Positioning device

Abstract

The invention relates to a positioning device for positioning a substrate, in particular a wafer, comprising: a process chamber; a base body; a carrier element which comprises a support for supporting the substrate, the carrier element being arranged above the base body and formed movable in terms of distance from the base body; and a holder for an additional substrate, in particular an additional wafer or a mask, the holder being arranged opposite the carrier element; wherein there is, between the base body and the carrier element, a sealed-off cavity to which a pressure, in particular a negative pressure, can be applied so as to prevent undesired movement of the carrier element as a result of the action of an external force.

Claims

1. A positioning device for positioning a substrate, comprising: a process chamber; a base body; a carrier element which comprises a support for supporting the substrate, the carrier element being arranged above the base body and formed movable in terms of distance from the base body; and a holder for an additional substrate, the holder being arranged opposite the carrier element; wherein there is, between the base body and the carrier element, a sealed-off cavity to which a pressure can be applied so as to prevent undesired movement of the carrier element as a result of the action of an external force, wherein the process chamber is arranged at least in part between the holder and the carrier element, wherein an adjustment element is arranged between the base body and the carrier element so as to adjust the distance of the carrier element from the base body, wherein the adjustment element comprises a number of extensible and retractable pins, so as to vary the distance of the carrier element from the base body.

2. The positioning device of claim 1, wherein the sealed-off cavity comprises a pressure terminal, via which the pressure in the cavity can be controlled.

3. The positioning device of claim 1, wherein the positioning device comprises a restoring element, which acts between the base body and the carrier element.

4. The positioning device of claim 1, wherein a number of support elements, which set a minimum distance of the carrier element from the base body, are arranged between the base body and the carrier element.

5. The positioning device of claim 1, wherein the positioning device comprises a guide for guiding the movement of the carrier element.

6. The positioning device of claim 1, wherein the carrier element comprises a fixing device, by means of which the substrate positioned on the support can be fixed.

7. The positioning device of claim 1, wherein there is, between the carrier element and the holder, a process cavity, the size of which is set at least in part by the distance between the carrier element and the holder.

8. The positioning device of claim 7, wherein the process cavity is part of the process chamber or defines the process chamber.

9. The positioning device of claim 7, wherein the positioning device comprises sealing means for sealing off the process cavity.

10. The positioning device of claim 7, wherein an overpressure or a negative pressure can be applied to the process cavity and/or it can be evacuated, or wherein the process cavity is provided with a gas terminal through which a gas can be introduced.

11. The positioning device of claim 1, wherein the positioning device comprises at least one spacer, which is insertable between the base body and the holder so as to adjust and/or fix a distance between the base body and the holder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further embodiments are explained in greater detail with reference to the accompanying drawings, in which:

(2) FIG. 1 is a schematic drawing of part of a positioning device for a substrate;

(3) FIG. 2 is a schematic drawing of a positioning device in accordance with a further embodiment;

(4) FIG. 3 is a flow chart of a method for bringing a substrate together with a further substrate; and

(5) FIG. 4a-g are schematic drawings of the positioning device of FIG. 2, which is being used for connecting two substrates.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 is a schematic drawing of part of the positioning device 100 for positioning a substrate 101 in accordance with an embodiment.

(7) The positioning device 100 comprises a base body 105 and a carrier element 107, which comprises a support 109 for supporting the substrate 101, the carrier element 107 being arranged above the base body 105 and being formed movable in terms of distance from the base body 105.

(8) The positioning device 100 further comprises a holder 111 for a further substrate 103, the holder 111 being arranged opposite the carrier element 107.

(9) In the positioning device 100, there is, between the base body 105 and the carrier element 107, a sealed-off cavity 113 to which a pressure, in particular a negative pressure, can be applied so as to prevent undesired movement of the carrier element 107 or the support substrate 101 towards the holder as a result of the action of an external force.

(10) By means of the positioning device 100, the distance of the substrate 101 from the further substrate 103 fixed to the holder 111 can further be adjusted. For example, the positioning device 100 may bring together and/or bring into contact the substrate 101 and the further substrate 103. Subsequently, a lithography process, a bonding process and/or an imprint process may be carried out.

(11) The substrate 101 and/or the further substrate 103 may each be a wafer. The further substrate 103 may further be a mask, in particular a photolithography mask, or a stamp, in particular a microimprint or nanoimprint stamp for the substrate 101.

(12) The substrate 101 and/or the further substrate 103 may be substantially the same size, in particular have a substantially equal periphery. The further substrate 103 may be formed as a lid and/or cover for the substrate 101. The further substrate 103 may be formed transparent to light.

(13) The substrate 101 and/or the further substrate 103 may each be disc-shaped. The substrate 101 and/or the further substrate 103 may each have a substantially round periphery having a diameter of 2, 3, 4, 5, 6, 8, 12 or 18 inches. The substrates 101, 103 may further be substantially planar, and may each have a thickness of between 50 and 3000 μm. The substrates 101, 103 may each have a straight edge (flat) and/or at least one groove (notch). The substrates 101, 103 may further be polygonal, in particular square or rectangular, in form

(14) The substrate 101 and/or the further substrate 103 may each be formed from a semiconductor material, for example silicon (Si) or gallium arsenide (GaAs), a glass, for example quartz glass, a plastics material or a ceramic. The substrate 101 and/or the further substrate 103 may each be formed from a monocrystalline, polycrystalline or amorphous material. Further, the substrates 101, 103 may each comprise a plurality of composited materials. At least one of the substrates 101, 103 may be coated with a coating, for example a polymer such as a photoresist or an adhesive, on at least one face. Further, at least one of the substrates 101, 103 may comprise a metal coating, for example a structured chromium layer.

(15) The substrate 101 and/or the further substrate 103 may each comprise structures, in particular regularly arranged structures, on at least one substrate surface. The structures may form elevations and/or cavities on the substrate surface. The structures may comprise electrical circuits, for example transistors, LEDs or photodetectors, electrical conducting tracks which connect these circuits, or optical components. The structures may further comprise MEMS or MOEMS structures. The substrate 101 and/or the further substrate 103 may further comprise residues or impurities, for example glue beads, on one or both substrate surfaces. The structures or residues may be on a surface of the substrate 101 or of the further substrate 103 facing the other substrate in each case.

(16) The base body 105 and/or the carrier element 107 may each be formed of plastics material or metal, in particular aluminium. The carrier element 107 may be coupled to the base body 105. For example, the base body 105 comprises a recess into which the carrier element 107 may be inserted at least in part. The cavity 113 may be formed by the part of the recess in the base body 105 which is not received by the carrier element 107.

(17) The movement of the carrier element 107 in terms of distance from the base body 105 is substantially perpendicular to the base body. Additionally, a component oblique thereto may also be used. As a result of the movement of the carrier element 107 with respect to the base body 105, the distance of the carrier element 107 from the base body 105 is varied; in particular, a height of the carrier element 107 above the base body 105 may be varied.

(18) The carrier element 107 and/or the base body 105 may form a chuck.

(19) The support 109 may comprise a recess in the carrier element 107 or be formed as a recess in the carrier element 107. The periphery of the recess may substantially correspond to the periphery of the substrate 101, in such a way that the substrate 101 can be inserted into the recess.

(20) The carrier element 107 may comprise a fixing device (not shown in FIG. 1), for fixing the supported substrate 101. This fixing is for example mechanical, pneumatic and/or electrostatic. For example, this fixing prevents the substrate from being released from the support by the external force. The support 109 and/or the carrier element 107 may comprise fixing means such as brackets and/or suction openings for this purpose. The fixing device may be a clamping device.

(21) The holder 111 is formed to orientate a surface of the further substrate 103 towards the substrate 101 positioned on the carrier element 107. The substrate 103 is fixed in the holder 111 mechanically, pneumatically or electrostatically. The holder 111 is for example a vacuum holder, which presses in or sucks in and fixes the further substrate 103 by means of a negative pressure.

(22) The position of the holder 111 may further be adjustable in a plane parallel to the carrier element 107 and the supported substrate 101 and/or perpendicular to the carrier element 107 and the supported substrate 101. For example, the holder 111 makes possible precise positional adjustment of the further substrate 103 parallel to the surface of the substrate 101 supported on the carrier element 107, so as to make orientation (alignment) of the substrates 101, 103 possible. For the same purpose, the carrier element 107 and/or the base body 105 may also be movable transverse to the supported substrate 101.

(23) The holder 111 may be formed transparent to light, in particular in an ultraviolet wavelength range. In particular, the holder 111 may be formed from glass or a transparent plastics material. This makes it possible to shine light through the holder 111, for example so as to illuminate the substrate 101 through a mask fixed to the holder 111, or so as to cure a bonding adhesive between the substrates 101, 103.

(24) It may be possible to apply a further pressure, in particular an overpressure, to the sealed-off cavity 113 so as to move the carrier element 107 towards the holder 111 in a targeted manner. In this way, the distance between the substrates 101, 103 can be reduced, or the substrates 101, 103 can be brought into contact in a targeted manner.

(25) To regulate the pressure, the sealed-off cavity 113 may comprise a pressure valve (not shown in FIG. 1).

(26) The example positioning device 100 in FIG. 1 further comprises an adjustment element 115, a guide 117 and a restoring element 119.

(27) The adjustment element 115 is formed for precisely adjusting the distance of the carrier element 107 from the holder 111. The adjustment element 115 may be arranged between the base body 105 and the carrier element 107. The adjustment element 115 may further assist in pneumatic adjustment of the distance of the carrier element from the holder by applying pressure to the cavity 113.

(28) The adjustment element 115 may comprise a lifting element, in particular a pneumatic lifting element. The adjustment or lifting element 115 may comprise a number of pins which are received at least in part in the base body. The pins may be extensible and retractable, so as to vary the distance of the carrier element 107 from the base body 105. The lifting elements may comprise a piezo element or a plurality of piezo elements.

(29) The adjustment element 115 may be actuable by way of control commands to adjust the distance of the carrier element 107 from the base body 105.

(30) The guide 117 is formed to guide the movement of the carrier element 107 so as to prevent undesired lateral displacements of the carrier element 107.

(31) The restoring element 119 is in this case a spring which is arranged between the base body 105 and the carrier element 107. The restoring element 119 can additionally promote the pneumatic fixing of the carrier element 107.

(32) In a further embodiment, the adjustment element 115 is formed by the cavity between the base body 105 and the carrier element 107 to which pressure is applied. Thus, by applying a pressure to the cavity 113, it is possible both to adjust the distance of the carrier element 107 from the base body 105 and to fix the position of the carrier element 107.

(33) FIG. 2 is a schematic drawing of the positioning device 100 in accordance with a further embodiment, which generally corresponds to the first embodiment.

(34) FIG. 2 shows the positioning device 100 with a process chamber, in particular for a lithography process or a bonding process, with a process cavity 201. The process cavity 201 is positioned between the carrier element 107 and the holder 111. The size of the process cavity 201 is substantially set by the distance between the carrier element 107 and the holder 111.

(35) The process cavity 201 may form part of the process chambers, or the process cavity 201 can be the process chamber, in particular for a lithography or bonding process. An overpressure or negative pressure may be applied to the process cavity 201 and/or it may be evacuated. Further, the process cavity 201 may be filled with a gas, in particular helium. This makes it possible to process the substrates 101, 103 in a controlled process environment.

(36) In an embodiment, evacuating the process cavity 201 makes it possible to establish vacuum contact between the substrate 101 and the further substrate 103. For this purpose, the process cavity 201 is initially evacuated. Subsequently, the positioning device 100 moves the substrate 101 towards the further substrate 103, so as to bring the two substrates 101, 103 into contact. Structures such as cavities on the surface of the substrate 101 and/or of the further substrate 103 can thus be efficiently evacuated before the substrates 101, 103 are contacted.

(37) The application of pressure to the process cavity 201 between the carrier element 107 and the holder 111 can bring about or amplify the action of an external force on the carrier element. For example, when the process cavity 201 is evacuated this results in a negative pressure which brings about the action of an external force on the carrier element 107 and/or the supported substrate 101. This external force can cause the carrier element 107 or the substrate 101 to lift and the substrates 101, 103 to be pressed together before all structures on the respective substrate surfaces have been fully evacuated. Because a pressure is now also applied to the cavity 113 between the carrier element 107 and the base body 105, this force can be compensated and the substrates 101, 103 can be prevented from pressing together prematurely.

(38) The action of an external force on the carrier element 107 or the substrate 101 may be the result of a pressure difference between the cavity 113 and the process cavity 201. By applying a suitable pressure to the cavity 113, this pressure difference and the resulting force can be minimised. After the process cavity 201 between the substrates is fully evacuated, the adjustment element 115 can move the carrier element 107 towards the holder 111 so as to bring the two substrates 101, 103 together. Vacuum contact can thus be established between the substrates 101, 103. Alternatively, an overpressure may be applied to the cavity 113 so as to move the carrier element 107 towards the holder 111 and bring the two substrates 101, 103 into contact.

(39) FIG. 2 further shows an example of fixing the substrate 101 to the support 109 and the further substrate 103 to the holder 111 by means of vacuum suction. For this purpose, the support 109 and the holder 111 each comprise a plurality of suction openings which fix the substrate 101 or the further substrate 103 by means of a negative pressure.

(40) In FIG. 2, the adjustment element 115 comprises a plurality of support elements 205a-c, so as to set a minimum distance of the carrier element 107 from the base body 105 and from the further substrate 103 in the holder 111. If there is a strong negative pressure in the cavity 113, the carrier element 107 can thus be prevented from pressing directly onto the base body 107.

(41) In the example drawing of FIG. 2, the substrate 101 comprises structuring on the upper and the lower face. The structuring comprises regular structures, which are formed for example by cavities and/or electrical circuits. For example, the structures on the surface of the substrate 101 are LEDs and/or detectors which are embedded in respective cavities. The structuring of the substrate surface in FIG. 2 further comprises impurities in the form of glue beads 211 on the surface facing the further substrate 103. When the substrates 101, 103 are brought together, the further substrate 103 can be pressed onto the glue bead 211, resulting in an adhesive layer between the substrates 101, 103. The further substrate 103 may comprise transparent lids or covers for individual structures on the substrate 101, which are held in position above the structures after the adhesive layer cures.

(42) The example positioning device 100 in FIG. 2 further comprises a wedge-shaped spacer 203 and sealing means 207, 209.

(43) The spacer 203 is inserted between the base body 105 and the holder 111 so as to prevent undesired movement of the holder towards the base body.

(44) When the process cavity 201 is evacuated, the negative pressure between the holder 111 and the carrier element 107 may bring about a further external force on the holder. This further external force may also cause the holder and the carrier element 107 or the supported substrate 101 to be pressed together. To prevent this, the spacer 203 is inserted between the holder and the base body before the process chamber 201 is evacuated.

(45) The sealing means 207 is formed to seal off the cavity 113, in particular at different distances of the carrier element 107 from the base body 105. The sealing means 207 is preferably configured as a sealing ring and/or sealing lip, in particular an inflatable sealing lip.

(46) The further sealing means 209 seals the process cavity 201 or the process chamber 201 at different distances of the holder 111 from the carrier element 107. For this purpose, the further sealing means 209 may also comprise a sealing ring and/or an inflatable sealing lip. The sealing lip of the sealing ring may be pressed against the holder 111 to seal off the process cavity 201.

(47) FIG. 3 is a flow chart of a method 300 for bringing the substrate 101 together with the further substrate 103 in accordance with an embodiment. The substrates 101, 103 may each be a glass or semiconductor substrate. Further, the substrate 101 may be a wafer, and the further substrate 103 may be a mask or a stamp. The substrates 101, 103 may correspond to the substrates 101, 103 shown in FIG. 1 and/or FIG. 2.

(48) The method 300 may be carried out using the positioning device of FIG. 1 and/or FIG. 2, and comprises fixing 301 the substrate 101 opposite the further substrate 103, evacuating 303 the sealed-off cavity 113 below the substrate 101 so as to prevent undesired movement of the substrate due to the action of an external force, and moving 305 the substrate 101 towards the further substrate 103 in a controlled manner.

(49) The method 300 in FIG. 3 further comprises connecting 307, in particular bonding, the substrates 101, 103 which are brought together.

(50) If the method 300 is carried out using a positioning device 100 which, as shown by way of example in FIG. 2, comprises a process chamber 201, this process chamber 201 can be evacuated before the carrier element 107 is moved towards the further substrate 103 in a controlled manner 305. Before, during or after this evacuation, a negative pressure may be applied to the cavity 113 between the carrier element 107 and the base body 105, so as to prevent premature movement of the carrier element 107 towards the further substrate 103 and ensure full evacuation of structures and cavities on the substrate surfaces.

(51) FIG. 4a-g are schematic drawings of the positioning device 100 of FIG. 2 during a connection process for connecting the two substrates 101, 103 in accordance with an embodiment.

(52) FIG. 4a shows the initial state of the connection process. The substrate 101 comprising the glue beads is positioned on the support 109 of the carrier element 107, and the further substrate 103 is fixed to the holder 111. The support 109 and the holder 111 fix the substrates 101, 103 by means of a negative pressure. The pressure difference by means of which the substrate 101 is sucked onto the support 109 is for example P.sub.Wafer=−0.95 bar. A negative pressure is also applied to the cavity 113 between the carrier element 107 and the base body 105, resulting in a pressure difference of P.sub.Chuck=−0.95 bar from the ambient pressure. The inflatable sealing lip 209 is retracted in FIG. 4a. Thus, the pressure in the process chamber 201 corresponds to the ambient pressure (pressure difference P.sub.Chamber=0 bar).

(53) FIG. 4b shows a subsequent extension of the inflatable sealing lip 209 to seal off the process chamber 201. Further, the holder 111 is lowered and fixed at a set distance from the base body 105 by means of the wedge 203.

(54) FIG. 4c shows an evacuation of the sealed-off process chamber 201. This results in for example a negative pressure difference from the ambient pressure of P.sub.Chamber=−0.75 bar. Since a negative pressure is also applied to the pressure chamber 113, the evacuation of the process chamber 201 does not initially result in a movement of the carrier element 107 towards the holder 111.

(55) In the following process step, shown in FIG. 4d, an overpressure of for example P.sub.Chuck=+0.5 bar is applied to the cavity 113. As a result, the wafer support movable in the z-direction presses the substrate 101 located on the carrier element 107 against the upper substrate 103. The glue beads can thus be compressed between the substrates 101, 103 and form a uniform adhesive layer. For a laterally adjustable carrier element 107 or a laterally adjustable support 109, adjustment is also possible at this time.

(56) FIG. 4e shows subsequent retraction of the sealing lip 209 and removal of the wedge 203.

(57) If fine adjustment was not possible in the previous step, the carrier element 107 can now be moved further towards the holder, sucked onto the chuck support and adjusted. This lowering of the carrier element is shown in FIG. 4f.

(58) FIG. 4g shows subsequent illumination of the connected substrates with UV light 401 to cure the adhesive layer between the substrates 101, 103.

(59) The positioning devices 100 shown in FIG. 1, 2 and FIG. 4a-g can be integrated into manufacturing systems for microstructure components, for example lithography systems such as mask aligners, laser writers, bonding systems such as wafer bonders, steppers, etching systems or cleaning systems.

(60) The production systems may be formed for manufacturing process in which a vacuum is to be produced between substrates 101, 103 and/or vacuum contact is to be established between substrates 101, 103, for example for vacuum bonding.

LIST OF REFERENCE NUMERALS

(61) 100 Positioning device

(62) 101 Substrate

(63) 103 Further substrate

(64) 105 Base body

(65) 107 Carrier element

(66) 109 Support

(67) 111 Holder

(68) 113 Cavity

(69) 115 Adjustment element

(70) 117 Guide

(71) 119 Restoring element

(72) 201 Process cavity

(73) 203 Wedge

(74) 205a-c Support elements

(75) 207 Sealing means

(76) 209 Further sealing means

(77) 211 Adhesive bead

(78) 300 Method for bringing a substrate together with a further substrate

(79) 301 Fixing

(80) 303 Evacuating

(81) 305 Moving

(82) 307 Connecting

(83) 401 UV light