Abstract:
There is described an apparatus for producing a single crystal ingot capable of stably manufacturing a single crystal ingot by means of the Czochralski method, without being affected by influence of variation in extension of wires or an offset in points clamped by a clamping member. The clamping member is engaged with an engagement step formed in a single crystal which is being pulled by the CZ method, and the single crystal is pulled. The single crystal ingot manufacturing apparatus is provided with a flexible mechanism for absorbing variation in extension of the wires, in intermediate portions of the wires. Variation in extension of the wires is eliminated by means of the flexible mechanism, thereby retaining the single crystal in an upright position. Further, a sacrifice member which deforms so as to conform to the circumference of the engagement step is interposed between the clamping member and the engagement step, thereby preventing occurrence of cracking or deformation in the single crystal.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for producing a single crystal by pulling a single crystal from source melt by means of the Czochralski method (hereinafter referred to as the “CZ method”), and especially, relates to an apparatus for producing a single crystal by means of the CZ method, suitable for pulling a heavy single crystal having a diameter of greater than 300 mm. 
     2. Description of the Related Art 
     A single crystal silicon is generally produced through use of the CZ method. According to the CZ method, polycrystalline silicon is charged intò a quartz crucible disposed within a single crystal pulling apparatus. The polycrystalline silicon is heated and dissolved into a melt by means of a heater disposed around the quartz crucible. Subsequently, a seed crystal attached to a seed chuck is immersed into the melt. The seed holder is pulled while the seed chuck and the quartz crucible are rotated in a single direction or in opposite directions, to thereby grow a single crystal to a predetermined diameter and length. Under the CZ method, a neck having a diameter of about 3-4 mm must be formed in a lower portion of the seed crystal by means of the Dash technique in order toeliminate dislocations from the seed crystal. However, in response to a recent tendency for improving the efficiency of production of a semiconductor device, a demand exists for manufacture of a single crystal having a large diameter by means of the CZ method. In association with an increase in the diameter of a single crystal, the weight of the single crystal increases. Single crystal manufacturing apparatus have been suggested (in, for example, Japanese Patent Application Laid-Open Nos. Sho-62-288191 and 63-252991) , in which a constricted engagement step is formed in a single crystal remaining in a pulled state so that the heavy single crystal can withstand pulling action. 
     FIG. 18 shows an example of a conventional single crystal manufacturing apparatus provided with a clamping body. A pull head  2 , which is rotatably provided at the upper end of the manufacturing apparatus, has provided therein a crystal pull wire take-up device  3  and a plurality of wire take-up devices  51  for raising/lowering a clamping member  50 . A seed chuck  6  holding a seed crystal  5  is fixed to the lower end of a crystal pull wire  4  hanging the crystal pull wire take-up device  3  and extends to the center of a furnace. Melt  7  is stored in a quartz crucible which is disposed within an unillustrated main chamberso as to be able to rotate and move vertically. 
     The clamping member  50  is provided with a plurality of claws  53  provided in a pivotable manner at the lower end of a cylindrical clamping body  52  (the claws  53  are pivotable within a vertical plane and within a predetermined range of angle). The claws  53  are engaged with an engagement step engagement stepla. By means of this arrangement, a single crystal  1  can be pulled when the wire take-up devices  51  takes up wires  54 . 
     However, the single crystal manufacturing apparatus having the foregoing configuration often encounters a problem of occurrence of an inclination in the single crystal  1  for reasons of an inclination in the gripping member  50  stemming from a variation in extension of the wires  54  (FIG. 19) or for reasons of an offset in points clamped by the gripping member  50  (FIG.  20 ). If the single crystal  1  is held in a slanted attitude and rotated while the axis of the single crystal  1  is tilted, runouts arising in a growth boundary is amplified, thereby adversely affecting the growth of the single crystal  1  and inducing poly-crystallization of the single crystal  1  arises. 
     Furthermore, in the event that the clamping member  50  clamps the single crystal  1  at the engagement step  1   a  with the aid of jaw-shaped claws  53 , the weight of the single crystal  1  will focus on several contact points. This will induce cracking or distortion to the single crystal  1 . On the worst occasion, the single crystal  1  could be destroyed. 
     SUMMARY OF THE INVENTION 
     The object of this invention is to provide an apparatus for producing a single crystal. In the process of pulling a single crystal by the CZ method, the device according to this invention conducts a clamping member to engage with a engagement step formed in the single crystal remaining in a pulled state and is capable of steadily pulling a single crystal without any influence caused by a variation in extension of the wires or dislocating of clamping body. 
     Another object of this invention is to prevent cracking or distortion of the single crystal when the clamping body clamps the reduced and engagement step formed in the single crystal. 
     To achieve the above-mentioned objects, this invention is characterized in that: a flexible mechanism (also referred to as a free-pivoting mechanism), having a first flexible member capable of tilting even though the single crystal is being clamped by the clamping body, is provided. By this arrangement, the single crystal can be kept in the verticle attitude by absorbing a variation in extension of the wires through the flexible mechanism. 
     Furthermore, this invention is characterized in that: a flexible mechanism, having a second flexible member capable of tilting even that the clamping body is being suspended by a plurality of long members, is provided. By this arrangement, the single crystal can be held in the vertical attitude by absorbing an offset in points clamped by a clamping body induced by inconsistency between the contacting points on the engagement step. 
     Furthermore, as to the flexible mechanism having a first flexible member and the flexible mechanism having a second flexible member, installing either one or both of them simultaneously on the apparatus for producing a single crystal is acceptable. 
     Furthermore, it is also acceptable to install the flexible mechanism on the apparatus for producing a single crystal either separately or integrally with the clamping body. Furthermore, it has been known that the flexible mechanism is irrelevant to the kinds of single crystals; therefore this invention is not only suitable to devices for producing a single crystal but also suitable to all kinds of single crystal manufacturing devices only if the CZ method is employed. 
     According to another aspect of the present invention, in a process in which the engagement step through use of the clamping body, a sacrifice member whose shape is fit to the profile of the circumference of the engagement step is interposed between the clamping body and the engagement step, thereby preventing cracking or distortion of the single crystal. 
     Specifically, in the clamping body of the apparatus for producing a single crystal according to this invention, the portion in contact with the engagement step during the operation of clamping the engagement step with the aid of the clamping body is composed of a sacrifice member, which deforms to fit the outer periphery of the engagement step. By this arrangement, cracking or distortion of the single crystal can be prevented. 
     Due to the existence of the sacrifice member, the sacrifice member deforms it to fit the outer periphery of the engagement step so as to increase the contact area during the operation of clamping the engagement step with the aid of the clamping body. Therefore, the force applied from the clamping body toward the engagement step is distributed; and cracking or distortion of the single crystal, which inevitably causes the breakage of the single crystal, can be prevented. 
     As described above, the distinction of this invention is that the force exerted between the clamping body and the engagement step is distributed through the deformation of the sacrifice member. If the sacrifice member is made of elastic-deformation material, then it could be repeatedly used. If the sacrifice member is made of plastic-deformation material, then it is necessary to change the sacrifice member regularly before each operation. 
     Furthermore, the deformation of the sacrifice member takes place to fit the shape of the outer periphery of the engagement step. However, it is preferred that the deformation of the sacrifice member is not only match with the macroscopic shape of the outer periphery of the engagement step but also match with the microscopic shape such as tiny unevenness on the outer periphery of the engagement step. 
     Furthermore, it is possible to determine the structure and the material of the sacrifice member according to this invention. Therefore, this invention is adapted to all kinds of single crystals produced by pulling processes. However, in the event of pulling silicon single crystals, it is preferable to choose stainless pipes packed with wires as sacrifice members because they could prevent micro-cracks. 
     Furthermore, no matter the single crystal to be pulled is a silicon or not, if heat-endurance of sacrifice members is considered to be important, it is preferable to fill tubes up with carbon material so as to fabricate the sacrifice members. The carbon material could be such as: carbon fibers, graphite material, or carbon-fiber-reinforced carbon. However, from the viewpoint that the sacrifice members have to deform a pertinent amount, carbon-fiber-reinforced carbon is the best choice. Moreover, if carbon-fiber-reinforced carbon is used, metal tubes (for example, stainless tubes) can prevent separation of laminated layers in carbon-fiber-reinforced carbon, which is induced by deformation pressure. 
     Basic Principle of the Flexible Mechanism 
     According to the flexible mechanism of this invention, the clamping body can tilt around a single crystal remaining in a pulled state in any direction (essentially, an arbitrary angle within  3600 ) during clamping operation. 
     An example for this flexible mechanism is shown in FIGS. 21A,  21 B, and  21 C. In this flexible mechanism, the wires  54  engaging with the wire take-up devices  51  and the wires  54 ′ engaging with the clamping body  50  are respectively engaging with a plate body  55  with a  900  angular displacement. In this case, the joints  54 p of the wires  54  and the plate body  55  and the joints  54 ′p of the wires  54 ′ and the plate body  55  are fabricated in a manner that the wires  54 ,  54 ′ are capable of freely rotating with respect to the plate body  55 . 
     Therefore, if either wires  54 ′ is pulled downward alone when the wires  54  are fixed, then the plate body  55  will be pivotally supported by the wires  54  and tilt around the X-axis. 
     In contrast, if the respective wires  54  are pulled upward while the wires  54 ′ are fixed, the plate body  55  is supported by the wires  54 ′ and is pivoted about the Y-axis. 
     Accordingly, when the flexible mechanism shown in FIGS. 21A,  21 B, and  21 C is interposed between the wire take-up devices  51  and the clamping body  50  and a variation in extension of the wires  54  occurs; the wires  54 ′ remain unmoved and the plate body  55  solely tilts around the Y-axis. Therefore, a variation in extension of the wires  54  will not shift to the clamping body  50 , and the single crystal remaining in a pulled state will not tilt. On the other hand, when the clamping body  50  dislodges its clamping points, the plate body  55  tilts around the X-axis to absorb the dislocation and the wires  54  remain unmoved. Consequently, the single crystal can be held in its clamped attitude and can be driven to rotate freely. Accordingly, runout of the single crystal axis will not arise. Furthermore, even though a variation in extension of the wires  54  and dislocation of the clamping points of the clamping body  50  occur simultaneously, both of them will be absorbed and nullified by the flexible mechanism shown in FIGS. 21A,  21 B, and  21 C. 
     As described above, both of the impertinent situations occurred respectively above and below the flexible mechanism can be nullified by only disposing the flexible mechanism therebetween. Therefore, single crystals can be steadily produced without any influence induced by a variation in extension of the wires  54  or dislocation of the clamping points of the clamping body  50 . 
     Moreover, in the above flexible mechanism, the plate body  55  was used as the flexible member capable of tilting during clamping the single crystal by the clamping body  50  or suspending the clamping body  50  by long members. The flexible member plays double roles of a first flexible member and a second flexible member. The first flexible member is capable of tilting during clamping the single crystal by the clamping body  50  and the second flexible member is capable of tilting during suspending the clamping body  50  by long members. 
     An Alternative Example for the Flexible Mechanism 
     As shown in FIGS. 22A,  22 B, and  22 C (wherein members having the same functions as those shown in FIGS. 21A,  21 B, and  21 C are designated identical numerals), two plies of the flexible mechanism shown in FIGS. 21A,  21 B, and  21 C are linked together through one pair of connecting wires  54 ″. The upper plate body  55  and the lower plate body  55 ′ are capable of respectively tilting around the Y-axis and the Y′-axis alone. Therefore, the dimensional discrepancy induced respectively above and below the flexible mechanisms can be nullified by the flexible mechanisms. Accordingly, single crystals can be steadily produced without any influence induced by a variation in extension of wires and dislocation of the clamping points of the clamping body. 
     Furthermore, in the flexible mechanism shown in FIGS. 22A,  22 B, and  22 C, the plate bodies  55  and  55 ′ are flexible members. The upper plate body  55  is the first flexible member capable of tilting in the state of clamping the single crystal by the clamping body  50 , and the lower plate body  55 ′ is the second flexible member capable of tilting while the clamping body  50  is suspended by long members. 
     Furthermore, in the flexible mechanism shown in FIGS. 22A,  22 B, and  22 C, it is also acceptable to install the clamping body  50  directly on the lower plate body  55 ′ without disposing the clamping body  50  at the lower portions of the wires  54 ′. 
     The flexible mechanism shown in FIGS. 23A,  23 B,  23 C,  23 D and  23 E (wherein members having the same functions as those shown in FIGS. 21A,  21 B,  21 C,  22 A,  22 B, and  22 C are designated identical numerals) is composed of pulleys  57  and  57 ′ instead of the plate body  55  capable of tilting. As shown in FIG. 23A, the wire  54  is passing around the wheel of the moving pulley  57 , and the wire  54 ′ is installed on the axis of the moving pulley  57  in a sliding manner (namely, the wire  54 ′ is unable to be wrapped up by the axis of the moving pulley  57 ). By this arrangement, when a variation in extension of the wires  54  occurs, the moving pulley  57  rotates by only the magnitude of a variation in extension, whereby the variation in extension is thus nullified. On the other hand, the wire  54 ′ is passing around the wheel of the pulley  57 ′ and the wire  54  is installed on the axis of the pulley  57 ′ in a manner capable of sliding. Therefore, basing on the same rule, the offset in the points clamped by the clamping body could also be nullified. 
     Accordingly, as in the case of the previous example shown in FIGS. 21A,  21 B, and  21 C, impertinent situations (dimensional discrepancy) respectively occurred above and below the flexible mechanism can be nullified by the flexible mechanism. Furthermore, as shown in FIGS. 23C and 23D, when one flexible mechanism  56  is composed by connecting the moving pulley  57  and the pulley  57 ′ with connecting wires  54 ″, there can be yielded substantially the same working-effects as those yielded by the example shown in FIGS. 22A,  22 B, and  22 C can be obtained. 
     In addition, when the dimensional discrepancy induced by length dispersion among plural long members and the dimensional discrepancy induced by an offset in the points clamped by the clamping body on the engagement step are absorbed by a flexible mechanism composed by one set of pulleys, twisting of the wires  54 ″ can be prevented by using axis holding members  54 ″′ to disrupt the coaxiality between the set of the rotating axes. 
     Beside the previous examples, the flexible mechanism shown in FIGS. 24A,  24 B and  24 C (wherein members having the same functions as those shown in FIGS. 21A to  23 E are designated identical numerals) is composed of two plate bodies  55 ,  55 ′ and a spring body  58  disposed therebetween. By this arrangement, a variation in extension of the wires  54  can be absorbed by the elastic deformation of the spring body  58 , and the same functions and effects as those of the previous examples can be obtained. Furthermore, according to this example, if movements are constrained within a small scope, two plate bodies  55 ,  55 ′ can respectively sway freely in any direction (namely, an arbitrary angle within 360°) alone. 
     Moreover, in the flexible mechanism shown in FIGS. 24A,  24 B and  24 C, the same as the flexible mechanism shown in FIGS. 22A,  22 B, and  22 C, the first flexible member is the upper plate body  55  and the second flexible member is the lower plate body  55 ′. In addition, in the flexible mechanism shown in FIGS. 24A,  24 B, and  24 C, it is also acceptable to install the clamping body  50  directly on the lower plate body  55 ′ without disposing the clamping body  50  at the lower portions of the wires  54 ′. 
     Moreover, as shown in FIGS. 25A and 25B (wherein members having the same functions as those shown in FIGS. 21A to  24 C are assigned identical numerals), the flexible mechanism can be constructed by an infinity sliding ball-spline structure. Namely, in this example, wires  54 ′ are connecting with an outer shell  59 ″, and wires  54 ′ are connecting with an inner shell  59 ′. Plural balls  59  are packed within an annular rail formed between the outer shell  59 ″ and the inner shell  59 ′. The outer shell  59 ″ and the inner shell  59 ′ are respectively capable of tilting alone through rolling of the balls. 
     Therefore, when a variation in extension of the wires  54  occurs, the outer shell  59 ″ tilts in a direction in favor of nullifying the variation in extension. Thus, during employing the flexible mechanism shown in FIGS. 25A and 25B, single crystals could be steadily pulled without any influence caused by a variation in extension of the wires or an offset in the points clamped by the clamping body. 
     Furthermore, in this example, it is needless to rotate the outer shell  59 ″ through the wires  54 . Namely, when the wires  54  coupled with the single crystal  1  is rotated through the rotating of the wire  4 ; the inner shell  59 ′ will be driven to rotate. However, invalid rotations of the balls  59  take place, and it is also satisfactory to keep the outer shell  59 ″ unmoved. 
     !In the flexible mechanism shown in FIG. 25, the first flexible member corresponds to the outer shell  59 ″, and the second flexible member corresponds to the inner shell  59 ′. Similarly, even in the flexible mechanism shown in FIGS. 25A and 25B, the clamping member  50  may be directly attached to the inner shell  59 ′ rather than being provided at a lower portion of the wires  54 ′. 
     The following are descriptions of scopes to be claimed, which are based on the above-described principles and bring forth the intended effects. 
     (1) An apparatus for producing a single crystal, which forms a engagement step in the single crystal remaining in a pulled state by the CZ method and suspends the single crystal with the aid of the engagement step, comprising: a clamping body used for clamping the engagement step, and at least two contact points in contact with the engagement step being provided; a plurality of long members for suspending the clamping body; and a flexible mechanism having a first flexible member capable of tilting even that the single crystal is being clamped by the clamping body and/or a second flexible member capable of tilting even that the clamping body is being suspended by the long members. 
     In this case, “wire” is a typical example for “long member”, and “wire take-up device” is a typical example for “driving section”. The major aspect of this invention resides in nullifying impertinent situations induced by a variation in extension of long members and inclination of the clamping body. Therefore, a long member is not limited to a wire, and any member may be used, so long as the member has a predetermined length and can pull a single crystal which would be finally formed into an ingot. 
     Furthermore, as described in the following embodiments, in general, a plurality of long members (mostly two) is concurrently used. However, it is also satisfactory to use only one long member (see FIG.  26 ). 
     Because any flexible mechanism having the above-described functions could be utilized in this invention, flexible mechanisms not shown in FIGS. 21A to  25 B having the same or equivalent functions as those of the above-described should be contained in the concept of the flexible mechanism according to this invention. 
     Furthermore, the subject of this invention resides in nullifying impertinent situations (dimensional discrepancy) within a mechanism and obviously is irrelevant to what kind of melted material from which the single crystal is pulled. Therefore, the “single crystal” is not limited to silicon single crystals. 
     Furthermore, it is acceptable to install the flexible mechanism by coupling it at the middle portion of the long member, or alternatively to form it integrally with the clamping body at one end of the long member. 
     Because the first flexible member is capable of tilting even that the single crystal is being clamped, the first flexible member tilts and absorbs length dispersion occurred between plural long members (see FIG. 19) when it took place. 
     Furthermore, since the second flexible member is capable of tiling even that the clamping body is being suspended by long members, the second flexible member tilts and absorbs the offset in the points clamped by the clamping body occurred on the engagement step (see FIG. 20) when an offset occurs. 
     As described above, the first flexible member is employed for nullifying the dimensional discrepancy occurred between plural long members and the second flexible member is employed for nullifying the dimensional discrepancy induced by an offset in the points clamped by the clamping body. Therefore, if both of them are installed in a flexible mechanism, then both the dimensional discrepancies occurred between plural long members and the dimensional discrepancy induced by an offset in the points clamped by the clamping body can be absorbed by the flexible mechanism. 
     (2) An apparatus for producing a single crystal as described in (1) characterized in that: the flexible member is capable of tilting in any direction within 3600. 
     (3) An apparatus for producing a single crystal as described in (1) or (2) characterized in that: the flexible mechanism includes an elastic member whose elastic deformation enables the tilting of l the flexible member. 
     (4) An apparatus for producing a single crystal as described in (1) or (2) characterized in that: the flexible mechanism includes a sliding member whose sliding movement enables the tilting of the flexible member. 
     A typical example for the device described in above (3) is shown in FIGS. 24A to  24 C, and typical examples for the device described in above (4) are shown in FIGS. 6,  7 ,  14 ,  15 ,  16 ,  17 ,  25 A and  25 B. Furthermore, these examples meet to the requirements established in above (2). 
     (5) An apparatus for producing a single crystal as described in (1) or (2) characterized in that: the flexible mechanism includes a seesaw member capable of tilting around a preset axis, and the flexible member is driven to tilt by the seesaw member. 
     (6) An apparatus for producing a single crystal as described in (1) or (2) characterized in that: the flexible mechanism is composed of a plurality of seesaw members each of which is capable of tilting around a preset axis, and each axis is not coaxial with others. 
     The “preset axes” of the flexible mechanism are determined by the structure of the flexible mechanism employed. In the flexible mechanism shown in FIGS. 21A to  22 C, the “preset axes” are X-axis and Y-axis shown therein. 
     Furthermore, it is also acceptable to combine the seesaw member described in (5) or (6) with the sliding member described in (4) so as to construct a flexible mechanism (for example, those shown in FIGS. 6,  7 ,  14 ,  15 ,  16 , and  17 ). On this occasion, it is preferred to dispose a sliding structure restraining balls at the joint portion between long members and coupling portions. By this, the long members could engage with the flexible mechanism in a manner capable of rotating without any restraint (see FIGS.  6  and  7 ). 
     (7) An apparatus for producing a single crystal as described in (6) characterized in that: the sum of the plural seesaw members is two. 
     (8) An apparatus for producing a single crystal as described in (7) characterized in that: the axes of the two seesaw members are perpendicular to each other. 
     (9) An apparatus for producing a single crystal as described in any one of (1) to (8) characterized in that: the sum of the long members is at least two. 
     (10) An apparatus for producing a single crystal as described in (9) characterized in that: the sum of the long members is two. 
     (11) An apparatus for producing a single crystal, which forms a engagement step in the single crystal remaining in a pulled state by the CZ method and suspends the single crystal with the aid of the engagement step, comprising: a clamping body used for clamping the engagement step, and at least two contact points in contact with the engagement step being provided; a plurality of long members for suspending the clamping body; and a flexible mechanism used for absorbing the dimensional discrepancy induced by length dispersion among the plural long members and the dimensional discrepancy induced by an offset in the points clamped by the clamping body on the engagement step and the flexible mechanism being provided with plural pulleys whose rotational axes are not coaxial with one another. 
     A typical example in conformity with the concept of (5) is shown in FIGS. 21A,  21 B and  21 C. In this case, the plate body  55  is equivalent to the seesaw member. Typical examples for the above (7) and (8) are shown in FIGS. 22A,  22 B and  22 C. In this case, the plate bodies  55  and  55 ′ are equivalent to the seesaw members. 
     (12) an apparatus for producing a single crystal, the device forming a engagement step in the single crystal remaining in a pulled state by the CZ method and suspending the single crystal with the aid of the engagement step, the device comprising a clamping body used for clamping the engagement step and a plurality of long members for suspending the clamping body; characterized in that: during clamping the engagement step, the contact portion of the clamping body is constructed by a sacrifice member capable of deforming to fit the outer periphery of the engagement step. 
     (13) An apparatus for producing a single crystal as described in (12) characterized in that: the sacrifice member is exchangeable and capable of being affixed or detached freely. 
     (14) An apparatus for producing a single crystal as described in (13) characterized in that: the sacrifice member is provided with plural protrusion elements extending toward the engagement step. 
     (15) An apparatus for producing a single crystal as described in (13) characterized in that: the sacrifice member is provided with a sacrifice space that gets narrower during deforming of the sacrifice member. 
     (16) An apparatus for producing a single crystal as described in (15) characterized in that: the sacrifice space is a hole divergent in a direction substantially perpendicular to the deformation direction of the sacrifice member. 
     (17) An apparatus for producing a single crystal as described in (13) characterized in that: the sacrifice member is constructed by a bar-shaped body. 
     (18) An apparatus for producing a single crystal as described in (17) characterized in that: the bar-shaped body is consisted of a metal tube and carbon material packed within the metal tube. 
     (19) An apparatus for producing a single crystal as described in (18) characterized in that: the metal tube is a stainless tube and the carbon material is carbon fibers, graphite material, or carbon-fiber-reinforced carbon. 
     The carbon-fiber-reinforced carbon is a compound material whose carbon matrix is reinforced by carbon fibers. This carbon-fiber-reinforced carbon maintains a high strength sufficient for constructing structural members even at a temperature above 1500° C. It can be bought by the trade name “C-C composite” and it has been employed on space shuttles these days. 
     As described in the subsequent (20), it is also acceptable to appropriately combine those described in (1)-(11) with those described in (12)-(19). 
     (20) An apparatus for producing a single crystal, which forming a engagement step in the single crystal remaining in a pulled state by the CZ method and suspending the single crystal with the aid of the engagement step, which comprising: a clamping body used for clamping the engagement step, and at least two contact points in contact with the engagement step being provided; a plurality of long members for suspending the clamping body; and a flexible mechanism having a first flexible member capable of tilting even that the single crystal is being clamped by the clamping body and/or a second flexible member capable of tilting even that the clamping body is being suspended by long members; characterized in that: during clamping the engagement step, the contact portion of the clamping body is constructed by a sacrifice member capable of deforming to fit the outer periphery of the engagement step. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings, given by way of illustration only and thus not intended to limit the present invention. 
     FIG. 1 is a schematic illustration showing the concept of the clamping device employed in the device for pulling single crystals according to this invention; 
     FIG. 2 is a perspective view showing the shapes of structure members in an example for establishing an omidirectional tilt center; 
     FIG. 3 is a perspective view showing the assembled omidirectional tilt center shown in FIG. 2; 
     FIG. 4 is a perspective view showing the structure for constructing one axis of an omidirectional tilt center according to another example; 
     FIG. 5 is a cross-sectional view of a clamping device according to the first embodiment of this invention; 
     FIG. 6 is a cross-sectional view of a clamping device according to the second embodiment of this invention; 
     FIG. 7 is a top view of the clamping device shown in FIG. 6; 
     FIG. 8 is a perspective view showing a clamping device for pulling single crystals according to the third embodiment of this invention; 
     FIG. 9 is a side view showing the clamping device shown in FIG. 8, with cross-sectional portions therein; 
     FIG. 10 is a top view showing a coupling frame member according to the third embodiment of this invention; 
     FIG. 11 is a cross-sectional view along line A—A of FIG. 10; 
     FIG. 12 is a top view showing a frame member according to the third embodiment of this invention; 
     FIG. 13 is a cross-sectional view along line B—B of FIG. 12; 
     FIG. 14 is a top view showing a coupling frame member according to the fourth embodiment of this invention; 
     FIG. 15 is a cross-sectional view along line c—c of FIG. 14; 
     FIG. 16 is a top view showing a frame member according to the fourth embodiment of this invention; 
     FIG. 17 is a cross-sectional view along line D—D of FIG. 16; 
     FIG. 18 is an illustration showing functions of a conventional device for pulling single crystals, which is provided with a clamping device; 
     FIG. 19 is an illustration showing the inclined state of a single crystal induced by a variation in extension of wires in a conventional clamping device; 
     FIG. 20 is an illustration showing the state of an inclined single crystal clamped by a conventional clamping device; 
     FIGS. 21A,  21 B, and  21 C are schematic illustrations for explaining the basic principle of this invention, wherein FIG. 21A is a perspective view, FIG. 21B is a side view along X-axis, and FIG. 21C is a side view along Y-axis; 
     FIGS. 22A,  22 B, and  22 C are schematic illustrations for explaining the basic principle in the event of overlapping two flexible mechanisms shown in FIGS. 21A,  21 B, and  21 C, wherein FIG. 22A is a perspective view, FIG. 22B is a side view along X-axis, and FIG. 22C is a side view along Y-axis; 
     FIGS. 23A,  23 B,  23 C,  23 D, and  23 E are schematic illustrations for explaining the basic principle of a flexible mechanism employing pulleys, wherein FIG. 23A is used for explaining the nullification of impertinent situations of upper long members, FIG. 23B is used for explaining the nullification of impertinent situations of lower long members, FIG. 23C is used for explaining the basic principle of a flexible mechanism consisting of two pulleys, and FIG. 23D is a side view of the flexible mechanism shown in FIG. 23C; 
     FIGS. 24A,  24 B, and  24 C are schematic illustrations for explaining the basic principle of a flexible mechanism employing a spring, wherein FIG. 24A is a perspective view, FIG. 24B is a side view along Y-axis, and FIG. 24C is a top view; 
     FIGS. 25A and 25B are schematic illustrations for explaining the basic principle of a flexible mechanism employing an infinity sliding ball-spline, wherein FIG. 25A is a side cross-sectional view and FIG. 25B is a top view; 
     FIG. 26 is a perspective view showing an embodiment having only one long member; 
     FIGS. 27A and 27B are schematic illustrations showing the state of the fifth embodiment according to this invention before applying a load thereon, wherein FIG. 27A is a cross-sectional view along line A—A of FIG. 27B; 
     FIGS. 28A and 28B are schematic illustrations showing the state of the fifth embodiment according to this invention after applying a load thereon, wherein FIG. 28A is a cross-sectional view along line A—A of FIG. 28B; 
     FIGS. 29A,  29 B,  29 C, and  29 D are schematic illustrations showing a variety of alternative examples for the bar-shaped body of the fifth embodiment according to this invention; 
     FIG. 30 is an illustration showing the sixth embodiment according to this invention; 
     FIG. 31 is an illustration showing the seventh embodiment according to this invention; 
     FIGS. 32A and 32B are schematic illustrations showing the state of the eighth embodiment according to this invention before applying a load thereon, wherein FIG. 32A is a cross-sectional view along line A—A of FIG. 32B; 
     FIGS. 33A and 33B are schematic illustrations showing the state of the eighth embodiment according to this invention after applying a load thereon, wherein FIG. 33A is a cross-sectional view along line A—A of FIG. 33B; 
     FIGS. 34A and 34B are schematic illustrations showing the state of the ninth embodiment according to this invention before applying a load thereon, wherein FIG. 34A is a cross-sectional view along line A—A of FIG. 34B; and 
     FIGS. 35A and 35B are schematic illustrations showing the state of the ninth embodiment according to this invention after applying a load thereon, wherein FIG. 35A is a cross-sectional view along line A—A of FIG.  35 B. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following is a description, with reference to the drawings, of embodiments of an apparatus for producing a single crystal according to this invention. 
     FIG. 1 is a schematic illustration showing the concept of a clamping body for pulling a single crystal. A clamping body  10  is vertically moved by a clamping body raising/lowering means (which employs a plurality of wires; for example, three wires  11  in the present embodiment) which vertically moves the clamping body  10  in association with pull of a single crystal. Wire connectors  12  (herein, wires correspond to raising/lowering means) are separated from a clamping member connector  13  (hereinafter referred to as a “retaining section”) to which claws for retaining an engagement step  1   a  of a single crystal  1 . A coupling member  14  is interposed between the wire connectors  12  and the retaining section  13 . The wire connectors  12  of the wires and the retaining section  13  are capable of respectively tilting around two omidirectional tilt centers O 1 , O 2  independently in all directions. The two omidirectional tilt centers O 1 , O 2  are located at the rotation axis Z-Z of the single crystal. Furthermore, the omidirectional tilt center O 1  is substantially located at the geometric center of the engaging points of wires  11 . The omidirectional tilt center O 2  is substantially located at or above the intersecting point G of the plane containing the crystal clamping points of the retaining section  13  and the rotation axis of the crystal. The omidirectional tilt center O 1  has a function of absorbing length dispersion induced by a variation in extension of the wires  11 , and the omidirectional tilt center O 2  has a function of amending the tilting of the single crystal  1  clamped in a tilted attitude. 
     It is not required to arrange engaging members to tilt in all directions if two wires  11  are used and O 1  is located at the tilting center of the engaging members which tilt around the axis perpendicular to the plane containing the two wires  11 . If a shaft type clamping body is used as a raising/lowering means instead of wires; then a variation in extension of the shaft type clamping body is small enough to be ignored. Therefore, the omidirectional tilt center O 1  can be omitted. 
     FIG. 2 shows a concrete example for establishing an omidirectional tilt center. The frame member  21  is accommodated within the frame member  22  with a preset clearance existing therebetween, and the frame member  22  is accommodated within the frame member  23  in the same manner. Two pairs of pinholes  21   a,    23   a  are respectively formed in the opposite side segments of the frame members  21  and  23 . Furthermore, one pair of pinholes  22   a  are formed in two opposite side segments of the frame member  22 , and the other pair of pinholes  22   b  are formed in the other two opposite side segments of the frame member  22 . The pins  24  are inserting through the pinholes  21   a  of the frame member  21  and the pinholes  22   a  of the frame member  22 , and the pins  25  are inserting through the pinholes  22   b  of the frame member  22  and the pinholes  23   a  of the frame member  23 . By this arrangement, the frame members  21 ,  22  and  23  can be fabricated into one integral body (see FIG.  3 ). 
     As shown in FIG. 3, the frame member  21  is capable of swaying around the axes of the pins  24  (namely, X-axis) with respect to the frame member  23 , and the frame member  22  is capable of swaying around the axes of the pins  28  (namely, Y-axis) with respect to the frame member  23 . By this arrangement, the frame member  21  is capable of swaying around X-axis and Y-axis with respect to the frame member  23 . 
     In FIG. 3, the omidirectional tilt center O is located at the intersecting point of X-axis and Y-axis. In order to keep the swaying of the frame members in a smooth way, it is also acceptable to dispose bearings between the pins  24  and the pinholes  21   a,    22   a;  and between the pins  25  and the pinholes  22   b,    23   a.  Furthermore, it is also satisfactory to conduct the swaying of the frame members without engaging the pins with the pinholes. For example, as shown in FIG. 4, two protrusions  26   a,  having acute apexes, are respectively formed on one pair of opposite side segments of a frame member  26 ; and two arms  27   a,  having recesses  27   a  with recessed angles larger than the acute angles of the protrusions  26   a,  extend outward respectively from one pair of opposite side segments of a frame member  27 . By assembling the frame member  26  and the frame member  27 , the swaying movement between the frame members could be made. 
     Two mechanisms, for instance, shown in FIG. 2 are employed to perform the swaying around the omidirectional tilt centers O 1  and O 2  shown in FIG.  1 . Namely, the frame members  23  (or frame members  21 ) are connected to the coupling member  14 , and the remaining frame members  21  (or frame member  23 ) are respectively connected to wires (or rigid members) and the clamping member. Furthermore, in the embodiment shown in FIG. 1, the omidirectional tilt centers O 1  and O 2  can respectively operate solely. However, if a specific geographical relationship between the omidirectional tilt centers O 1  and O 2  is achieved, they can be merged into a single one. Namely, if the omidirectional tilt centers are substantially located at the crystal rotation axis and at the geometric center of the wire connectors  12  of wires, and the omidirectional tilt centers are substantially located at or above the intersecting point of the plane containing the crystal clamping points of the engaging portions and the rotation axis of the crystal; then the two omidirectional tilt centers can be merged into a single one. 
     FIG. 5 is a cross-sectional view of a clamping body according to the first embodiment, which satisfies the above condition. The clamping body  30 , which is substantially the same as that shown in FIG. 2, is consisted of three ring-shaped frame members  31 ,  32  and  33 . The frame member  31  is pivotally supported within the frame member  32  by a pin  34  in a manner capable of tilting without any restraint, and the frame member  32  is pivotally supported within the frame member  33  by a pin  35  in a manner capable of tilting freely. Three wires  36  are engaging on the top surfaces of the frame member  31 , and a clamping portion  38  having a plurality of claws  37  is integrally formed with the frame member  33 . The omidirectional tilt center is located at the intersecting point of the central axis Y of the pin  34  and the central axis X of the pin  35 . The length dispersion between the wires  36  could be absorbed and the tilting of the single crystal could be amended by only one omidirectional tilt center. Moreover, it is also satisfactory to devise the shape and function of the claws  37  the same as those of conventional clamping bodies. 
     FIGS. 6 and 7 show a clamping device according to the second embodiment, which possesses one omidirectional tilt center. The clamping body  40  is composed of a ring-shaped frame member  41  and a clamping portion  42 . Two shank-balls  44  having spherical surfaces are disposed at the ends of the two wires  43 , which suspend the clamping body  40 . The two shank-balls  44  are accommodated within two engaging cavities formed in the frame member  41 . By this arrangement, the frame member  41  is capable of tilting without any restraint around the X-axis passing through the centers of the two shank-balls  44 . Furthermore, one pair of protrusions  42   a,    42   a  extending upward are formed on the outer rim of the upper surface of the clamping portion  42 . The protrusions  42   a,    42   a  are connected with the frame member  41  via two pins  45 ,  45 . By this arrangement, the clamping portion  42  is capable of tilting without any restraint around the Y-axis passing through the axes of the two pins  45 ,  45 . It is also satisfactory to devise the shape and function of the claws  46  the same as those of conventional clamping bodies. 
     The clamping body  40  can be raised or lowered by two wires  43 ,  43 . A variation in extension of the wires  43 ,  43  could be absorbed by tilting of the frame member  41  around Y-axis; therefore tilting of the clamping portion  42  can be avoided. Furthermore, inclination of the single crystal being clamped can be amended by tilting of the clamping portion  42  around X and Y axes toward the intersecting point of the X-axis and Y-axis, namely the rotation axis of the crystal. 
     The above embodiment shows that a rigid member can act as means for correcting the inclination of a single crystal in a retained state even in the case of an ingot manufacturing apparatus of shaft type. 
     The following is a description of the third embodiment with reference to FIGS. 8-13. 
     FIG. 8 is a perspective view showing a clamping device for pulling single crystals according to the third embodiment. FIG. 9 is a side view showing the clamping device shown in FIG. 8, with cross-sectional portions therein. The clamping body  60  comprises a frame member  61  having clamping portions therein; a coupling frame member  62  connecting with one pair of wires  63 ,  63 ; and one pair of coupling wires  64 ,  64  for connecting the frame member  61  and the coupling frame member  62 . The line X 1  (hereinafter referred as axis X 1 ) connecting the engaging points of the wires  63 ,  63  and the coupling frame member  62  is perpendicular to the line Y 1  (hereinafter referred as axis Y 1 ) connecting the engaging points of the coupling wires  64 ,  64  and the coupling frame member  62 . Furthermore, the frame member  61  has a line Y 2  (hereinafter referred as axis Y 2 ) connecting the engaging points of the coupling wires  64 ,  64  and the frame member  61 , and an axis X 2  perpendicular to the axis Y 2 . The detailed description of the axes X 1 , X 2 , Y 1 , and Y 2  will be disclosed below. 
     Plural claws  65  for clamping use are disposed on the inner peripheral wall of the frame member  61  in a manner capable of swaying freely within a preset angular range. A seed chuck  6  is suspended by a crystal pulling wire  4 , which passes through the central openings of the coupling frame member  62  and the frame member  61 . Furthermore, a seed crystal  5  is installed within the lower portion of the seed chuck  6 , and the single crystal  1  is grown with the aid of the seed crystal  5 . In addition, a engagement step  1   a  is formed on the upper portion of the single crystal  1 . The above plural claws  65  are conducted to engage with the engagement step  1   a  so as to clamp the single crystal  1 . Furthermore, in this embodiment, the coupling frame member  62  and the frame member  61  are in the shape of a circular ring. However, the present invention is not limited to the above-described embodiment. 
     FIG. 10 is a top view showing the coupling frame member  62 . FIG. 11 is a cross-sectional view along line A—A of FIG.  10 . As shown in FIG. 11, two engaging holes  63   a,    63   a  having diameters larger than those of the wires  63 ,  63  are formed at the joints of the coupling frame member  62  and the wires  63 ,  63 . The openings of the engaging holes  63   a,    63   a  are extending through the top surface of the coupling frame member  62 , and two through holes  63   b,    63   b  having substantially the same diameters as those of the wires  63 ,  63  are extending through the bottom of the engaging holes  63   a,    63   a.  Furthermore, two engaging holes  64   a,    64   a  having diameters larger than those of the coupling wires  64 ,  64  are formed at the joints of the coupling frame member  62  and the coupling wires  64 ,  64 . The openings of the engaging holes  64   a,    64   a  are extending through the bottom surface of the coupling frame member  62 , and two through holes  64   b,    64   b  having substantially the same diameters as those of the coupling wires  64 ,  64  are formed in the upper portion of the engaging holes  64   a,    64   a.  The lower ends of the wires  63 ,  63  are extending through the engaging holes  63   a,    63   a  and the through holes  63   b,    63   b  and are engaged at the bottom surface of the coupling frame member  62  with two engaging members  66 . Furthermore, the upper portion of the coupling wires  64 ,  64  are extending through the engaging holes  64   a,    64   a  and the through holes  64   b,    64   b  and are engaged at the top surface of the coupling frame member  62  with two engaging members  66 . Due to that the wires  63 ,  63  are capable of bending at bending points P, P, which are located within the engaging holes  63   a,    63   a  and located above the engaging members  66 ,  66  (which are engaging with the lower ends of the wires  63 ,  63 ) by a preset distance; therefore an axis X 1  connecting the bending points P, P is equivalent to a tilting axis. Similarly, the coupling wires  64 ,  64  are capable of bending at bending points Q, Q, which are located within the engaging holes  64   a,    64   a  and above the engaging members  66 ,  66  (which are engaging with the upper ends of the coupling wires  64 ,  64 ) by a preset distance; therefore an axis Y 1  connecting the bending points Q, Q is equivalent to a tilting axis. 
     FIG. 12 is a top view showing the frame member  61 . FIG. 13 is a cross-sectional view along line B—B of FIG.  12 . As shown in FIGS. 12 and 13, two engaging holes  61   a,    61   a  having diameters larger than those of the coupling wires  64 ,  64  are formed at the joints of the frame member  61  and the coupling wires  64 ,  64 . The openings of the engaging holes  61   a,    61   a  are extending through the top surface of the frame member  61 , and two through holes  61   b,    61   b  having substantially the same diameters as those of the coupling wires  64 ,  64  are extending through the bottom of the engaging holes  61   a,    61   a.  The lower ends of the coupling wires  64 ,  64  are extending through the engaging holes  61   a,    61   a  and the through holes  61   b,    61   b  and are engaged at the bottom surface of the frame member  61  with two engaging members  66 . Due to that the coupling wires  64 ,  64  are capable of bending at bending points R, R, which are located within the engaging holes  61 a,  61 a and located above the engaging members  66 ,  66  (which are engaging with the lower ends of the coupling wires  64 ,  64 ) by a preset distance; therefore the axis Y 2  connecting the bending points R, R is equivalent to one tilting axis. 
     According to the structure of this invention, the coupling frame member  62  and the frame member  61  are connected by one pair of coupling wires  64 ,  64 ; therefore the coupling frame member  62  is capable of tilting freely around the axis Y 1  connecting the upper bending points Q, Q of the coupling wires  64 ,  64 . Besides, independent of tilting of the coupling frame member  62 , the frame member  61  is capable of tilting freely around the axis Y 2  connecting the lower bending points R, R of the coupling wires  64 ,  64 . Furthermore, the coupling frame member  62  is capable of tilting freely around the axis X 1 , which is perpendicular to Y 1  axis and connecting the bending points P, P of the wires  63 ,  63 . Moreover, the titling of the coupling frame member  61  around the axis X 2 , which is perpendicular to the above axis Y 2 , is converted into tilting around the axis X 1  through the movement of a parallel-quadric-linkage mechanism, whose joints are located at the upper bending points Q, Q (the coupling frame member  62  side) and the lower bending points R, R (the frame member  61  side) respectively. 
     Therefore, if any elongation dispersion during heavy load or length dispersion between the wires  63 ,  63  occurs, then the coupling frame member  62  tilts around the axis Y 1 . 
     Accordingly, the length dispersion between the wires  63 ,  63  could be absorbed so as to avoid inclination of the single crystal  1 . Moreover, in the event of clamping the single crystal  1  by the claws  65  of the clamping portion of the frame member  61 , if the single crystal  1  is clamped in an inclined attitude, then the frame member  61  will tilt around the axes X 2  and Y 2 . This can avoid inclination of the single crystal  1 . As a result, runout of the single crystal  1  can be reduced to a small amount and the poly-crystallization can be eliminated. Thus, productivity of single crystals could be enhanced. 
     In addition, bending of one pair of wires can equivalently substitute the movement of tilting, thus members used for tilting, such as slide portions and the rotation portions of bearings are not required. By this arrangement, dusts will not be produced and cleanness can be improved during single crystal processes. Moreover, bearing parts is not required, thus the cost can be reduced. The following is a description of the fourth embodiment, with reference made to FIGS. 14-17. 
     In this embodiment, the structures are substantially the same as those of the third embodiment. The method for engaging wires is different to that of the third embodiment. Only the different structure is explained here. Members having the same structure as those of the third embodiment are designated the same numerals. FIG. 14 is a top view showing a coupling frame member according to the fourth embodiment of this invention. FIG. 15 is a cross-sectional view along line c—c of FIG.  14 . Spherical engaging members  67  are respectively installed at the distal ends of the wires  63 ,  63  and the coupling wires  64 ,  64 . As shown in FIGS. 14 and 15, two engaging holes  63   c,    63   c  having diameters larger than that of the spherical engaging member  67  are formed at the joints of the coupling frame member  62  and the wires  63 ,  63 . The openings of the engaging holes  63   c,    63   c  are extending through the bottom surface of the coupling frame member  62 , and two through holes  63   d,    63   d,  having diameters smaller than that of the spherical engaging member  67  and larger than that of the raising/lowering wire  63  by a preset amount, are formed in the upper portions of the engaging holes  63   c,    63   c.  Furthermore, two engaging holes  64   c,    64   c  having diameters larger than that of the spherical engaging member  67  are formed at the joints of the coupling frame member  62  and the coupling wires  64 ,  64 . The openings of the engaging holes  64   c,    64   c  are extending through the top surface of the coupling frame member  62 , and two through holes  64   d,    64   d,  having diameters smaller than that of the spherical engaging member  67  and larger than that of the coupling wire  64  by a preset amount, are formed in the lower portions of the engaging holes  64   c,    64   c.  The lower ends of the wires  63 ,  63  extend through the through holes  63   d,    63   d  and are engaged with the spherical engaging members  67 ,  67  within the engaging holes  63   c,    63   c.  Similarly, The upper ends of the coupling wires  64 ,  64  extend through the through holes  64   d,    64   d  and are engaged with the spherical engaging members  67 ,  67  within the engaging holes  64   c,    64   c.  The axis X 1  connecting the centers P 1 , P 1  of the spherical engaging members  67 ,  67  engaging with the wires  63 ,  63  and the axis Y 1  connecting the centers Q 1 , Q 1  of the spherical engaging members  67 ,  67  engaging with the coupling wires  64 ,  64  are respectively employed as tilting axes. Furthermore, the axis X 1  is perpendicular to the axis Y 1 . 
     FIG. 16 is a top view showing the frame member according to this embodiment. FIG. 17 is a cross-sectional view along line D—D of FIG.  16 . As shown in FIGS. 16 and 17, two engaging holes  61   c,    61   c  having diameters larger than that of the spherical engaging member  67  are formed at the joints of the frame member  61  and the coupling wires  64 ,  64 . The openings of the engaging holes  61   c,    61   c  are extending through the bottom surface of the frame member  61 , and two through holes  61   d,    61   d,  having diameters smaller than that of the spherical engaging member  67  and larger than that of the coupling wire  64  by a preset amount, are formed in the upper portions of the engaging holes  61   c,    61   c.  The lower ends of the coupling wires  64 ,  64  extend through the through holes  61   d,    61   d  are engaged with the spherical engaging members  67 ,  67  within the engaging holes  61   c,    61   c.  Under this circumstance, the axis Y 2  connecting the centers R 1 , R 1  of the spherical engaging members  67 ,  67  within the engaging holes  61   c,    61   c  is employed as the tilting axis. 
     The structure of this embodiment is described as above, same to the previous embodiment, the coupling frame member  62  is capable of tilting freely around the axis Y 1  connecting the centers Q 1 , Q 1  of the spherical engaging members  67 ,  67  engaging with the upper ends of the coupling wires  64 ,  64 . Besides, independent of tilting of the coupling frame member  62 , the frame member  61  is capable of tilting freely around the axis Y 2  connecting the centers R 1 , R 1  of the spherical engaging members  67 ,  67  engaging with the lower ends of the coupling wires  64 ,  64 . Furthermore, the coupling frame member  62  is capable of tilting freely around the axis X 1 , which is perpendicular to Y 1  axis and connecting the centers P 1 , P 1  of the spherical engaging members  67 ,  67  engaging with the wires  63 ,  63 . Moreover, titling of the coupling frame member  61  around the axis X 2 , which is perpendicular to the above axis Y 2 , is converted into tilting around the axis X 1  through the movement of a parallel-quadric-linkage mechanism, whose joints are respectively located at the centers Q 1 , Q 1  of the spherical engaging members  67 ,  67  engaging with the upper ends of the coupling wires  64 ,  64  and the centers R 1 , R 1  of the spherical engaging members  67 ,  67  engaging with the lower ends of the coupling wires  64 ,  64 . 
     Therefore, if any length dispersion between the wires  63 ,  63  occurs, then the coupling frame member  62  tilts around the axis Y 1 . Accordingly, the length dispersion between the wires  63 ,  63  could be absorbed so as to avoid inclination of the clamping portion (the frame member  61 ). Moreover, in the event of clamping the single crystal  1  by the claws  65  of the clamping portion of the frame member  61 , if the single crystal  1  is clamped in an inclined attitude, then the frame member  61  will tilt around the axes X 2  and Y 2 . This can avoid inclination of the single crystal  1 . As a result, runout of the single crystal  1  can be reduced to a small amount and the poly-crystallization can be eliminated. Thus, productivity of single crystals could be enhanced. 
     As described above, the following functions and effects can be obtained by employing this invention. 
     (1) In the event that wires are used as a measure for raising and lowering the clamping body, the clamping portion can be kept in a horizontal attitude even if the wire-engaging surface inclines due to a variation in extension of wires by a heavy load. Therefore, the single crystal can be always clamped in a vertical attitude at its original rotation axis. 
     (2) Even if the single crystal is clamped in an inclined attitude due to shape inaccuracy of the reduced engagement step, the omidirectional tilt center will always guide the gravity center of the single crystal to move back to its original rotation axis. Therefore, runout of the single crystal can be reduced. 
     (3) In the event that a shaft-type raising/lowering means is used, inclination of the wire-engaging surface induced by elongation dispersion is small enough to be ignored. However, it is possible that the single crystal is clamped in an inclined attitude due to shape inaccuracy of the reduced engagement step or manufacturing incorrectness of the clamping body. On this occasion, the omidirectional tilt center will act in the same manner as that described in (2), and the axis of the single crystal will automatically move to its original location. 
     (4) Runout of the single crystal  1  can be reduced to a small amount and the poly-crystallization can be eliminated. Thus, productivity of single crystals could be enhanced. 
     (5) in the event of equivalently substituting tilting with bending of wires, bearing members such as slide portions and rotation portions are not required. Therefore, single crystals can be grown in an uncontaminated and low-priced way. 
     The following is a description of an embodiment of the sacrifice member (for example, a bar-shaped body  120 ) employed in single crystal manufacturing device of this invention, with reference made to drawings. 
     FIGS. 27A,  27 B,  28 A and  28 B are schematic illustrations showing the states of the fifth embodiment according to this invention. The essential portion of an engaging member  150  (equivalent to member  50  in FIG. 18) installed in a single crystal pulling device is enlarged and shown therein. FIGS. 27B and 28B are top views illustrating the states of the fifth embodiment, and FIGS. 27A and 28A are cross-sectional views along lines A—A of FIGS. 27B and 28B. FIGS. 27A and 27B are showing the state before clamping a single crystal. FIGS. 28A and 28B are showing the state of clamping a single crystal. 
     The engaging member  150  is provided with a swaying claw body  102  capable of swaying around the sway axis  112  and a stopper  113 . The swaying claw body  102  can sway, with the restriction of the stopper  113 , back to its initial place by its own weight or a spring urging force. 
     A bar-shaped body  120  is installed on the distal end of the swaying claw body  102  via an engaging member  121 . The bar-shaped body  120  is made of, for example, metal material such as: stainless, nickel or copper. Moreover, the distal end, namely the rear side of the bar-shaped body  120 , is shaped into a circular recess  122 . 
     The curvature of the recess  122  is substantially the same as that of the single crystal to be engaged. 
     When the portion  109  of the single crystal is being engaged, the bar-shaped body  120  installed on the engaging member  150  bends and deforms (see FIG.  28 B). In other words, a deformation margin (space)  122  allowing the deformation of the bar-shaped body  120  is formed behind the bar-shaped body  120 . The bar-shaped body  120  will deform to fill up the deformation margin (space)  122  when a pushing force induced by the weight of the single crystal. Therefore, according to the above single crystal supporting structure, the contact surface between the single crystal and the engaging member  150  is increased and the surface pressure exerted on the single crystal is thus reduced. 
     Namely, in this embodiment, the contact surface between the single crystal and the bar-shaped body  120  can be increased and the surface pressure exerted on the single crystal can be reduced by forming a deformation margin  122  behind the bar-shaped body  120  to allow the deformation of the bar-shaped body  120  and positively deforming the bar-shaped body  120 . Therefore, according to this embodiment, breakage or cracking of the single crystal remaining in a pulled state can be eliminated. 
     On this occasion, the bar-shaped body  120  deforms in a plastic manner; namely its shape can not be restored. Accordingly, the bar-shaped body  120  has to be replaced after each single crystals pulling. 
     FIGS. 29A,  29 B,  29 C and  29 D are schematic illustrations showing a variety of alternative examples for the bar-shaped body  120 . 
     A bar-shaped body  120  in the shape of a hollow pipe is shown in FIG.  29 A. The bar-shaped body  120  is inclined to deform under a stress induced by the weight of a single crystal. A bar-shaped body  120  with metal fibers  123  packed in its hollow interior is shown in FIG.  29 B. By this arrangement, abrupt deformation induced by the weight of a single crystal can be avoided, and sudden load will not be imposed on the single crystal remaining in a pulled state. 
     A bar-shaped body  120  with plural bundled wires  124  packed therein is shown in FIG.  29 C. By this arrangement, abrupt deformation induced by the weight of a single crystal can be avoided. A bar-shaped body  120  consisting of plural bundled wires  124  is shown in FIG.  29 D. Compared with the single thick bar-shaped body shown in FIGS. 27A and 27B, the bar-shaped body shown in FIG. 29D is much easier to deform under a stress. 
     FIG. 30 is an illustration showing the sixth embodiment according to this invention. In this embodiment, plural notches  125  are formed on the rear side (the side opposite to the side in contact with the single crystal) of the bar-shaped body  120 . By this arrangement, the bar-shaped body  120  is easy to bend and deform. FIG. 31 is an illustration showing the seventh embodiment according to this invention. In this embodiment, plural triangular protrusions  126  are formed on the distal end of the swaying claw body  102 . Namely, margin  126 ′ between each pair of the triangular protrusions  126  is used as a recessed space (collapse margin). Therefore, the distal end of the swaying claw body  102  is easy to break down, and the contact surface between the single crystal and the swaying claw body is thus increased. 
     FIGS. 32A,  32 B,  33 A and  33 B are schematic illustrations showing the eighth embodiment according to this invention. FIGS. 32B and 33B are top views illustrating the state of the eighth embodiment, and FIGS. 32A and 33A are cross-sectional views along lines A—A of FIGS. 32B and 33B. FIGS. 32A and 32B are showing the state before clamping a single crystal. FIGS. 33A and 33B are showing the state of clamping a single crystal. 
     In the eighth embodiment, the contact surface between the single crystal and the swaying claw body  102  is increased by improving the shape of the distal end of the claw body  102 . Therefore, the surface pressure exerted on the single crystal can be reduced. In FIGS. 32A,  32 B,  33 A and  33 B, a long thin slot  127  is formed in the distal end of the claw body  102 . The slot  127  extends in a direction substantially perpendicular to the direction in which the weight of the single crystal exerting on the distal end of the claw body  102 . Namely, a space (deformation margin) allowing the portion  128  located between the slot  127  and the single crystal  109  to positively deform during the exerting of a single crystal weight is formed by molding the slot  127  in the distal end of the claw body  102 . Therefore, when the weight of the single crystal is applied, the portion  128  located between the slot  127  and the single crystal  109  deforms and collapses toward the slot  127  by the pushing force coming from the single crystal  109  (see FIGS.  33 A and  33 B). As a result, same as the previous embodiment, the contact surface between the single crystal and the distal end of the swaying claw body in this embodiment is larger than those in conventional ones. Therefore, the surface pressure exerted on the single crystal can be reduced. FIGS. 34A,  34 B,  35 A and  35 B are schematic illustrations showing the ninth embodiment according to this invention. FIGS. 34B and 35B are top views illustrating the state of the ninth and FIGS. 34A and 35A are cross-sectional views along lines A—A of FIGS. 34B and 35B. FIGS. 34A and 34B are showing the state before clamping a single crystal. FIGS. 35A and 35B are showing the state of clamping a single crystal. 
     In the ninth embodiment, same as the previous embodiment, a long thin slot  127  is formed in the distal end of the claw body  102 , and plural notches  129  extending from the slot  127  in a direction perpendicular to the extending direction of the slot  127  are formed. In the above structure, when the weight of the single crystal is applied, the portion  128  located between the slot  127  and the single crystal  109  deforms and collapses toward the slot  127  by the pushing force coming from the single crystal  109  (see FIGS.  35 A and  35 B). During deforming, the notches  129  formed in the portion  128  located between the slot  127  and the single crystal  109  are enlarged (see FIG. 35B) . Compared with those shown in FIGS. 32A,  32 B,  33 A and  33 B, the portion  128  of this embodiment is much easier to bend and deform due to the existence of the notches  129 . Therefore, the contact surface between the single crystal and the swaying claw body in this embodiment can be increased. 
     Furthermore, in the above embodiments, the swaying claw bodies  102  were employed as engaging members for engaging with the single crystal. However, it is also acceptable to use other engaging mechanisms capable of performing the same functions. Moreover, in the above embodiments, one pair of swaying claw bodies  102  were employed to engage with the single crystal. Nevertheless, it is also satisfactory to use more than three swaying claw bodies to engage with the single crystal.