US3855738A

US3855738A - Crystal indexing fixture

Info

Publication number: US3855738A
Application number: US00305018A
Authority: US
Inventors: R Guggenheim; F Liucci
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1972-11-09
Filing date: 1972-11-09
Publication date: 1974-12-24
Anticipated expiration: 1991-12-24
Also published as: DE2355339B2; DE2355339A1; GB1383738A; IT991302B; JPS4984783A; FR2206699A5; DE2355339C3; CA1000308A

Abstract

A crystal boule indexing fixture, the fixture comprising a frame including a pair of spaced apart, axially extending bores having parallel axes, and a pair of rods extending through the bores. A cover is hingedly connected to the frame through a hinge pin having an axis parallel to the axis of the bores, the cover being movable between a first position overlying a portion of the rods to press a crystal boule against the rods and a second position to increase the spacing of the cover from the rods so as to permit entrance to and egress from the fixture of such a boule. A lever projects from the cover and is biased so as to maintain the cover in its first position. Means are also provided to engage the lever to override the biased cover to lift the cover into the second position to facilitate entry and removal of the crystal boule.

Description

Guggenheim Sr. et a1.

[451 Dec. 24, 1974 CRYSTAL INDEXING FIXTURE [75] Inventors: Robert Clifton Guggenheim Sr.,

Poughkeepsie; Frank Victor Liucci, Wappingers Falls, both of NY.

[73] Assignee: international Business Machines Corporation, Armonk, NY.

22 Filed: Nov. 9, 1972 21 Appl. No.2 305,018

[56] References Cited UNITED STATES PATENTS 394,793 12/1888 Stoecklin 1. 269/196 2,114,978 4/1938 Horger et al 82/38 2,382,257 8/1945 Ramsay 51/3 2,416,703 3/1947 51/217 A X 2,421,349 5/1947 ..51/l65.77 X 2,960,978 11/1960 125/13 R 3,039,235 6/1962 Heinrich 51/73 R 3,085,370 4/1963 Dietz 51/92 R 3,154,990 11/1964 Woods 83/414 3,168,893 2/1965 Johnson 125/13 R 3,300,205 l/1967 Fitzpatrick 2 69/236 X 3,302,285 2/1967 Mann 3,432,973 3/1969 Heinrich 3,662,733 5/1972 Okamoto 51/73 R X OTHER PUBLICATIONS American Machinist, May 12, 1952, p. 179, Cam Clamp.

Primary ExaminerAl Lawrence Smith Assistant ExaminerMarc R. Davidson Attorney, Agent, or Firm-William 1. Dick [57] ABSTRACT A crystal boule indexing fixture, the fixture comprising a frame including a pair of spaced apart, axially extending bores having parallel axes, and a pair of rods extending through the bores. A cover is hingedly connected to the frame through a hinge pin having an axis parallel to the axis of the bores, the cover being movable between a first position overlying a portion of the rods to press a crystal boule against the rods and a second position to increase the spacing of the cover from the rods so as to permit entrance to and egress from the fixture of such a boule. A lever projects from the cover and is biased so as to maintain the cover in its first position. Means are also provided to engage the lever to override the biased cover to lift the cover into the second position to facilitate entry and removal of the crystal boule.

15 Claims, 3 Drawing Figures CRYSTAL INDEXING FIXTURE The purpose of this abstract is to enable the public and the Patent Office to determine rapidly the subject matter of the technical disclosure of the application. This abstract is neither intended to define the invention of the application nor is it intended to be limiting as to the scope thereof.

SUMMARY OF THE INVENTION AND STATE OF THE PRIOR ART The present invention relates to an indexing fixture, and more particularly relates to a crystal boule indexing fixture to be utilized on or in conjunction with crystal slicing saws.

Saws for cutting crystal boules, such as boules of silicon and germanium, have been employed in the electronics industry for a number of years. One of the principal saws employed is of the type manufactured by Hamco Machine and Electronics Corporation, and is typified in US. Pat. No. 3,039,235 issued on June 19, 1962 to the aforementioned assignee. In these saws which may be categorized as hole saws, the saw blade takes the form of a thin flat annulus which is provided with a cutting edge at the inner periphery of the annulus. The crystal is moved against the edge at a variable rate of movement to cut a thin slice from the crystal, and then the crystal is returned to the central portion of the annular cutting device, indexed downwardly a small increment, and the cycle is repeated.

While there have been numerous holders employed for carrying the boule so that it may be properly indexed into the hole for jutting purposes, and while the machine has been modified so as to permit proper orientation of the crystal so that the cut or slice formed by the cutting operation will be along the proper crystallographic plane, such holding fixtures have had, in the past, several disadvantages. For the most part the disadvantage has been the time required in adjusting the crystal so that it is properly held in the holder while feeding the crystal into the saw blade. Additionally, inasmuch as the crystal must be fed into the central opening of the annular cutting blade, the holders have of necessity required a certain degree of freedom to permit sliding of the boule downwardly into the annulus while resisting the torque created by the moving blade as well as the torque created by the movement of the holder against the blade. Thus the boule must be held firmly so as to prevent radial shift thereof upon contacting the inner periphery (cutting edge) of the annulus while still allowing a degree of freedom so that it may be indexed through the holder for subsequent slicing cuts.

Additionally, after a number of slices have been formed by cutting the crystal boule with the slicing blade or device, it is sometimes beneficial to dress the blade with, for example, a silicon carbide dressing stick. With present apparatus, it is necessary to apply a special fixture and jig to apply the dressing stick to the blade to thereby dress the blade. This, of course, takes additional time and reduces the machine throughput per work shift.

In view of the above it is a principal object of the present invention to provide a novel crystal boule indexing fixture.

Another object of the present invention is to provide a crystal boule indexing fixture which is readily adaptable to existing saws such as crystal slicing hole saws.

Still another object of the present invention is to provide a crystal boule indexing fixture which will hold the crystal rigidly to prevent lateral or radial displacement thereof as the crystal is being cut by the cutting blade, but which will permit indexing of the crystal longitudinally of the fixture so as to permit repetitive placement of the crystal in a predetermined position for cutting slices of semiconductor crystal of uniform thickness.

Yet another object of the present invention is to provide a crystal indexing fixture which may be easily oriented so as to permit cutting of the crystal along any desired crystallographic plane.

Yet another object of the present invention is to provide a crystal boule indexing fixture in which a dressing stick may easily be mounted to facilitate ease of dressing of the cutting edge of the blade of the machine upon which the fixture is mounted.

Still another object of the present invention is to provide a fixture having a cover thereon to clamp the crystal in a predetermined orientation relative to the machine while permitting ease of application of the cover to the boule and firm grasping of the boule while permitting the boule to be easily indexed.

Other objects and a more complete understanding of the invention may be had by referring to the following specification and claims taken in conjunction with the accompanying drawings in which:

FIG. 1 is a fragmentary front elevational view illustrating a crystal boule indexing fixture constructed in accordance with the present invention;

FIG. 2 is a fragmentary side elevational view of the fixture illustrated in FIG. 1; and

HG. 3 is a fragmentary bottom view of the apparatus illustrated in FIGS. 1 and 2.

Referring now to the drawings, and more specifically FIG. 1 thereof, a crystal boule indexing fixture 10, constructed in accordance with the present invention, is illustrated therein. As shown in the drawing, the fixture 10 includes a frame 11 having a central body portion 12 and projecting

flange portions

13 and 14 extending from the body 12. The

flange portions

13 and 14 include a pair of arcuate slots 13A and 14A respectively, which with

bolts

15 and 16 serve to position the fixture 10 at a desired angle (in the plane of the paper) relative to a vertical axis, on the frame 17 of a cutting machine.

In accordance with the invention means are provided on the fixture to effect a three point location of a crystal boule 20 to grasp the boule firmly so as to prevent tortional motion or movement of the boule as cutting is effected while permitting indexing of the boule for subsequent cuts as by a saw blade 18 rotating in the machine 19. To this end, and referring now to FIGS. 2 and 3, the body 12 of the frame 11 includes upper and

lower pedestal portions

21 and 22 respectively each having a pair of spaced apart axially extending

bores

23 and 24 therein, the bores having parallel axes and housing therein

upstanding rods

25 and 26 respectively. As shown best in FIG. 3, each of the

pedestals

21 and 22 includes a recessed portion 27 which permits the circumference or surface of the rods to project outwardly away from the pedestals so as to permit engagement thereof by the surface of the boule 20. To prevent longitudinal displacement of the

rods

25 and 26 in the

bores

23 and 24, set screws 25A and 26A are utilized to grasp the rods to the body of the frame 11.

In order to clamp the boule against the rods while permitting axial or longitudinal displacement of the boule therein, a quick release cover 30 is hingedly connected to the frame and movable between a first position overlying a portion of the rods to press a crystal boule against the rods and a second position to increase the spacing of the cover from the rods to permit entrance to and egress from the fixture of a crystal boule. To this end, and as illustrated in FIGS. 2 and 3, the cover 30 is generally arcuate in shape and subtends an angle of approximately 90 so that its terminal end 31 substantially overlies a plane drawn perpendicular to a line joining the axes of the rods and 26. In this manner the terminal end may capture the crystal boule 20 between the cover and the

rods

25 and 26.

In most instances, to facilitate and maintain alignment of the crystal while permitting proper indexing thereof parallel to the axes of the rods, as well as during the cutting operation, anti-torque means are provided on the cover to mate with means on the boule to inhibit rotation thereof. To this end, a glass filled phenolic key 32 is bonded to the surface of the boule as with a semirigid epoxy, such as an Emerson Cummings EC-45 resin. The key registers, mates or coopreates with a keyway 33 in the cover adjacent the terminal end 31 thereof.

As illustrated best in FIGS. 2 and 3, the

pedestals

21 and 22 include a projecting end portion having hinge pin 34 receiving

apertures

29A and 29B therein, in the illustrated instance the apertures 298 in each of the

pedestals

21 and 22 connecting, through the hinge pin 34 and bored bosses 35 and 36, the cover 30. A handle 37 may be employed to facilitate grasping of the cover In order to facilitate proper clamping of the cover on the boule 20, quick acting clamp means are provided to facilitate moving of the cover between a first position overlying the rods and pressing a crystal boule between the cover and the rods and a second position wherein the cover is lifted away from the rods so as to facilitate loading of the fixture with a boule. To this end, and referring now to FIGS. 1, 2 and 3, the cover includes a projecting lever 40 having a bored hole or aperture 41 therein to receive a post 42 which is secured as by threads to the flange 13. Intermediate the flange and the lever is biasing means, in the illustrated instance a heavy spring 43 which tends to apply force about the hinge pin 34 against the lever and therefore tends to maintain the cover 30 in a position pressing the boule against the

rods

25 and 26. To facilitate opening of the cover, against the bias of the spring 43, the post 42 is connected to a sleeve 44 which fits intermediate a bifurcated cam 45 which is connected to actuating means, in the present instance a handle 46. Inasmuch as the sleeve is rigidly secured to the pin or post 42, while the bifurcated cam 45 is connected to the sleeve by a shaft 47 which is free to rotate in the sleeve 44, motion of the handle downwardly, in the illustrated instance away from the cover, causes the lobe 45A of the cam the engage the upper surface of the lever effecting rotation of the cover 30 about the hinge pin 34 and elevation of the cover into the second position.

To prevent inadvertent movement of the cover when the boule is in position intermediate the cover and the

rods

25 and 26, the sleeve 44 is provided with a groove 48 therein, while the bifurcated cam includes a bored hole 49 therein which permits the entry to and egress therefrom of a locking pin 50.

In the event a larger crystal boule 20 is desired to be sliced, the hinge pin 34 may be removed from the apertures 29B and moved upwardly to the apertures 29A, thereby accommodating an increased diameter crystal boule. As is evident to maintain at least the same closing pressure of the cover against the boule a different spring may be employed or the existing spring may be shimmed to accommodate the increase in spacing between the flange and the lower surface of the lever 40. Additionally, a different cam and post may be neces sary, or if the threaded end is of sufficient length, the post may simple be unscrewed from the flange 13 as sufiicient distance to accommodate the spacing between the

holes

29A and 29B.

Often during cutting or slicing the operator will notice that the product being cut is receiving some surface defects usually due to an increase in roughness of the blade, indicating that the blade requires dressing or replacement. In such an event, with existing machines, it is necessary to dismount the crystal indexing fixture, or in the alternative to at least place it out of use and in a position so as not to interfere with the dressing operation. With the fixture of the present invention, it is a simple matter to place the dressing tool on one of the flanges, for example the flange 14. To this end, a dressing fixture 51 may be employed, the fixture including a block 52 connected to the flange 14 and dovetailed to receive a slide 53 thereon to which is connected a dressing stick 54 as by a ring clamp or the like 55. The slide may have a mating dovetail as at 56 and include a rack gear which mates with a drive pinion 57 which permits elevation and depression of the dressing stick 54 towards and away from the blade 18 shown schematically in FIG. 1. The dressing stick may be composed of any suitable dressing material, for example silicon carbide, and may easily be adjusted as to the ring clamp 55 merely by loosening the ring clamp and moving the stick downwardly as the stick is used.

Any typical conventional drive means may be employed to index the crystal boule 20 downwardly to permit slicing of the boule. For example, as shown in FIG. 1, a drive means 65 may be employed including a lead screw 66 or the like which is driven in a stepping fashion as by a stepping motor or an air drive, the lower end of the lead screw 66 abutting the crystal so as to effect axial displacement thereof along the guide rods between the cover and the guide rods.

Thus the present invention provides a simple and yet novel crystal boule indexing fixture particularly adapted to existing saws.

Although the invention has been described with a certain degree off particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts and the mode of operation may be made without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. A crystal boule indexing fixture, said fixture comprising: a frame including a pair of spaced apart, axially extending bores having parallel axes; a pair of rods extending through said bores, a cover hingedly connected to said frame and movable between a first position overlying a portion of said rods to press a crystal boule against said rods and a second position to increase the spacing of said cover from said rods; a lever projecting from said cover and means biasing said lever to maintain said cover in said first position; and anti-torque means on said cover to mate with means on a crystal boule to inhibit rotation thereof, said anti-torque means comprising one of a key and key-way, and said means on a crystal boule comprising the other of said key and key-way; and means to engage said lever to over-ride said biasing means to lift said cover into said second position.

2. A crystal boule indexing fixture, said fixture comprising: a frame including a pair of spaced apart, axially extending bores having parallel axes; a pair of rods extending through said bores, a cover hingedly connected to said frame and movable between a first position overlying a portion of said rods to press a crystal boule against said rods and a second position to increase the spacing of said cover from said rods; said frame including a body portion and projecting flanges, and means defining arcuate slots in each of said flanges to permit adjustment of said body portion in a vertical plane; a lever projecting from said cover and means biasing said lever to maintain said cover in said first position; and anti-torque means on said cover to mate with means on a crystal boule to inhibit rotation thereof, and means to engage said lever to over-ride said biasing means to lift said cover into said second position.

3. A crystal boule indexing fixture, said fixture comprising: a frame including a pair of spaced apart, axially extending bores having parallel axes; a pair of rods extending through said bores, a cover hingedly cnnected to said frame and movable between a first position overlying a portion of said rods to press a crystal boule against said rods and a second position to increase the spacing of said cover from said rods; a lever projecting from said cover and means biasing said lever to maintain said cover in said first position; and anti-torque means on said cover to mate with means on a crystal boule to inhibit rotation thereof, and means to engage said lever to over-ride said biasing means to lift said cover into said second position, and a holder for a dressing stick; and means to adjustably position said holder in a direction substantially parallel to said rods.

4. A crystal boule indexing fixture, said fixture comprising: a frame including a pair of spaced apart, axially extending bores having parallel axes; a pair of rods extending through said bores, a cover hingedly connected to said frame and movable between a first position overlying a portion of said rods to press a crystal boule against said rods and a second position to increase the spacing of said cover from said rods; a lever projecting from said cover and means biasing said lever to maintain said cover in said first position; and anti-torque means on said cover to mate with means on a crystal boule to inhibit rotation thereof, and means to engage said lever to over-ride said biasing means to lift said cover into said second position, and including drive means; and means for coupling said drive means to a crystal boule held intermediate said cover and rods to displace said boule in a direction parallel to said rods and therealong.

5. A crystal boule indexing fixture, said fixture comprising: a frame including a pair of spaced apart, axially extending bores having parallel axes; a pair of rods extending through said bores, a cover hingedly connected to said frame and movable between a first position overlying a portion of said rods to press a crystal boule against said rods and a second position to increase the spacing of said cover from said rods; a lever projecting from said cover and means biasing said lever to maintain said cover in said first position; and anti-torque means on said cover to mate with means on a crystal boule to inhibit rotation thereof, and means to engage said lever to over-ride said biasing means to lift said cover into said second position; a hinge pin in said cover and means carrying said pin on said frame; and alternate hinge pin carrying means on said frame to displace said cover further from said rods than when said cover is in said first position.

6. A crystal boule indexing fixture, said fixture comprising: a frame including a pair of spaced apart, axially extending bores having parallel axes; a pair of rods extending through said bores, a cover hingedly connected to said frame and movable between a first position overlying a portion of said rods to press a crystal boule against said rods and a second position to increase the spacing of said cover from said rods; a lever projecting from said cover and means biasing said lever to maintain said cover in said first position; including cam means bearing against said lever, and actuating means connected to said cam means to effect motion to said lever against biasing means; and anti-torque means on said cover to mate with means on a crystal boule to inhibit rotation thereof, and means to engage said lever to over-ride said biasing means to lift said cover into said second position.

7. A crystal boule indexing fixture in accordance with claim 6 wherein said biasing means comprises a spring.

8. A crystal boule indexing fixture in accordance with claim 7 including locking means for maintaining said actuating lever in a predetermined position.

9. A crystal boule indexing fixture comprising: a frame including a body portion and a pair of projecting flanges, means for adjustably mounting said flanges to a surface; a pair of spaced apart, parallel, axially extending bores in said body portion; a pair of rods extending through said bores, and a recess in said body exposing a portion of the surface of said rods; a cover hingedly connected to said frame and moveable between a first position overlying said exposed portion of said rods to press a crystal boule against said rods and a second position to increase the spacing of said cover from said rods; means to bias said cover to maintain said cover in said first position, and means to overcome said bias to effect movement of said cover into said second position.

10. A crystal boule indexing fixture in accordance with claim 9 including means in said cover for gripping a crystal to inhibit rotation thereof.

11. A crystal boule indexing fixture in accordance with claim 10 including a key way in said cover, said key way adapted for cooperating with a key on a crystal.

12. A crystal boule indexing fixture in accordance with claim 9 including a holder mounted on one of said flanges, said holder including means to position a dressing stick thereon, and means to adjustably position said holder in a direction substantially parallel to said rods.

means to efiect motion to said lever against said biasing means.

15. A crystal boule indexing fixture in accordance with claim 14 including means for locking said actuating means in a predetermined position.

Claims

13. A crystal boule indexing fixture in accordance with claim 9 including a lever projecting from said cover, and said biasing means being in operative engagement with said lever.

14. A crystal boule indexing fixture in accordance with claim 13 including cam means bearing against said lever, and actuating means connected to said cam means to effect motion to said lever against said biasing means.