silicon wafer 34 become thicker , 34b are tapered. Therefore, when the wire surface is vacuum-adsorbed and subjected to grinding processing, a crystal surface in the axial direction is displaced from the specified angle by about 0.02 to 0.05 deg.

Further, in order to manufacture a highly integrated device of 1 G bit or more, the back surface of the silicon wafer is polished to increase the flatness of the back surface reference, and the generation of particles is reduced to 1/10 or less. Therefore, it is possible to perform the half polishing of the back surface or the both-side simultaneous polishing disclosed in the above-mentioned JP-A-6-104229.

The following drawbacks can be considered in the above-described one-side grinding. That is, since sliced surfaces are transferred to both surfaces of a silicon wafer, they can not be replaced with lapping. Further, etching and chemical mechanical polishing processing values after that are increased, and it is difficult to obtain the desired flatness. Further, it is difficult to make the processing degrees of both sides the same, and distortion is likely to occur.

Therefore, the object of the present invention is to provide a double-side grinding method and apparatus that can produce a silicon wafer having a high flatness required in manufacturing a highly integrated device of 1 Gbit or more, instead of lapping. It is another object of the present invention to provide a double-side grinding method and apparatus which can reduce machining permissibility in etching and reduce the amount of grinding even in the case of etching. It is another object of the present invention to provide a double-side grinding method and apparatus for preventing cracking of a silicon wafer.

The present invention is a method for manufacturing a silicon wafer including a slicing step of slicing a silicon single crystal rod to produce a silicon wafer and a simultaneous two-sided grinding step of simultaneously grinding the front and back surfaces of the silicon wafer.

Further, in the above-described two-sided simultaneous grinding process, the silicon wafer is sandwiched between the upper grindstone and the lower grindstone of the double-side grinding apparatus, and when the front and back surfaces of the silicon wafer are grinded at the same time, Thereby supplying the grinding liquid.

In the double-sided simultaneous grinding process of the present invention, the temperature of the front and back surfaces of the silicon wafer is controlled.

Further, in the present invention, the silicon wafer is etched by the double-sided simultaneous grinding step to remove grinding damage, and the both surfaces of the silicon wafer are polished.

The present invention relates to a two-side grinding means for simultaneously grinding the top and bottom surfaces of a silicon wafer by sandwiching a silicon wafer between a top side grindstone and a bottom side grindstone, and a temperature control means for controlling the temperature of the front and back surfaces of the silicon wafer Which is an apparatus for producing a silicon wafer.

The temperature control means in the present invention controls the temperature by supplying the grinding liquid to the entire area of the front and back surfaces of the silicon wafer during grinding by the double-side grinding means.

Further, in the present invention,

A water pan formed by inner circumferential surfaces of the upper grindstone and the lower grindstone;

A grinding fluid passageway for allowing the grinding fluid to flow out from the respective grinding surfaces formed on the upper grindstone and the lower grindstone,

And grinding liquid supply means for supplying the grinding liquid to the water pan and the grinding liquid passage.

Further, in the double-side grinding means of the present invention,

An upper grinding wheel and a lower grinding wheel which are horizontally arranged in parallel with each other and which face each other as a grinding surface and which grind the top and bottom surfaces of the silicon wafer,

Relative movement means for relatively moving the upper grindstone and the silicon wafer relative to each other in a horizontal plane and relatively moving the lower grindstone and the silicon wafer in a horizontal plane,

And a pressing step for pressing the upper grindstone against the silicon wafer arranged on the lower grindstone.

Further, in the present invention, the silicon wafer is held by a carrier having outer teeth, and the upper and lower grindstones have openings at respective central portions thereof,

Wherein the relative movement means comprises:

A sun gear installed in the opening so as to engage with the outer teeth of the carrier,

A ring-shaped inner gear provided outside the upper grindstone and the lower grindstone so as to engage with the outer teeth of the carrier, for rotating and rotating the carrier around the sun gear,

And a drive mechanism for rotating the sun gear and the ring-shaped inner gear.

The present invention further includes a pair of upper and lower spacers for supporting the upper and lower surfaces of the end portion of the carrier on the side of the sun gear.

The operation of the present invention will be described below.

It is possible to obtain a silicon wafer having a higher flatness than the silicon wafer after the lapping process because the lapping is not performed. As a result, the etching amount of the silicon wafer is reduced as compared with that of the wafer. It is also possible to reduce the irregularities of the etched surface in this case as compared with the case of performing the lapping. It is also possible to use a small polishing amount in the polishing in the subsequent step.

Further, when the present invention is compared with the case of polishing by one side surface, unevenness transferred to the slice surface is not left on the wafer surface. Therefore, etching can be performed without lapping the wafer after grinding. In addition, since only about 1/10 of the damages caused by the lapping process are not damaged, the amount of etching off is reduced, and deterioration of the flatness due to etching is remarkably prevented.

The feature of double-sided simultaneous polishing is that it is not necessary to place the reference surface for processing a silicon wafer, which is an elastic body, on the material (silicon wafer) side. The reference surface of the grinding may be said to be composed of an active virtual surface (effective acting surface) of the grinding surface (normal surface) of the apparatus side. However, it depends on the rigidity of the material. Let us examine each result using a model in which the surface shape of the silicon wafer is expressed by a sinusoidal curve.

As shown in Fig. 8 (A), there are concavities and convexities on the surfaces of the sliced silicon wafers 30, and these concavities and convexities are "thick" as shown in Figs. 8 (B) and 8 Ingredient " and " sinuous ingredient ". In addition, the serpentine component was the middle line of the wafer front and rear surfaces.

As shown in Fig. 8 (F), when the silicon wafer 30 of Fig. 8 (D) is processed from one side to make the thickness uniform (see Fig. 8E) A surface is created (this is called a warrior).

In addition, when the both surfaces of the silicon wafer are pressed and processed simultaneously on both surfaces (see FIG. 8 (G)), the irregularities of the thick component are removed by machining on both sides of the thick part (see FIG. 8 (H) , And since the silicon wafer is an elastic body, when the processing pressure is released after processing, there is a fear that the wobbling component is left as shown in Fig. 8 (I).

As described above, according to the manufacturing method of a silicon wafer of the present invention, a silicon wafer with high parallelism and high flatness can be manufactured by double-side grinding. At this time, the temperature rise of the upper and lower side grindstones is prevented, and the grinding amount is made uniform over the entire area of the silicon wafer, so that the entire surface of the silicon wafer can be formed flat and warped. Then, after the double-side grinding, etching is performed to remove grinding damage, and one side is mirror-polished to produce a one-side polished silicon wafer. In addition, a double-side polished silicon wafer can be produced by performing both-side simultaneous polishing on the front and back surfaces of the wafer after double-side grinding.

Since the damaged layer of the silicon wafer after double-side grinding is reduced, the damaged layer can be removed even by chemical mechanical polishing with a slow processing speed, and the grinding damage is removed by performing half polishing on the back surface or simultaneous polishing on both the front and back surfaces. A double-side ground silicon wafer can be produced economically.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the entire construction of a double-side grinding apparatus according to an embodiment of the present invention, showing a state in which an upper grindstone is retracted to a raised position, and FIG. 2 is a plan view of a double-side grinding apparatus according to an embodiment of the present invention. 3 is a perspective view showing a main part of a double-side grinding apparatus according to an embodiment of the present invention, Fig. 4 is a double-side grinding according to an embodiment of the present invention. Fig. FIG. 5 is a longitudinal sectional view showing a main part of a double-side grinding apparatus according to an embodiment of the present invention. FIG.

The both surfaces of the silicon wafer 1 held by the carrier 14 are simultaneously grasped by the upper grinding wheel 13 and the lower grinding wheel 12 Respectively. The upper grindstone 13 is rotationally driven around the axis and the lower grindstone 12 is also rotationally driven about its axis.

A lower table drive shaft 5 extending in the vertical direction is rotatably supported on the apparatus main body 3 through a bearing 16. A lower end portion 5a having a smaller diameter of the lower table drive shaft 5 is provided with a pulley-mounted portion integrally mounted on a coaxial shaft, not shown in the figure. The lower table drive shaft 5 can be rotated about its axis by rotating the rotation of the drive motor not shown in the figure through the belt (not shown) on the pulley. The lower table drive shaft 5 is rotatably supported with a sun gear drive shaft 4 having a sun gear 12A at its upper end. The sun gear drive shaft 4 extends in the vertical direction and the lower end portion has a pulley mounting portion in which a pulley not shown in the drawing is integrally mounted on the coaxial shaft. (Not shown in the drawings), the sun gear drive shaft 4 can be rotated around the axis.

A drive shaft 25 having a gear 26 for rotating a ring-shaped inner gear 17 (internal gear) 17, which will be described later, is rotatably supported on the apparatus main body 3. The driving shaft 25 is also rotated about its axis by a driving motor not shown in the figure. A drive motor is constituted by a drive motor or a drive motor for rotating the sun gear drive shaft 4. A disk-shaped mount (lower table) 11 is fixed on the lower table drive shaft 5 via a disk-like spacer member 24. A disk-shaped lower grindstone 12, which will be described later, Is fixed.

Reference numeral 2 denotes an upper table and this upper table 2 is supported in a horizontal state on a rod 9a of a driving means (for example, a cylinder) 9 fixed to the apparatus main body 3 . A disk-shaped upper grindstone 13 is horizontally attached to the lower surface of the upper table 2 via a connecting member 7 and an upper grindstone spacer member 6. The disc-shaped upper grindstone spacer member 6 integral with the full grindstone 13 is rotatably supported with respect to the upper table 2. The outer grindstone spacer member 6 is provided with the outer grindstone 6a, Respectively. When the rod 9a of the cylinder 9 is inserted, the upper grindstone 13 can be raised (in the state of FIG. 1). When the rod 9a is projected, the upper grindstone 13 is lowered, 12 and the silicon wafer 1 can be pressed (state of FIG. 2). As described above, the upper grindstone 13 is vertically movable by means of the pressure-pressing end (the elevating means by the cylinder 9 in this embodiment). Instead of the lifting means by the cylinder 9, for example, a slide mechanism composed of a rack pinion or the like may be employed.

A drive motor 8 is fixed to the upper table 2. A gear 10 is integrally fixed coaxially to a rotary shaft (output shaft) 8a of the drive motor 8. The gear (10) is engaged with the outer teeth (6a) of the upper grindstone spacer member (6). The rotation of the drive motor 8 can be transmitted to the upper grindstone 13 via the upper grindstone spacer member 6 and the upper grindstone 13 can be rotated around the axis.

A plurality of (three in this example, three) disc-shaped carriers 14 between the sun gear 12A and the ring-shaped inner gear 17 are engaged with outer teeth formed on the outer periphery thereof, And the inner peripheral teeth of the ring-shaped inner peripheral gear 17, respectively. That is, the carrier 14 operates as a planetary gear for the sun gear 12A and the ring-shaped inner gear 17, respectively. Each carrier 14 is provided with a receiving hole 15 capable of accommodating one silicon wafer 1, respectively. Each of these silicon wafers 1 is mounted in the receiving hole 15 of the carrier 14 and each lower surface is provided so as to be slidable on the lower grindstone 12. [ In addition, the thickness of the carrier 14 is smaller than the thickness of the silicon wafer 1. On the upper surface of these silicon wafers 1, the upper grindstone 13 can be slidably joined to each other. The upper grindstone 13 has an opening 13B at the center and the lower grindstone 12 also has the same opening 12B as the opening 13B and the upper and lower grindstones 13, The inner diameter is roughly equivalent. It is a thin plate of spherical graphite cast iron.

As described above, the silicon wafer 1 is opened and held between the upper grindstone 13 and the lower grindstone 12 so that both the front and back surfaces thereof are simultaneously grinded. That is, the silicon wafer 1 is held in a carrier 14 having outer teeth, and the carrier 14 has a receiving hole (circular hole) 15 through which the silicon wafer 1 can be inserted. The outer circumferential teeth of the carrier 14 are engaged with the sun gear 12A and also with the inner circumferential teeth of the ring-like inner gear 17. The ring-shaped inner gear 17 is arranged so as to surround the lower grindstone 12 with a larger outer diameter than that of the lower grindstone 12. In this example, three carriers 14 for holding one silicon wafer 1 are provided, and three silicon wafers 1 are simultaneously subjected to both-side grinding. However, the present invention is not limited to this. A plurality of radial grooves and circumferential grooves obtained in the radial direction and the circumferential direction are formed on the grinding surface (lower surface) of the upper grindstone 13 and the grinding surface (upper surface) of the lower grindstone 12.

Next, the detailed configuration of the main part of the double-side grinding apparatus will be described.

As shown in Figs. 1 to 5, reference numeral 12 denotes a lower grinding wheel on which a silicon wafer 1 as a grinding target is disposed. The lower grindstone 12 is arranged and fixed to the mount 11 as a disk having a circular opening (center hole) 12B formed at the center thereof. Reference numeral 21a denotes a spacer supporting member disposed on the lower table 5 and the spacer supporting member 21a is inserted into the sun gear driving shaft 4. [ Further, the spacer supporting member 21a does not rotate together with the lower table drive shaft 5.

Reference numeral 12C denotes a lower spacer disposed on the spacer supporting member 21. An end of each carrier 4 on the side of the sun gear 12A is disposed on the lower spacer 12C. An upper spacer 13A having substantially the same shape as that of the upper spacer 13A is disposed on the lower spacer 12C and the lower spacer 12C and the sun gear 12A side. In addition, the spacers 12C and 13A are rotatably fitted in the sun gear 12A. The carrier 14 is bent by the pressure of the grinding fluid (refer to the thick arrows in FIGS. 2 and 5) supplied from above the opening 13B of the upper grindstone 12 by the above- Do not. The weight of the upper booster pager 13A is of a size that does not interfere with the movement of each of the carriers 14 in the meteoric orbit described later.

The upper grindstone 13 is movable up and down as described above, and the silicon wafer 1 held by the carrier 14 can be pressed down by the lower grindstone 12 under a predetermined load. As shown by the arrows in FIG. 2, a grinding liquid supply means (not shown) for supplying a grinding liquid (for example, pure water) from above the upper grindstone 13 toward the opening 13B Not installed).

The respective inner peripheral surfaces of the upper grindstone spacer member 6, the upper grindstone 13, the lower grindstone 12, the mount 11 and the spacer member 24 and the upper surface of the lower table drive shaft 5, And the space surrounded by the outer circumferential surfaces of the upper and lower spacers 13A and 12C is a water pan (space) W having a predetermined volume.

Next, the detailed structure of the upper grindstone spacer member 6 and the upper and lower grindstones 13, 12 will be described focusing on the grinding fluid passages.

First, as shown in Fig. 1, a plurality of (two only shown) through holes 18 penetrating in the vertical direction are formed in the upper grindstone spacer member 6, (In this example, at regular intervals) in the direction of the arrow. As shown in FIGS. 1 to 6, a ring-shaped annular groove 19 is formed on the inner circumferential side of the upper surface of the upper legs 13. The position where the annular groove 19 is formed overlaps with the position of the through hole 18 of the upper grindstone spacer member 6. [ One end of the upper grindstone 13 communicates with the annular groove 19 and a plurality of grindstones extending in the radial direction of the upper grindstone 13 in the radial direction of the upper grindstone 13 Are formed in the radial groove 20. The other end of the radial groove 20 is communicated with a through hole 21 for vertically passing the upper grindstone 13.

On the other hand, as shown in FIGS. 1 and 7, a plurality of radiation grooves 23 extending radially from the inner wall of the lower grindstone 12 are formed. Each of the radial grooves 23 extends from the inner circumferential end of the lower grindstone 12 to a substantially intermediate portion in the radial direction and a plurality of through holes (22) are communicated with each other.

In FIGS. 2 and 5, the arrows in bold lines indicate the state of the flow of the grinding liquid. The grinding liquid supplied to the water pan W from the upper side of the upper grindstone 13 is supplied from the outer peripheral side of the silicon wafer 1 between the upper and lower grindstones 13 and 12 to the upper and lower surfaces thereof, The grinding liquid supplied by the centrifugal force due to the rotation in the horizontal plane of the lower grindstones 13, 12 is supplied to the outer periphery side of the upper and lower grindstones 13, 12. By doing so, the grinding liquid is supplied over the entire upper and lower surfaces of the silicon wafer 1.

The grinding liquid is supplied to the plurality of through holes 18 of the upper grindstone spacer member 6. The supplied grinding liquid is supplied to the annular groove 19 of the upper grindstone 13, And is supplied to the approximately central portion of the upper surface of the silicon wafer 1 through the hole 21. The grinding liquid supplied to the water pan W is also supplied to the substantially central portion of the lower surface of the silicon wafer 1 through the radiation groove 23 and the through hole 22 of the lower grindstone 12. This makes it possible to reliably control the temperature of the entire silicon wafer 1.

In order to grind both the front and back surfaces of the silicon wafer using the double-side grinding apparatus, the silicon wafer 1 after the slicing is inserted into the receiving hole 15 of the carrier 14 and the upper and lower grinding wheels 13, And the upper grindstone 13 and the lower grindstone 12 are rotated in a horizontal plane at a predetermined speed, respectively. At this time, the upper grindstone 13 is lowered by a predetermined amount (for example, 100 占 퐉) while pressing the silicon wafer 1 under a predetermined load. At this time, the grinding liquid is always supplied from the upper grindstone 13 to control and manage the temperature of the silicon wafer 1 to a constant value (for example, 25 캜). This grinding liquid is always fed from the water pan W to the central portion of the silicon wafer 1 through the grooves (the radial grooves and the circumferential grooves) of the respective grinding surfaces. Therefore, the temperature of the central portion of the silicon wafer 1 can be constantly controlled. As is clear from the above description, the temperature control means is constituted by the grinding liquid supply means (nozzle or the like), the grinding liquid passage, and the water pan W.

The silicon wafer 1 is first placed in the receiving hole 15 of the carrier 14 and placed on the lower grindstone 12 so that the upper grindstone 13 is separated from each silicon wafer 1 As shown in Fig. Then, when the sun gear 12A and the ring-shaped inner peripheral gear 17 are rotated in the direction of the arrow in FIG. 4 while supplying the grinding liquid to the upper and lower surfaces of the silicon wafer 1 as described above, Is automatically rotated in the arrow direction in the fourth direction. Accordingly, the silicon wafer 1 grinds the lower surface of the lower grindstone 12 while grinding the lower surface of the lower grindstone 12 by the upper surface (grinding surface) of the lower grindstone 12 while grinding the lower surface thereof. The upper surface of the silicon wafer 1 is rubbed on the lower surface (abrasive surface) of the upper grindstone 13 by grinding by rotating the upper grindstone 13 in a direction opposite to the lower grindstone 12.

As described above, the relative movement means is constituted by the sun gear 12A, the sun gear drive shaft 4, the ring-shaped inner gear 17, the drive motor 8, and the like. Further, the relative movement means, the upper grindstone 13 and the lower grindstone 12 constitute both-side grinding means.

9 (A) and 9 (B) are flowcharts for explaining the manufacturing process and the process of the present invention, respectively, according to the prior art.

In the conventional production of a silicon wafer, first, a silicon single crystal ingot is sliced, and the sliced silicon wafer is chamfered (step S2). The plurality of silicon wafers thus obtained are distinguished according to the scattering of the thickness in large and small (batch configuration, step S3). The reason for such arrangement is that the more the thickness is, the shorter the lapping time to be described later. The silicon wafers discriminated with respect to this thickness are lapped at the same time for each thickness (step S4) and cleaned after lap (step S5). This cleaning is a powerful cleaning for removing a large amount of iron and iron ions generated from wear of upper and lower grinding wheels of spherical graphite cast iron during lapping and lapping from a silicon wafer. Then, the silicon wafer is cleaned with an alkaline surfactant (step S6), and the damage caused by the chamfering is partially removed by etching (Chemical Corner Rounding). After that, etching is performed after cleaning.

On the other hand, in the present invention, as shown in FIG. 9 (B), for example, slicing by wire (step S10) and chamfering after stepping (step S11) Step S12). Since both sides of the silicon wafer are grinded at the same time in the double-side simultaneous grinding, the parallelism of both surfaces can be obtained in a short time, thereby eliminating the necessity of arrangement.

It is not necessary to perform cleaning immediately after the above-described wrapping because no wrapping agent is used. Then, after cleaning (step S13), CCR and cleaning are performed, and the back surface of the silicon wafer is half-polished again, or both surfaces are simultaneously subjected to chemical mechanical polishing to remove the grinding damage layer. This double-sided simultaneous chemical mechanical polishing is carried out by a pair of upper and lower plates that respectively hold a polishing cloth in place of the upper and lower grinding wheels of the above-mentioned both-side simultaneous grinding apparatus. It is possible to process the silicon wafer with high precision by performing the back side half polishing or the both side simultaneous polishing without passing through the conventional lapping and etching processes.

In addition to the manufacturing method not involving the etching step, the step after the cleaning (step S13) may be the same as the conventional method.

10 shows the relationship between the lowering speed of the upper grinding wheel 13 (lowering amount of the upper grinding wheel / machining time) and the load at that time. The rotational speeds of the lower grindstone 12 and the upper grindstone 13 at this time are 77 rpm and 51 rpm, respectively, for example. When the load is small (for example, 120 + 30 kgf = O), it takes time to grind a predetermined amount. If the load is intermediate (165 + 30 kgf = Δ) and the load is large (210 + 30 kgf = □), the grinding time is appropriate. However, when the load applied is larger than the case where the load is large, cracks are generated in the silicon wafer under such conditions as the rotational speed and the like.

11 shows a result of double-side grinding by changing the rotational speeds of the upper grindstone 13 and the lower grindstone 12 by setting the load constant (165 + 30 kgf) by using this apparatus. The lower grindstone 12 and the upper grindstone 13 were rotated at 45 rpm and 28 rpm, respectively, and 60 rpm, 38 rpm, and? Were 77 rpm and 77 rpm, respectively, for the rotational speeds of the lower grindstone 12 and the upper grindstone 13, 51 rpm, and? Indicates the case of 87 rpm and 57 rpm, respectively. From the viewpoints of the time required for grinding and the crack,? And? Indicate good results.

As described above, according to the double-side grinding according to the present embodiment, a silicon wafer having a high flatness compared to the silicon wafer after the lapping can be obtained. As shown in Fig. 12, for example, TTV can be set to 0.66 mu m (measured value by capacitance type surface flatness meter = ADE). As a result, the etching-off amount is reduced compared with a wafer to be wafers, and can be set to 2 탆, for example. In this case, the irregularities of the etched surface can be made smaller as compared with the case of performing the lapping process, for example, 0.1 mu m. Further, in the later polishing step, the polishing amount can be as small as about 2 mu m, and SFQD can be easily achieved to about 0.1 mu m.

Further, as compared with the case where the present invention is ground for each one side, unevenness transferred to the sliced surface is not left on the surface of the silicon wafer. Therefore, it is possible to perform the etching without lapping the silicon wafer after the cutting. In addition. Only one tenth of the damage amount due to the lapping process is left, so that the amount of etching off is reduced and the deterioration of the flatness due to etching is remarkably prevented. In this embodiment, there is an effect that the cutting powder on the cutting surface can be removed by the grinding liquid.

INDUSTRIAL APPLICABILITY The present invention is configured as described above, and therefore, the following effects are exhibited.

The manufacturing method according to the present invention can manufacture a silicon wafer having a high flatness required for manufacturing a highly integrated device of 1 G bit or more in comparison with the case of raing machining and can reduce the amount of etching off, Can be reduced. Further, the polishing amount in the polishing step is at least. Cleaning after lapping becomes unnecessary. Compared with one-side grinding, it is not necessary to perform cleaning and lapping.

It is also possible to prevent the temperature rise of the silicon wafer and uniformly manage it, and to make the thickness and residual damage of the silicon wafer uniform throughout the whole area, thereby forming the entire surface flat and reducing warping.

Since the silicon wafer after double-side grinding has few damaged layers, it is possible to remove the damaged layer even if the machining speed is slow, so that the grinding damage is removed by half polishing the back surface or simultaneous polishing on both the front and back surfaces, A silicon wafer can be manufactured economically.

The manufacturing apparatus of the present invention can easily carry out the above manufacturing method and also can rotate the upper grindstone and the lower grinding wheel in accordance with the action of the relative movement means and further perform the planetary motion of the carrier for holding the silicon wafer, It is possible not only to uniformly grind both surfaces but also to miniaturize the grinding apparatus.

The temperature control means can supply the grinding liquid from the inner circumferential side of the upper grindstone and the lower grindstone toward the silicon wafer, the cross-sectional side and the central portion from the grinding surfaces of the upper grindstone and the lower grindstone, respectively, And is supplied to the entire upper and lower surfaces of the silicon wafer by the centrifugal force of the lower grindstone. Thus, it is possible to reliably control the temperature over the entire surface of the silicon wafer, and it is advantageous in that warpage is reduced because the residual damage on both surfaces becomes uniform.

Further, it is possible to prevent deformation of the carrier caused by the pressure of the grinding liquid by fitting the end portion of the carrier on the side of the sun gear by the upper and lower spacers.

FIG. 1 is an overall configuration diagram of a double-side grinding apparatus according to an embodiment of the present invention, showing a state in which an upper grindstone is in a raised position.

FIG. 2 is an overall configuration diagram of a both-side grinding apparatus according to an embodiment of the present invention, showing a state in which the upper grindstone is in a lowered position.

3 is a perspective view showing a main part of a double-side grinding apparatus according to an embodiment of the present invention.

FIG. 4 is a plan view showing a main part of a double-side grinding apparatus according to an embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing a main part of a double-side grinding apparatus according to an embodiment of the present invention.

6 is a plan view of the upper grinding wheel.

7 is a plan view of the lower grinding wheel.

8 (A) to (I) are diagrams for explaining the improvement of the flatness of the silicon wafer.

9 (A) and 9 (B) are flowcharts for explaining the conventional art and the manufacturing art of the present invention, respectively.

FIG. 10 is a graph showing the results of double-side grinding in accordance with an embodiment of the present invention. FIG.

FIG. 11 is a graph showing the results of double-side grinding in accordance with an embodiment of the present invention. FIG.

FIG. 12 is a schematic view showing a surface state resulting from double-side grinding in accordance with an embodiment of the present invention. FIG.

FIG. 13 is a schematic view similar to FIG. 5 showing a surface state of a conventional silicon wafer.

14 (A) to 14 (C) are schematic diagrams showing the surface state of the wafer when the silicon wafer is vacuum-adsorbed and its one side is delayed.

FIG. 15 is a schematic view of a silicon wafer which is tapered; FIG.

Claims (4)

  1. And a temperature control means for controlling the temperature of the front and back surfaces of the silicon wafer at the time of the double-side grinding, wherein the temperature control means controls the temperature of the front and back surfaces of the silicon wafer,
    The temperature control means controls the temperature by supplying a grinding liquid to the entire front and back surfaces of the silicon wafer being ground by the double-side grinding means,
    Wherein the temperature control means comprises a water pan formed by inner circumferential surfaces of the upper grindstone and the lower grindstone, a grinding fluid passageway formed in the upper grindstone and the lower grindstone for respectively discharging the grinding fluid from the respective grinding surfaces, A water pan, and a grinding liquid supply means for supplying a grinding liquid to the grinding liquid passage.
  2. The polishing apparatus according to claim 1, wherein the double-
    An upper grindstone and a lower grindstone which are horizontally arranged in parallel with each other and which face each other as a grinding surface and which grind the top and bottom surfaces of the silicon wafer,
    Relative movement means for relatively moving the upper grindstone and the silicon wafer relative to each other in a horizontal plane and relatively moving the lower grindstone and the silicon wafer in a horizontal plane,
    And pressing means for pressing the upper grindstone against the silicon wafer placed on the lower grindstone.
  3. 3. The method of claim 2,
    Wherein the silicon wafer is held by a carrier having outer teeth, and the upper and lower grindstones have openings at respective central portions thereof,
    Wherein the relative movement means comprises:
    A sun gear installed in the opening so as to engage with the outer teeth of the carrier,
    A ring-shaped inner gear provided on the outer side of the lower grindstone for revolving and rotating the carrier around the sun gear;
    And a drive mechanism for rotating the ring gear and the sun gear and a drive mechanism for rotating the ring-shaped inner gear.
  4. The method of claim 3,
    And a pair of upper and lower spacers for sandwiching and supporting the upper and lower surfaces of the end portion of the carrier on the side of the sun gear.
KR10-1996-0019031A 1995-07-03 1996-05-31 Method and apparatus for manufacturing silicon wafer KR100457718B1 (en)

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JP19117195 1995-07-03
JP95-191171 1995-07-03
JP96-004415 1996-01-12
JP441596 1996-01-12
JP8978496A JP3923107B2 (en) 1995-07-03 1996-04-11 Silicon wafer manufacturing method and apparatus
JP96-089784 1996-04-11

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Families Citing this family (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3620554B2 (en) * 1996-03-25 2005-02-16 信越半導体株式会社 Semiconductor wafer manufacturing method
JP2002346918A (en) * 2001-05-29 2002-12-04 Speedfam Co Ltd Both surface polishing device
DE10132504C1 (en) * 2001-07-05 2002-10-10 Wacker Siltronic Halbleitermat Method for simultaneously polishing both sides of semiconductor wafer mounted on cogwheel between central cogwheel and annulus uses upper and lower polishing wheel
DE10142400B4 (en) * 2001-08-30 2009-09-03 Siltronic Ag Improved local flatness semiconductor wafer and method of making the same
FR2850966B1 (en) 2003-02-10 2005-03-18 Rhodia Polyamide Intermediates Process for producing dinitril compounds
FR2854891B1 (en) 2003-05-12 2006-07-07 Rhodia Polyamide Intermediates Process for preparing dinitriles
CN1301184C (en) * 2003-12-16 2007-02-21 汪开庆 Optical grinding machine and method for processing sapphire crystal substrate for semiconductor use
EP1948591A1 (en) 2005-10-18 2008-07-30 INVISTA Technologies S.à.r.l. Process of making 3-aminopentanenitrile
KR20080104315A (en) 2006-03-17 2008-12-02 인비스타 테크놀러지스 에스.에이.알.엘 Method for the purification of triorganophosphites by treatment with a basic additive
DE102006062872B4 (en) * 2006-07-13 2012-06-14 Peter Wolters Gmbh Simultaneous double-side grinding providing method for semiconductor wafer, involves machining semiconductor wafers in material-removing fashion between rotating upper working disk and lower working disk
DE102006062871B4 (en) * 2006-07-13 2012-06-21 Peter Wolters Gmbh Simultaneous double-side grinding providing method for semiconductor wafer, involves machining semiconductor wafers in material-removing fashion between rotating upper working disk and lower working disk
US7919646B2 (en) 2006-07-14 2011-04-05 Invista North America S.A R.L. Hydrocyanation of 2-pentenenitrile
DE102007056628B4 (en) 2007-03-19 2019-03-14 Siltronic Ag Method and apparatus for simultaneously grinding a plurality of semiconductor wafers
EP2146930A2 (en) 2007-05-14 2010-01-27 INVISTA Technologies S.à.r.l. High efficiency reactor and process
CN101952004B (en) 2007-06-13 2015-08-12 因温斯特技术公司 Improve the method for adiponitrile quality
CN101918356B (en) 2008-01-15 2013-09-25 因温斯特技术公司 Hydrocyanation of pentenenitriles
CN101910119B (en) 2008-01-15 2013-05-29 因温斯特技术公司 Process for making and refining 3-pentenenitrile, and for refining 2-methyl-3-butenenitrile
JP4780142B2 (en) * 2008-05-22 2011-09-28 信越半導体株式会社 Wafer manufacturing method
JP2009302409A (en) * 2008-06-16 2009-12-24 Sumco Corp Method of manufacturing semiconductor wafer
JP5600867B2 (en) * 2008-06-16 2014-10-08 株式会社Sumco Manufacturing method of semiconductor wafer
US8247621B2 (en) 2008-10-14 2012-08-21 Invista North America S.A.R.L. Process for making 2-secondary-alkyl-4,5-di-(normal-alkyl)phenols
DE102009025242B4 (en) * 2009-06-17 2013-05-23 Siltronic Ag Method for two-sided chemical grinding of a semiconductor wafer
CN102471218B (en) 2009-08-07 2014-11-05 因温斯特技术公司 Hydrogenation and esterification to form diesters
CN101708593B (en) * 2009-12-08 2013-01-09 中国电子科技集团公司第四十五研究所 Chemical-mechanical polishing mandrel driving device
CN101875181B (en) * 2010-05-31 2012-02-22 青岛理工大学 Crisp and hard material grinding machine
CN101972983B (en) * 2010-08-11 2013-01-09 中国电子科技集团公司第四十五研究所 Chemically mechanical polishing mandrel device
CN102172885B (en) * 2011-01-31 2013-05-15 北京通美晶体技术有限公司 Substrate polishing device and polished substrate thereof
CN102179734A (en) * 2011-03-14 2011-09-14 刘晓明 Super-hard blade passivation polishing machine
CN102229093B (en) * 2011-07-01 2013-09-18 中国电子科技集团公司第四十五研究所 Lifting and pressing mechanism applied to wafer polishing equipment
DE102011089570A1 (en) 2011-12-22 2013-06-27 Siltronic Ag Guide cage for grinding both sides of at least one disc-shaped workpiece between two rotating working wheels of a grinding device, method for producing the guide cage and method for simultaneous two-sided grinding of disc-shaped workpieces using the guide cage
CN103123865B (en) * 2013-02-26 2015-05-27 宁波韵升股份有限公司 Magnetic product processing method and automatic sorting device
CN104669105B (en) * 2013-11-26 2017-12-29 浙江汇锋塑胶科技有限公司 A kind of two sides Ginding process of sapphire touch panel
CN103817572A (en) * 2014-02-18 2014-05-28 河南机电高等专科学校 Repairing device for clutch friction steel sheets
CN103847032B (en) * 2014-03-20 2016-01-06 德清晶辉光电科技有限公司 The production technology of the ultra-thin quartz wafer of a kind of major diameter
JP2017071040A (en) * 2015-10-09 2017-04-13 株式会社Sumco Carrier ring, grinding device, and grinding method
CN106425857A (en) * 2016-11-18 2017-02-22 南京华东电子信息科技股份有限公司 Novel polishing fixing jig for small and medium single liquid crystal display panels
CN107543837B (en) * 2017-08-25 2020-02-21 郑州磨料磨具磨削研究所有限公司 Method for detecting damaged layer of silicon wafer after grinding wheel fine grinding
CN108544329A (en) * 2018-04-09 2018-09-18 中国工程物理研究院材料研究所 A kind of surface polishing and grinding apparatus and its application

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59107854A (en) * 1982-12-08 1984-06-22 Hitachi Ltd Both surfaces simultaneous grinding method of wafer
JPS59169758A (en) * 1983-03-15 1984-09-25 Toshiba Corp Grinding device for wafer
JPS6384860A (en) * 1986-09-26 1988-04-15 Hitachi Ltd Surface polishing device
JP2555000B2 (en) * 1989-01-18 1996-11-20 鐘紡株式会社 The polishing method of hard and brittle materials
CA2012878C (en) * 1989-03-24 1995-09-12 Masanori Nishiguchi Apparatus for grinding semiconductor wafer
JPH0740565B2 (en) * 1991-04-05 1995-05-01 不二越機械工業株式会社 Double-sided simultaneous grinding method and apparatus of the wafer
JPH0667070A (en) * 1992-08-24 1994-03-11 Furukawa Electric Co Ltd:The Semiconductor laser module
JP2839801B2 (en) * 1992-09-18 1998-12-16 三菱マテリアルシリコン株式会社 Method of manufacturing a wafer
JP2722975B2 (en) * 1992-11-19 1998-03-09 住友金属工業株式会社 Cutting method according to a multi-wire saw
JP3047670B2 (en) * 1993-04-08 2000-05-29 トヨタ自動車株式会社 Control device for an electric vehicle engine generator

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DE19626396A1 (en) 1997-01-16
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DE19626396B4 (en) 2006-12-07
JPH09248740A (en) 1997-09-22
CN1096108C (en) 2002-12-11
TW303488B (en) 1997-04-21
KR970008384A (en) 1997-02-24

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