Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
  • H01L21/68—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for positioning, orientation or alignment
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/88—Investigating the presence of flaws or contamination
  • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
  • G01N21/9501—Semiconductor wafers

Definitions

• the invention relates to a device for achieving different tilt angles of planar objects relative to a reference plane and rotation of the object about an axis aligned perpendicular to the surface of the object.
• Devices of this kind can be used to position flat objects and, in particular, for purposes of inspecting substrates, such as semiconductor wafers or flat panels.
• the object is achieved by a device for positioning disk-shaped objects.
• the device comprises a table which can be adjusted in the x-y direction in an adjustment plane, can be rotated about a first axis of rotation aligned perpendicular to the adjustment plane and is intended to receive a platform.
• a fork-shaped frame is mounted on the platform in such a way as to be rotatable about a second axis of rotation, which is aligned perpendicular to its surface and the angle of tilt of which can be set relative to the adjustment plane.
• the fork-shaped frame has a third axis of rotation, which is aligned perpendicular to the second axis of rotation and about which a frame-shaped object holder is mounted in such a way as to be rotatable in the fork-shaped holder for the purpose of turning the object.
• the frame-shaped object holder which carries the object in the edge region of the latter, surrounds a center through which passes a pivoting axis aligned parallel to the adjustment plane and intended for setting the angle of tilt of the second axis of rotation relative to the adjustment plane.
• the table which can be adjusted in the x-y direction in the adjustment plane ensures that object transfer to the frame-shaped object holder can take place in an accurately fitting manner while avoiding any displacement of the object on supporting elements.
• a positive effect is furthermore exerted on productivity since it is possible to eliminate working steps such as prealignment of the object and devices required for this purpose.
• a stable base for rotation of the object is created by means of an arcuate guide in which the platform is mounted for the purpose of setting the angle of tilt relative to the table.
• a mounting, achievable well below the object can thereby be separated in a simple manner from the region of the object supported and thereby protected from particles. Since the pivoting axis of the arcuate guide, said axis being aligned parallel to the adjustment plane, passes through the center of the frame-shaped object holder, the tilting of the platform is associated with tilting of the object in the same way.
• Rotation about the first axis of rotation can also be performed in a very stable manner a long way below the object and allows simple adaptation of the device to the handling direction of a higher-order system.
• the rotary drive for the fork-shaped frame with the aid of which drive rotation of the object about its mid-perpendicular can be achieved, can also be positioned a long way below the object and in an economical manner.
• Said mid- perpendicular can be set to all required angles in space by rotation of the fork- shaped frame, tilting of the platform and hence of the object relative to the adjustment plane and rotation of the table superimposed on these movements.
• the single drive provided for turning the object through 180° can be enclosed with little outlay. Fundamentally, the object can be turned in all positions and even while the object is being rotated.
• the frame-shaped object holder is provided with clamping devices, between which the edge region of the object is clamped when held, the clamping devices comprising rests for the edge region and contact-pressure elements which can be adjusted toward the object to press the edge region of the object against the rests and away from the object to release the clamping devices. It is advantageous if, to allow adjustment of each contact-pressure element, each contact-pressure element is secured on a spring element which is provided on the frame-shaped object holder, is prestressed toward the object to be held and on which a tension element that can be actuated to release the clamping device engages. Particularly suitable as a tension element are clamped-in wires made of a shape memory alloy which shorten in length when heated.
• the rests and the contact-pressure elements have curved surfaces which, in the clamping condition, engage on chamfered edges of the edge region of the object and if each clamping device is provided with a sensor on the frame-shaped object holder to detect the clamped and undamped condition of the object.
• the frame-shaped object holder furthermore comprises an open region for handler access to feed in and remove an object.
• the particular advantages of the frame-shaped object holder are that no troublesome illumination shadows or hindrances to viewing in the area of interest arise at the object in the case of an inspection.
• the object does not make surface contact anywhere but makes only point contact with its oblique edge on the arched rests, which are composed of inert material and do not leave any traces of scratching. Since the clamping devices engage on the object in the regions in which no structuring is provided in the production process, the object can be seen almost completely and from both sides. By means of a sufficiently large number of clamping devices, it is possible to ensure that any notches or flats which may coincidentally be present in the clamping region do not lead to any significant loss of clamping.
• Fig. 1 shows a system of axes of motion used in the positioning device under consideration
• Fig. 2 shows the positioning device with an object which is situated in a horizontal position
• Fig. 3 shows the positioning device in a perspective representation from below
• Fig. 4 shows the positioning device in a rear view, in which the object is tilted
• Fig. 5 shows a basic diagram relating to detection of the position of the object
• Fig. 6 shows the positioning device in a perspective representation from the front and from above, in which the object is tilted
• Fig. 7 shows an encased frame-shaped object holder
• Fig. 8 shows a detail of the opened object holder
• Fig. 9 shows a circuit diagram for the purpose of explaining the operation of the object holder.
• Fig. 1 The diagram in Fig. 1 illustrating the axes of motion is intended to clarify how a disk-shaped object 1, e.g. a semiconductor wafer or a flat panel, can be positioned in space with the device under consideration for the purposes of inspection.
• a disk-shaped object e.g. a semiconductor wafer or a flat panel
• the object 1 which can be turned about a turning axis W for inspection of the front and rear, provision is firstly made for rotation about an axis of rotation ⁇ passing through the center M of the object 1 and corresponding in the inspection position illustrated to the mid-perpendicular to the object 1.
• the turning axis W extends along its diameter.
• the turning axis ⁇ can be tilted at different angles of tilt relative to a vertical z axis of a reference system along a circular arc B by means of a pivoting movement.
• the associated pivoting axis likewise passes through the center M and is aligned parallel to an adjustment plane X-Y, which occupies a horizontal position in the reference system.
• the pivoting axis coincides with the turning axis W.
• a rotary motion about the z axis and translatory X-Y movements in the adjustment plane X-Y can furthermore be superimposed on the adjustments about the turning axis W, the axis of rotation ⁇ and the setting of their tilting relating to the vertical z axis and hence to the adjustment plane X-Y.
• the object 1 in the form of a semiconductor wafer to be positioned is in a position in which both supply and removal of the object 1 can take place.
• this horizontal position in which the object 1 is aligned parallel to the adjustment plane X-Y, the axis of rotation ⁇ and the vertical z axis of the reference system coincide.
• a X-Y- ⁇ table 2 which can be adjusted in the adjustment plane X-Y and rotated about the z axis, carries a platform 3, the angle of tilt of which relative to the adjustment plane X-Y can. be set by a pivoting motion about a pivoting axis S by means of an arcuate guide.
• a fork-shaped frame 8 which is mounted on the platform 3 in such a way as to be rotatable about an axis aligned perpendicular to the surface of the platform 3 and corresponding to the ⁇ axis, acts as a carrier for a frame-shaped object holder 9.
• the frame-shaped object holder 9 surrounds a center M' which coincides, in the case of the object 1 under consideration, with the center M of the latter. At its fork ends, the fork-shaped frame
• the frame-shaped object holder 9 contains bearing and drive elements 10, 11 , by means of which the frame-shaped object holder 9 is mounted rotatably about an axis corresponding to the turning axis W.
• the rotation of the frame-shaped object holder 9 is provided to enable the object 1 to be turned for inspection on both sides.
• the fork-shaped frame 8 is correspondingly wide.
• the pivoting axis S aligned parallel to the adjustment plane
• the pivoting axis S coincides with the diameter of the semiconductor wafer.
• FIG. 3 The view of the positioning device from below in accordance with Fig. 3 shows to a large extent the components of the X-Y- ⁇ table 2 and its drive means.
• a positioning plate 16, which can be displaced in the x and y directions on roller bearings 13, 14, 15 is provided on a base plate 12 fixed to the stand.
• Servomotors
• a table plate 24 is mounted on the positioning plate 16 in such a way as to be rotatable about the z axis by means of bearings (not shown), the power produced by a drive motor 25 being transmitted to the rotatable table plate 24 by means of a toothed-belt drive (likewise not shown). If one of the servomotors 17,
• the leaf springs of the leaf spring couplings each have a stabilizing effect in a perpendicular direction to the respective direction of displacement.
• transport fixings 26 are provided for transportation, by means of which both plates 12, 16 can be connected to one another.
• a drive motor 27 for the fork- shaped frame 8 and a drive motor 28 (see Fig. 2, and not shown in Fig. 4 for the sake of clarity) for the arcuate guide.
• the object 1 is additionally shielded from particles with respect to both motors 27, 28, which, like the associated gear and guide elements, are enclosed, by a bowl-like part 29 (see Fig. 4, and not shown in
• the part 29 furthermore serves as a fixing element for six sensors 30, 31, 32, 33, 34 and 35 for detecting the position of the object 1 as it is fed to the positioning device, in particular as it is transferred to the frame-shaped object holder 9 with the aid of a handling arm (not shown). Corresponding openings in the part 29 allow a clear view of the object 1. Of the sensors, only four, denoted by 30, 31, 34 and 35, can be seen in Fig. 4. The other sensors 32 and 33 can be seen in the basic illustration in Fig. 5, with the aid of which the alignment of the positioning device relative to the object 1 to be fed in will be described in greater detail.
• the servomotors 17 and 18 provided on the X-Y- ⁇ table 2 for the adjustment in the x and y directions are connected to control devices 36, 37, which are connected to outputs of a unit 38 for determining positioning vectors.
• the inputs of the unit 38 are coupled to the sensors
• the deposition points of the object 1 relative to the required feed position are determined with the aid of the sensors 30,
• the unit 38 calculates positioning vectors pointing in the opposite direction to the respective deposition point for the purpose of determining corresponding manipulated variables for the servomotors 17 and 18 in the control devices 36, 37. This results in adjustment of the X-Y- ⁇ table 2 in the adjustment plane X-Y. This process is continued until none of the sensors 30, 31,
• 32, 33, 34 and 35 can detect the presence of the object 1 in its detection range.
• the positioning device has been moved into the feed position relative to the object 1.
• a tilting drive is provided, as shown in Fig. 6, and, in this tilting drive, the drive motor 28 is connected to a spindle drive 39, which adjusts a stud 40 along a linear guide 42 in the direction indicated by 41.
• Seated on the stud 40 is a sleeve 44 which can be displaced vertically in the direction of the arrow 43 and engages on the platform 3 by means of a rotatably mounted driver element 45. If the stud 40 is moved in direction 41 , the platform 3 is pivoted on the arcuate guide. Since the platform 3 assumes different vertical positions during the pivoting motion owing to its connection to the arcuate guide, height compensation is required during power transmission at the linear drive. This is the purpose of the sleeve 44 displaceable on the stud 40 and of the rotatable mounting of the driver element 45.
• Figures 7 and 8 is of annular design and contains an open region 46 for handler access to feed in and remove the object 1.
• Eight clamping devices 47 are distributed along the circular ring in such a way that they lie opposite one another in four pairs. The number of individual holders ensures reliable holding of the object 1, even if one of the clamping devices 47 remains inoperative because of the particular shape of the object 1.
• vertically adjustable rests 48 lying in a common deposition plane are attached to an angled supporting body 49 in such a way that they project into the space enclosed by the circular ring.
• the rests 48 are composed of inert material and have 'an arched surface, with the result that there is only point contact with the edge region of an object 1 resting on them.
• the object holder 9 should hold the objects 1 only in an edge region which is not intended for the formation of structured areas in the production process. It is advantageous if the object 1 rests on one of two mutually opposite chamfers in the edge region. The other chamfer is provided for contact with ball-shaped contact- pressure elements 50, likewise composed of inert material! ceramics or sapphire.
• the contact-pressure elements 50 immobilize the object 1 , with an area below their diameter pressing the object 1 against the point rests 48.
• the necessary contact- pressure force is produced by leaf springs 51 which are secured at one end on first holding pedestals 52 and are preloaded in the direction of the object 1 to be immobilized by the clamping between the rests 48 and the contact-pressure elements 50.
• the contact-pressure elements 50 are secured on the other, freely movable end of the leaf spring 51.
• the counter force required to cancel immobilization is produced with the aid of tension elements which engage on the leaf springs 51 via levers 53 pointing away from the object 1 to be clamped.
• the tension elements are designed as wires 54 composed of a shape memory alloy.
• the wires 54 are present as a double pair, with the result that a defect in a single wire does not lead to failure of a clamping device 47.
• One end of each of the wires 54 is clamped to the lever 53, and the other end is clamped to second holding pedestals 55.
• the holding pedestals 52 and 55 are secured on a printed circuit board 56 and, like the leaf spring 51 and the wires 54, are manufactured from conductive material.
• the angled supporting body 49 is closed off at the top together with the printed circuit board 56 mounted on it by a sectional closure ring 57 which, to partition off the object 1 from the printed circuit board 56, has openings only for the rests 48 and the contact- pressure elements 50.
• the tensile force is made to act in the wires 54 by heating resulting from a supply of electric current, whereupon the wires 54 shorten, with the result that the leaf springs 51 are pulled back away from the object 1 together with the contact- pressure elements 50. This actuation does not require any supports and is therefore completely free from the production of particles in the vicinity of the object 1.
• Fig. 9 illustrates, in a diagram, the action of the eight clamping devices 47.
• Circuit components 58 connected in series represent the clamping devices 47, each of the four resistors 59 which it contains corresponding to one of the wires 54.
• the overall unit made up of the circuit components 58 is fed with a constant current by a power source 60.
• a voltage meter 61 is used to measure a total increased voltage drop, which occurs in the event of a malfunction. This can occur if a defect occurs in one of the wires 54.
• sensors 63 in conjunction with angled leaf spring end pieces 64 on the freely movable ends of the leaf springs 51 are used to distinguish between the states of clamping and release of the object 1 , in which the clamping devices 47 may be. Owing to the different deflections of the leaf spring end pieces 64 in the two states, the sensors 63 are unactuated in the state of clamping while, in the state of release, the leaf spring end pieces 64 project into the detection zones of the sensors 63 to form a signal.
• the ball-shaped contact-pressure elements 50 are additionally provided with a securing element, in the present example in the form of a cylindrical pin 65 which projects from the contact-pressure element 50 in the direction of the object 1 and, in normal operation does not touch the object 1.
• the cylindrical pin 65 prevents the object 1 from pushing the leaf spring 51 out beyond the ball wedge formed to such an extent that the object can fall out when there is a non-nominal impact effect during inspection of the rear side.
• the leaf springs 51 are dimensioned in such a way that normal upside down operation is no problem.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Biochemistry (AREA)
• Manufacturing & Machinery (AREA)
• Chemical & Material Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Health & Medical Sciences (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• Analytical Chemistry (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)
• Length Measuring Devices With Unspecified Measuring Means (AREA)
• Details Of Measuring And Other Instruments (AREA)
• Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)

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• 2000
  • 2000-06-09 DE DE2000128569 patent/DE10028569A1/de not_active Withdrawn
• 2001
  • 2001-05-10 JP JP2002510916A patent/JP2004503769A/ja active Pending
  • 2001-05-10 AU AU2001263048A patent/AU2001263048A1/en not_active Abandoned
  • 2001-05-10 EP EP01937297A patent/EP1311826A1/en not_active Withdrawn
  • 2001-05-10 WO PCT/US2001/015193 patent/WO2001096836A1/en active Application Filing

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