WO2024051888A1 - Wafer holder for electrically contacting brittle semiconductor wafers and use - Google Patents

Wafer holder for electrically contacting brittle semiconductor wafers and use Download PDF

Info

Publication number
WO2024051888A1
WO2024051888A1 PCT/DE2023/100639 DE2023100639W WO2024051888A1 WO 2024051888 A1 WO2024051888 A1 WO 2024051888A1 DE 2023100639 W DE2023100639 W DE 2023100639W WO 2024051888 A1 WO2024051888 A1 WO 2024051888A1
Authority
WO
WIPO (PCT)
Prior art keywords
mat
flat side
metal
wafer holder
wafer
Prior art date
Application number
PCT/DE2023/100639
Other languages
German (de)
French (fr)
Inventor
Jörg BAHR
Jürgen CARSTENSEN
Rainer Adelung
Original Assignee
Christian-Albrechts-Universität Zu Kiel
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Christian-Albrechts-Universität Zu Kiel filed Critical Christian-Albrechts-Universität Zu Kiel
Publication of WO2024051888A1 publication Critical patent/WO2024051888A1/en

Links

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
    • H01L21/683—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 supporting or gripping
    • H01L21/687—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 supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—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 supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
    • H01L21/68735—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 supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by edge profile or support profile
    • 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
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67017—Apparatus for fluid treatment
    • H01L21/67063—Apparatus for fluid treatment for etching
    • H01L21/67075—Apparatus for fluid treatment for etching for wet etching
    • H01L21/67086—Apparatus for fluid treatment for etching for wet etching with the semiconductor substrates being dipped in baths or vessels
    • 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
    • H01L21/683—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 supporting or gripping
    • H01L21/6838—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 supporting or gripping with gripping and holding devices using a vacuum; Bernoulli devices
    • 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
    • H01L21/683—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 supporting or gripping
    • H01L21/687—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 supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—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 supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
    • H01L21/68785—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 supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by the mechanical construction of the susceptor, stage or support

Definitions

  • the invention relates to a wafer holder for large-area electrical and/or thermal contacting of a wafer using negative pressure, particularly applicable in the electrochemical or wet chemical processing of semiconductor wafers.
  • contacting is to be understood as the generation of a non-persistent non-positive contact between a flat side of a wafer and a metallic electrode, whereby the metallic electrode is to be understood as a good electrical conductor and/or as a heat conductor.
  • the contacting should be over a large area in the sense that the electrode contacts the majority of the wafer flat side, typically even almost the entire wafer flat side.
  • a device that is well suited for contacting, for example, silicon (Si) wafers is already presented in the publication DE 102013 104469 B4. It is based on the concept of a frame with a movably mounted metal block arranged inside the frame as an electrode.
  • the frame has a circumferential groove with an O-ring arranged in the groove.
  • the metal block for its part, forms a gas-tight seal with the frame in every position within its range of movement. If a wafer is placed on the O-ring in the frame, the space between the wafer and the metal block can be subjected to negative pressure.
  • the metal block is pulled towards the wafer - possibly with a metal foil resting on the metal block - and brought into large-area contact with very little deflection of the wafer.
  • the metal block can be subjected to large currents - several 100 A to kA - which is particularly necessary in etching processes.
  • ridges could be formed as an integral part of the disk if coplanarity can be maintained. It should be noted that the ridges need not necessarily be concentric or circular as long as that they are continuous or closed-looped and that each continuous ridge has a progressively larger perimeter as they extend towards the outer periphery of the disk surface.”
  • the invention sets itself the task of realizing large-area electrical and/or thermal contacting of a flat side of a wafer using negative pressure, even for very brittle semiconductor wafers, without the risk of breakage, by proposing a new design of a wafer holder.
  • a wafer holder for large-area electrical contacting of a semiconductor wafer comprising a metal body with a metal flat side offset on the top by the offset height L and a gas coupling arranged on the bottom and at least one gas channel open in the metal flat side and leading to the gas coupling, the metal body being designed to be subjected to electrical currents of the order of magnitude kA and a flexible mat resting on the metal body formed from an inert polymer, the mat having a recess for the passage of the metal flat side and surrounding the edge of the metal flat side is arranged fixed parallel to the metal flat side, the mat on the side facing away from the metal body along a plurality of closed, mathematically similar, concentric contours each having one of at least three mat thicknesses M, R, G and the mat thicknesses with the property M > R > L > G are predetermined in such a way that a first contour of the mat thickness M is designed for contacting the edge region of a wafer and on a second smaller contour of the mat
  • the subclaims are directed to advantageous embodiments of the wafer holder.
  • the inert polymer can in particular be a fluoropolymer or a silicone.
  • the mat thickness M can be a few millimeters (a few millimeters can be about 1-4 millimeters), particularly preferably 2-3 millimeters.
  • the mat thickness M can preferably be between 200 and 300 micrometers greater than the settling height L of the metal flat side.
  • the mat thickness G can in particular correspond to half the mat thickness M.
  • the first and second contours can each have a width of at least 1 millimeter.
  • the metal foil can be made of gold or aluminum.
  • the thickness of the metal foil can be in particular 30-100 micrometers.
  • the mat thickness R can be between 50 and 150 micrometers greater than the settling height L of the metal flat side.
  • the wafer holder for large-area electrical contacting of brittle semiconductor wafers, in particular indium phosphide wafers.
  • the O-ring in the context of the device according to the document DE 10 2013 104 469 B4 is replaced by one that is integrated into a flexible mat made of an inert polymer and runs along a closed contour Back structure and (ii) the metal flat side for contacting is completely immovable.
  • the wafer resting on the back structure approaches the metal flat side - the metal block - when the negative pressure is built up through the gas channel by lowering the wafer onto the metal flat side while the flexible back structure gives way. So only the small mass of the wafer itself and the even smaller mass of one or more back structures in the flexible mat are moved. The force load and deflection of the wafer is minimized by the elastic deformation of the inert polymer.
  • the inert polymer comes into contact with - through energization - hot metal and, at least outside the outermost back structure, also with an electrolyte. It must therefore be chemically and thermally stable. Fluoropolymers such as Teflon® or silicones are preferred as inert polymers.
  • a mat made of inert polymer can now be processed quite precisely using laser ablation and structured along predetermined contours. Structuring in the context of this description includes the laser ablation of polymer material to locally reduce the mat thickness from an initial value, e.g. M, to smaller values, e.g. R and G.
  • This description understands a closed contour to be a two-dimensional, self-recurring line in the mat plane with a predetermined line width, the contour width.
  • a plurality of contours are provided on the top of the flexible mat. These contours should be arranged concentrically and be similar in a mathematical sense, i.e. they should be able to be brought to congruence by rotation and/or stretching.
  • the individual contours are assigned different mat thicknesses M, R, G, which are set up, for example, by laser ablation along the contours. For this reason, the contours cannot overlap, and in particular all the contours have different diameters.
  • Two contours are said to be immediately adjacent if they run completely parallel to each other without any space in the mat plane. Each contour can have a maximum of two immediately adjacent contours, namely a smaller inner one that runs closer to the common center everywhere and a larger outer one that runs further away from the center everywhere.
  • the invention introduces two contours of the mat thickness G ⁇ R ⁇ M which are immediately adjacent to the supporting structures - to be deformed (contours with mat thicknesses M, R), which can also be referred to as trench structures. Their purpose is to mechanically decouple the supporting structures from the lateral neighborhood in the mat so that force components parallel to the mat cannot affect this neighborhood. With the help of these trenches on both sides of the supporting back structures, there is a significantly improved gas tightness between the wafer and the metal block; the negative pressure applied is stable and consistent.
  • Fig. 1 is a sketch of a sectional view perpendicular to the flat metal side and the wafer lying on it to show the mat thicknesses according to the invention.
  • the cut runs perpendicular to the offset metal flat side 12 of the metal block 10.
  • the metal flat side 12 protrudes from the rest of the top side of the metal block 10 by the offset height L and is arranged in its center. It also has at least one opening for a gas channel 14, which passes through the interior of the metal block 10 and leads into a gas coupling 16 on the underside of the metal block 10.
  • the gas coupling 16 can be designed as a lockable tap. It is used to connect a device for sucking in gas from the metal flat side 12, i.e. to apply negative pressure.
  • the metal block 10 carries all other components of the wafer holder, in particular the flexible mat 20 made of inert polymer. It should be noted here that the parts of the metal block 10 on which the mat 20 rests could also be replaced by another material, for example by an electrically insulating material, such as a plastic. In this case, the settling height L of the metal flat side 12 would be understood to mean the difference in height between the metal flat side 12 and the support surface of the mat 20, which can also be easily seen from FIG. 1.
  • the mat 20 has an initial mat thickness M > L and a recess for the passage of the metal flat side 12, i.e. a central area of the mat 20 is cut out, and the mat 20 lies on the top of the metal block 10 in such a way that it covers the edge of the metal flat side 12 surrounds.
  • the mat 20 is thus oriented parallel to the metal flat side 12 and is fixed in position by suitable fixing elements such as screws or clamps on the edge of the mat 20 (not shown).
  • the mat 20 usually does not protrude beyond the edge of the metal block 10.
  • the initial mat thickness of the flexible mat 20 can preferably be 2 to 3 millimeters. It can then be reduced to a predetermined mat thickness M everywhere - that is, over the entire surface - but it is clearly expedient to equate the mat thickness M with the initial mat thickness.
  • a first closed contour 22 with mat thickness M is provided for the gas-tight contacting of the wafer 40.
  • a second contour 24 with a mat thickness R that is smaller in diameter and therefore further inward serves to support the edge of a thin metal foil 30, which otherwise rests on the metal flat side 12 and extends beyond the edge of the metal flat side 12, but not to the first contour 22 is enough.
  • the first contour 22 preferably has a contour width of approximately 1 millimeter, while the second contour 24 can also be designed to be wider than 1 millimeter in order to establish the largest possible contact area between the metal foil 30 and the edge of the wafer 40.
  • the usual “sagging” of the metal foil 30 within the supporting contour 24, which leads to the metal foil 30 resting on the metal flat side 12 is not shown in FIG. 1 to simplify the sketch.
  • the mat thickness M is preferably between 200 and 300 micrometers greater than the settling height L of the metal flat side 12.
  • the first contour 22 projects beyond the fixedly positioned metal flat side 12 by 200-300 micrometers in the unloaded state.
  • the edge of the metal film 30 should be slightly higher on the second contour 24 than on the flat metal side 12;
  • the mat thickness R of the second contour is preferably set to be between 50 and 150 micrometers greater than the settling height L of the metal flat side 12.
  • the metal foil 30 preferably consists of a good electrical conductor material, preferably one of the element metals gold or aluminum.
  • the metal foil 30 is preferably between 30 and 100 micrometers thick.
  • the purpose of the metal foil 30 is to supply current to the edge area of the wafer 40 between the edge of the metal flat side 12 and the first contour 22. This edge area makes up a significant portion of the area of the wafer 40; However, the entire current from this area can be transported over short distances through the metal foil 30 into the metal body 10, so that the ohmic losses are small and the potential differences are negligible.
  • the first and second contours 22, 24 each have two immediately adjacent contours 26 of the mat thickness G, so-called trench structures.
  • the individual trench structure 26 arranged between the first and second contours 22, 24 is directly adjacent to both contours 22, 24.
  • the mat thickness G is preferably half of the mat thickness M, and in particular G is smaller than the settling height L of the metal flat side 12.
  • the contours 26 with mat thickness G are intended to prevent the propagation of forces parallel to the mat plane, among other things if these forces come from the Deformation of the supporting back structures 22, 24 occurs under force load due to the build-up of negative pressure.
  • the contour widths of the contours 26 can be 1 millimeter, but can also be predetermined to be significantly larger.
  • the user has freedom of choice which he can use to optimize the flexible behavior of his mat 20.
  • initial mat thickness and material inert polymer
  • the user will easily define contours and mat thicknesses based on the present description and will be able to identify the solution with the best results through a simple series of preliminary tests.
  • the brittle wafer 40 is lowered onto the metal flat side 12 with metal foil 30 when the negative pressure is built up using the wafer holder according to the invention so gently and with minimal force that in the inventors' experiments, for example with 300 micrometer thick InP wafers for electrochemical etching, no only wafer is broken anymore, where they all broke before using the invention.

Abstract

The invention relates to a wafer holder for extensively electrically contacting a semiconductor wafer (40) comprising a metal body (10) with a metal flat side (12) offset by the offset height L on the upper side and a gas coupling (16) arranged on the underside, as well as at least one gas channel (14) opening in the metal flat side (12) and leading to the gas coupling (16), wherein the metal body (10) is designed for applying with electrical currents of a magnitude kA, and a flexible mat (20) lying on the metal body (10) and formed from an inert polymer, wherein the mat (20) has a recess for leading through the metal flat side (12) and the edge of the metal flat side (12) is arranged such that it is fixed all around in parallel with the metal flat side (12), the mat (20) has a respective one of at least three mat thicknesses on the side facing away from the metal body (10), along a plurality of closed, mathematically similar, concentric contours (22, 24, 26) and a first contour (22) is designed for contacting the edge region of a wafer (40), and the edge of a metal film (30) lying on the metal flat side (12) is arranged on a second smaller contour (24), and the first and second contours (22, 24) have two respective directly adjacent contours (26). The invention also relates to a use of a wafer holder.

Description

WAFER-HALTERUNG ZUR ELEKTRISCHEN KONTAKTIERUNG SPRÖDER HALBLEITERWAFER SOWIE VERWENDUNG WAFER HOLDER FOR ELECTRICAL CONTACTING BRITTLE SEMICONDUCTOR WAFER AND USE
Die Erfindung betrifft eine Wafer-Halterung zur großflächigen elektrischen und/oder thermischen Kontaktierung eines Wafers mittels Unterdrucks, insbesondere anwendbar in der elektrochemischen oder nasschemischen Prozessierung von Halbleiter-Wafern. The invention relates to a wafer holder for large-area electrical and/or thermal contacting of a wafer using negative pressure, particularly applicable in the electrochemical or wet chemical processing of semiconductor wafers.
Unter der Kontaktierung ist im Sinne dieser Erfindung die Erzeugung eines nicht persistenten kraftschlüssigen Kontakts zwischen einer Flachseite eines Wafers und einer metallischen Elektrode zu verstehen, wobei die metallische Elektrode als guter elektrischer Leiter und/oder als Wärmeleiter verstanden werden soll. Die Kontaktierung soll großflächig in dem Sinne sein, dass die Elektrode den überwiegenden Teil der Waferflachseite kontaktiert, typischerweise sogar fast die gesamte Waferflachseite. For the purposes of this invention, contacting is to be understood as the generation of a non-persistent non-positive contact between a flat side of a wafer and a metallic electrode, whereby the metallic electrode is to be understood as a good electrical conductor and/or as a heat conductor. The contacting should be over a large area in the sense that the electrode contacts the majority of the wafer flat side, typically even almost the entire wafer flat side.
Verschiedene Nachbearbeitungsprozesse für Wafer bedürfen einer großflächigen Kontaktierung. Zu nennen sind hier vor allem Abscheide- bzw. Beschichtungsverfahren und Ätzprozesse. Speziell das großflächige Porenätzen verlangt eine sehr gleichmäßige Kontaktierung der Rückseite, d.h. der dem Elektrolytbad abgewandten Flachseite, des Wafers. Ohne diese gleichmäßige Kontaktierung sind die Ätzergebnisse gewöhnlich nicht kontrollierbar, und das Ätzen zerstört den Wafer lediglich. Various post-processing processes for wafers require large-area contacting. The main ones that should be mentioned here are deposition or coating processes and etching processes. Large-area pore etching in particular requires very uniform contacting of the back, i.e. the flat side of the wafer facing away from the electrolyte bath. Without this uniform contacting, the etching results are usually not controllable and the etching merely destroys the wafer.
Weiterhin ist das Erzeugen gut kontrollierter und gleichmäßiger Temperaturbedingungen für viele chemische Bäder wichtig, vor allem auch, wenn diese bei einer gegenüber Raumtemperatur deutlich erhöhten Temperatur betrieben werden müssen. Furthermore, creating well-controlled and uniform temperature conditions is important for many chemical baths, especially if they have to be operated at a temperature that is significantly higher than room temperature.
Eine zur Kontaktierung von z.B. Silizium (Si)-Wafern gut geeignete Vorrichtung wird bereits in der Druckschrift DE 102013 104469 B4 vorgestellt. Sie basiert auf dem Konzept eines Rahmens mit einem im Rahmeninnern angeordneten, beweglich gelagerten Metall block als Elektrode. Der Rahmen weist eine umlaufende Nut mit einem in der Nut angeordneten O-Ring auf. Der Metallblock seinerseits schließt in jeder Position seines Bewegungsspielraumes gasdicht mit dem Rahmen ab. Wird ein Wafer auf den O-Ring im Rahmen aufgelegt, so kann der Raum zwischen Wafer und Metallblock mit Unterdrück beaufschlagt werden. Dadurch wird der Metallblock an den Wafer herangezogen - ggf. mit einer auf dem Metallblock aufliegenden Metallfolie - und unter sehr geringer Durchbiegung des Wafers in großflächigen Kontakt gebracht. Der Metallblock kann mit großen Stromstärken - mehrere 100 A bis kA - beaufschlagt werden, was vor allem bei Ätzprozessen üblich notwendig ist. A device that is well suited for contacting, for example, silicon (Si) wafers is already presented in the publication DE 102013 104469 B4. It is based on the concept of a frame with a movably mounted metal block arranged inside the frame as an electrode. The frame has a circumferential groove with an O-ring arranged in the groove. The metal block, for its part, forms a gas-tight seal with the frame in every position within its range of movement. If a wafer is placed on the O-ring in the frame, the space between the wafer and the metal block can be subjected to negative pressure. As a result, the metal block is pulled towards the wafer - possibly with a metal foil resting on the metal block - and brought into large-area contact with very little deflection of the wafer. The metal block can be subjected to large currents - several 100 A to kA - which is particularly necessary in etching processes.
Der Transfer dünner monokristalliner Halbleiterschichten ist für viele Anwendungen in der Mikroelektronik, Photovoltaik aber auch Li-Ionen-Akkumulatoren von großem Interesse. Dabei werden vom ursprünglichen Wafer mehrfach Schichten abgetragen, wodurch der Wafer immer dünner und damit bruchanfälliger wird. Zudem sind viele lll-V Halbleiter wie z.B. Indiumphosphid (InP) sehr spröde, so dass selbst dicke Wafer leicht brechen können. Ein probates Mittel zum Separieren einer solchen Halbleiter-Schicht von einem monokristallinen Wafer besteht in einem gesteuerten Ätzangriff in einer vorbestimmten Tiefe des Wafers, beispielsweise durch elektrochemisches Kanalätzen gefolgt von einem Elektropolierschritt zur Ablösung der darüberliegenden durchbohrten Schicht. Hierfür ist die gute Rückseitenkontaktierung des Wafers notwendig und nachgefragt. The transfer of thin monocrystalline semiconductor layers is of great interest for many applications in microelectronics, photovoltaics and also Li-ion batteries. In the process, multiple layers are removed from the original wafer, making the wafer always becomes thinner and therefore more susceptible to breakage. In addition, many III-V semiconductors such as indium phosphide (InP) are very brittle, so that even thick wafers can break easily. An effective means of separating such a semiconductor layer from a monocrystalline wafer consists of a controlled etching attack at a predetermined depth of the wafer, for example by electrochemical channel etching followed by an electropolishing step to remove the overlying drilled layer. For this purpose, good contact on the back of the wafer is necessary and in demand.
Experimente der Erfinder haben indes offenbart, dass sehr spröde Halbleiter-Wafer, insbesondere solche aus InP, gewöhnlich beim Versuch der Kontaktierung mit der vorbeschriebenen Vorrichtung zerbrechen. Dies gilt erst recht, wenn die Ausgangsdicke der InP-Wafer 500 Mikrometer oder weniger beträgt. Als Ursache wird die immer noch zu große mechanische Schlagbelastung angesehen, die sich beim Aufbau des Unterdrucks aus der Annäherung des Metallblocks an den Wafer ergibt. However, experiments by the inventors have revealed that very brittle semiconductor wafers, especially those made of InP, usually break when attempting to make contact with the device described above. This is especially true if the initial thickness of the InP wafers is 500 micrometers or less. The reason is believed to be the still excessive mechanical impact load that results from the metal block approaching the wafer when the negative pressure is built up.
Auf der Suche nach Abhilfe haben sich die Erfinder der Druckschrift US 4 043 894 A aus dem Jahr 1977 zugewandt, in der vordergründig eine Halterung des Wafers mittels Unterdrucks in einem ringförmigen Bereich zwischen zwei Nuten mit O-Ringen und eine mittige elektrische Kontaktierung mittels eines flüssigen Elektrolyten angeregt werden. Diese Ideen sind hier zunächst nicht zielführend, z.B. wegen der großen erforderlichen Stromstärken. Aber die Druckschrift erwähnt gewissermaßen nebenbei in Sp. 2, Z. 59 - Sp. 3, Z. 3: „O-rings provide a plurality of coplanar ridges projecting from the disk upper surface for receiving the wafer. Resilient O-rings are preferred because they provide a good seal to the wafer and can be periodically replaced to insure a consistent seal. However, it is contemplated that ridges could be formed as an integral part of the disk if coplanarity can be maintained. It should be noted that the ridges need not necessarily be concentric or circular as long as that they are continuous or closed-looped and that each continuous ridge has a progressively larger perimeter as they extend towards the outer periphery of the disk surface.” In search of a remedy, the inventors turned to the document US 4,043,894 A from 1977, in which the wafer is primarily held using negative pressure in an annular area between two grooves with O-rings and a central electrical contact is made using a liquid Electrolytes are stimulated. These ideas are initially not effective here, e.g. because of the large current levels required. But the publication mentions, so to speak, in passing in column 2, line 59 - column 3, line 3: “O-rings provide a plurality of coplanar ridges projecting from the disk upper surface for receiving the wafer. Resilient O-rings are preferred because they provide a good seal to the wafer and can be periodically replaced to insure a consistent seal. However, it is contemplated that ridges could be formed as an integral part of the disk if coplanarity can be maintained. It should be noted that the ridges need not necessarily be concentric or circular as long as that they are continuous or closed-looped and that each continuous ridge has a progressively larger perimeter as they extend towards the outer periphery of the disk surface.”
Mit den heute verfügbaren Technologien zur Materialbearbeitung und -Strukturierung ist es möglich, daraus eine Problemlösung abzuleiten. With the technologies available today for material processing and structuring, it is possible to derive a solution to the problem.
Die Erfindung stellt sich die Aufgabe, die großflächige elektrische und/oder thermische Kontaktierung einer Flachseite eines Wafers mittels Unterdrucks auch für sehr spröde Halbleiter-Wafer ohne Bruchgefahr zu realisieren, indem sie eine neue Ausgestaltung einer Wafer-Halterung vorschlägt. The invention sets itself the task of realizing large-area electrical and/or thermal contacting of a flat side of a wafer using negative pressure, even for very brittle semiconductor wafers, without the risk of breakage, by proposing a new design of a wafer holder.
Die Aufgabe wird gelöst durch eine Wafer-Halterung zur großflächigen elektrischen Kontaktierung eines Halbleiter-Wafers umfassend einen Metallkörper mit einer oberseitig um die Absetzhöhe L abgesetzten Metallflachseite und einer unterseitig angeordneten Gaskupplung sowie wenigstens einem in der Metallflachseite offenen, zur Gaskupplung führenden Gaskanal, wobei der Metallkörper zur Beaufschlagung mit elektrischen Strömen der Größenordnung kA ausgebildet ist und eine auf dem Metallkörper aufliegende flexible Matte gebildet aus einem Inertpolymer, wobei die Matte eine Aussparung zur Durchführung der Metallflachseite aufweist und den Rand der Metallflachseite umgebend parallel zur Metallflachseite fixiert angeordnet ist, wobei die Matte auf der dem Metallkörper abgewandten Seite entlang einer Mehrzahl geschlossener, mathematisch ähnlicher, konzentrischer Konturen jeweils eine von wenigstens drei Mattendicken M, R, G aufweist und die Mattendicken mit der Eigenschaft M > R > L > G derart vorbestimmt sind, dass eine erste Kontur der Mattendicke M zur Kontaktierung des Randbereichs eines Wafers ausgebildet ist und auf einer zweiten kleineren Kontur der Mattendicke R der Rand einer auf der Metallflachseite aufliegenden Metallfolie angeordnet ist und die erste und zweite Kontur je zwei unmittelbar benachbarte Konturen der Mattendicke G aufweisen. The object is achieved by a wafer holder for large-area electrical contacting of a semiconductor wafer, comprising a metal body with a metal flat side offset on the top by the offset height L and a gas coupling arranged on the bottom and at least one gas channel open in the metal flat side and leading to the gas coupling, the metal body being designed to be subjected to electrical currents of the order of magnitude kA and a flexible mat resting on the metal body formed from an inert polymer, the mat having a recess for the passage of the metal flat side and surrounding the edge of the metal flat side is arranged fixed parallel to the metal flat side, the mat on the side facing away from the metal body along a plurality of closed, mathematically similar, concentric contours each having one of at least three mat thicknesses M, R, G and the mat thicknesses with the property M > R > L > G are predetermined in such a way that a first contour of the mat thickness M is designed for contacting the edge region of a wafer and on a second smaller contour of the mat thickness R the edge of a metal foil resting on the metal flat side is arranged and the first and second contours each have two immediately adjacent contours of the mat thickness G.
Die Unteransprüche sind auf vorteilhafte Ausgestaltungen der Wafer-Halterung gerichtet. The subclaims are directed to advantageous embodiments of the wafer holder.
Das Inertpolymer kann insbesondere ein Fluoropolymer oder ein Silikon sein. The inert polymer can in particular be a fluoropolymer or a silicone.
Die Mattendicke M kann in einer bevorzugten Ausgestaltung wenige Millimeter (wenige Millimeter können hierbei etwa 1-4 Millimeter sein), insbesondere bevorzugt 2-3 Millimeter, betragen. In a preferred embodiment, the mat thickness M can be a few millimeters (a few millimeters can be about 1-4 millimeters), particularly preferably 2-3 millimeters.
Die Mattendicke M kann bevorzugt zwischen 200 und 300 Mikrometer größer als die Absetzhöhe L der Metallflachseite sein. The mat thickness M can preferably be between 200 and 300 micrometers greater than the settling height L of the metal flat side.
Die Mattendicke G kann insbesondere der halben Mattendicke M entsprechen. The mat thickness G can in particular correspond to half the mat thickness M.
Die erste und die zweite Kontur können jeweils eine Breite von wenigstens 1 Millimeter aufweisen. The first and second contours can each have a width of at least 1 millimeter.
Die Metallfolie kann aus Gold oder Aluminium gebildet sein. The metal foil can be made of gold or aluminum.
Die Dicke der Metallfolie kann insbesondere 30-100 Mikrometer betragen. The thickness of the metal foil can be in particular 30-100 micrometers.
Die Mattendicke R kann zwischen 50 und 150 Mikrometer größer als die Absetzhöhe L der Metallflachseite sein. The mat thickness R can be between 50 and 150 micrometers greater than the settling height L of the metal flat side.
Weiter erfindungsgemäß ist die Verwendung der Wafer-Halterung zur großflächigen elektrischen Kontaktierung von spröden Halbleiter- Wafern, insbesondere von Indiumphosphid- Wafern. Further according to the invention is the use of the wafer holder for large-area electrical contacting of brittle semiconductor wafers, in particular indium phosphide wafers.
Die Grundidee der Erfindung ist darin zu sehen, dass (i) der O-Ring im Rahmen der Vorrichtung gemäß der Druckschrift DE 10 2013 104 469 B4 ersetzt wird durch eine in eine flexible Matte aus einem Inertpolymer integrierte und entlang einer geschlossenen Kontur verlaufende Rückenstruktur und (ii) die Metallflachseite zur Kontaktierung völlig unbeweglich ist. Die Annäherung des auf der Rückenstruktur aufliegenden Wafers an die Metallflachseite - den Metallblock - erfolgt beim Aufbau des Unterdrucks durch den Gaskanal, indem der Wafer unter Nachgeben der flexiblen Rückenstruktur auf die Metallflachseite abgesenkt wird. Bewegt wird also nur die geringe Masse des Wafers selbst und die noch geringere Masse einer oder mehrerer Rückenstrukturen in der flexiblen Matte. Die Kraftbelastung und Durchbiegung des Wafers wird durch die elastische Deformation des Inertpolymers minimiert. The basic idea of the invention can be seen in the fact that (i) the O-ring in the context of the device according to the document DE 10 2013 104 469 B4 is replaced by one that is integrated into a flexible mat made of an inert polymer and runs along a closed contour Back structure and (ii) the metal flat side for contacting is completely immovable. The wafer resting on the back structure approaches the metal flat side - the metal block - when the negative pressure is built up through the gas channel by lowering the wafer onto the metal flat side while the flexible back structure gives way. So only the small mass of the wafer itself and the even smaller mass of one or more back structures in the flexible mat are moved. The force load and deflection of the wafer is minimized by the elastic deformation of the inert polymer.
Das Inertpolymer kommt mit - durch Bestromung - heißem Metall und zumindest außerhalb der äußersten Rückenstruktur auch mit einem Elektrolyten in Kontakt. Es muss deshalb chemisch und thermisch stabil sein. Bevorzugt kommen Fluoropolymere wie z.B. Teflon® oder Silikone als Inertpolymere in Betracht. Eine Matte aus Inertpolymer kann heute z.B. mittels Laserabtrag recht präzise bearbeitet und entlang vorbestimmter Konturen strukturiert werden. Die Strukturierung im Kontext dieser Beschreibung umfasst den Laserabtrag von Polymermaterial zur lokalen Reduzierung der Mattendicke von einem Ausgangswert, z.B. M, auf kleinere Werte, z.B. R und G. The inert polymer comes into contact with - through energization - hot metal and, at least outside the outermost back structure, also with an electrolyte. It must therefore be chemically and thermally stable. Fluoropolymers such as Teflon® or silicones are preferred as inert polymers. A mat made of inert polymer can now be processed quite precisely using laser ablation and structured along predetermined contours. Structuring in the context of this description includes the laser ablation of polymer material to locally reduce the mat thickness from an initial value, e.g. M, to smaller values, e.g. R and G.
Unter einer geschlossenen Kontur versteht diese Beschreibung eine zweidimensionale in sich selbst zurückgeführte Linie in der Mattenebene mit einer vorbestimmten Linienbreite, der Konturbreite. Eine Mehrzahl von Konturen ist auf der Oberseite der flexiblen Matte vorgesehen. Diese Konturen sollen konzentrisch angeordnet und im mathematischen Sinne ähnlich sein, d.h. durch Drehung und/oder Streckung zur Kongruenz gebracht werden können. Den einzelnen Konturen sind erfindungsgemäß unterschiedliche Mattendicken M, R, G zugewiesen, die beispielsweise durch Laserabtrag entlang der Konturen eingerichtet werden. Die Konturen können sich schon deshalb nicht überschneiden, und insbesondere haben alle Konturen auch unterschiedliche Durchmesser. Als unmittelbar benachbart werden zwei Konturen bezeichnet, wenn sie ohne Zwischenraum in der Mattenebene vollständig parallel zueinander verlaufen. Jede Kontur kann maximal zwei unmittelbar benachbarte Konturen aufweisen, nämlich eine kleinere innere, die überall näher am gemeinsamen Zentrum verläuft und eine größere äußere, die überall weiter entfernt vom Zentrum verläuft. This description understands a closed contour to be a two-dimensional, self-recurring line in the mat plane with a predetermined line width, the contour width. A plurality of contours are provided on the top of the flexible mat. These contours should be arranged concentrically and be similar in a mathematical sense, i.e. they should be able to be brought to congruence by rotation and/or stretching. According to the invention, the individual contours are assigned different mat thicknesses M, R, G, which are set up, for example, by laser ablation along the contours. For this reason, the contours cannot overlap, and in particular all the contours have different diameters. Two contours are said to be immediately adjacent if they run completely parallel to each other without any space in the mat plane. Each contour can have a maximum of two immediately adjacent contours, namely a smaller inner one that runs closer to the common center everywhere and a larger outer one that runs further away from the center everywhere.
Im einfachsten Fall sind alle geschlossenen Konturen kreisförmig, d.h. auf der Matte wird eine Anordnung konzentrischer Ringe mit unterschiedlicher Mattendicke realisiert. Es wird jedoch auf den Hinweis der US 4 043 894 A verwiesen, dass die in die Matte integrierten Strukturen auch anders, beispielsweise quadratisch oder sogar sternförmig, ausgestaltet sein können. Dies kann von Vorteil sein für die Bearbeitung nicht-kreisscheibenförmiger Wafer. Hierbei ist hervorzuheben, dass fast alle industriell verwendeten Wafer von der idealen Kreisform abweichen, weil sie zu Zwecken der automatischen Orientierung in Produktionsanlagen mit wenigstens einem Flat versehen sind, d.h. ein Kreisabschnitt am Waferrand ist entfernt worden. Die Konturen der Erfindung können - im Unterschied zu üblichen O-Ringen - dem Randverlauf des Wafers perfekt folgen und somit auch dann eine optimale Gasabdichtung bei maximaler Flächenkontaktierung des Wafers sicherstellen. In the simplest case, all closed contours are circular, ie an arrangement of concentric rings with different mat thicknesses is created on the mat. However, reference is made to the note in US 4,043,894 A that the structures integrated into the mat can also be designed differently, for example square or even star-shaped. This can be advantageous for processing non-circular wafers. It should be emphasized here that almost all industrially used wafers deviate from the ideal circular shape because they are provided with at least one flat for the purposes of automatic orientation in production systems, ie a circular section on the edge of the wafer has been removed. The contours of the invention can - in contrast to conventional O-rings - perfectly follow the edge of the wafer and thus ensure optimal gas sealing with maximum surface contact of the wafer.
Eine der wesentlichen Erkenntnisse der Erfinder aus den Experimenten mit integrierten Rückenstrukturen in einer flexiblen Matte nach Art der US 4 043 894 A ist die, dass sich kein stabiler Unterdrück zwischen Wafer und Metallblock erzielen lässt, wenn die Matte auch nur geringste laterale Verzerrungen aufweist. Solche Verzerrungen können sich aber sowohl beim Fixieren der Matte auf dem Metallblock als auch beim Deformieren der Rückenstrukturen beim Ansaugen des Wafers einstellen, weil bei jeder Deformation auch kleine Kraftkomponenten in Richtung parallel zur Matte wirken, die laterale Verzerrungen nach sich ziehen können. Die Verzerrungen haben dann üblich den Effekt, dass sie die geforderte Planarität der integrierten Rückenstruktur im Kontakt mit dem Wafer aufheben, so dass kein gasdichtes Abschließen mehr möglich ist. One of the inventors' essential findings from the experiments with integrated back structures in a flexible mat in the manner of US 4,043,894 A is that no stable suppression between the wafer and the metal block can be achieved if the mat has even the slightest lateral distortions. However, such distortions can occur both when the mat is fixed on the metal block and when the back structures are deformed when the wafer is sucked in, because with every deformation small force components also act in the direction parallel to the mat, which can result in lateral distortions. The distortions then usually have the effect that they cancel the required planarity of the integrated back structure in contact with the wafer, so that gas-tight sealing is no longer possible.
Zur Vermeidung der unerwünschten Verzerrungen führt die Erfindung hier je zwei den tragenden - zu deformierenden - Strukturen (Konturen mit Mattendicken M, R) unmittelbar benachbarte Konturen der Mattendicke G < R < M ein, die man auch als Grabenstrukturen bezeichnen kann. Ihr Zweck ist die mechanische Entkopplung der tragenden Strukturen von der lateralen Nachbarschaft in der Matte, so dass Kraftkomponenten parallel zur Matte nicht auf diese Nachbarschaft einwirken können. Mit Hilfe dieser Gräben zu beiden Seiten der tragenden Rückenstrukturen ergibt sich eine erhebliche verbesserte Gasdichtigkeit zwischen Wafer und Metallblock; der beaufschlagte Unterdrück ist stabil und beständig. In order to avoid undesirable distortions, the invention introduces two contours of the mat thickness G < R < M which are immediately adjacent to the supporting structures - to be deformed (contours with mat thicknesses M, R), which can also be referred to as trench structures. Their purpose is to mechanically decouple the supporting structures from the lateral neighborhood in the mat so that force components parallel to the mat cannot affect this neighborhood. With the help of these trenches on both sides of the supporting back structures, there is a significantly improved gas tightness between the wafer and the metal block; the negative pressure applied is stable and consistent.
Die Erfindung wird im Folgenden näher erläutert anhand einer beispielhaften Ausführungsform sowie anhand einer Figur. Dabei zeigt: The invention is explained in more detail below using an exemplary embodiment and using a figure. This shows:
Fig. 1 die Skizze eines Schnittbildes senkrecht zu Metallflachseite und aufliegendem Wafer zur Darstellung der erfindungsgemäßen Mattendicken. Fig. 1 is a sketch of a sectional view perpendicular to the flat metal side and the wafer lying on it to show the mat thicknesses according to the invention.
In Fig. 1 ist eine nicht maßstabsgetreue Schnittskizze durch eine beispielhafte Wafer-Halterung gemäß der vorliegenden Erfindung dargestellt. Der Schnitt verläuft dabei senkrecht zur abgesetzten Metallflachseite 12 des Metallblocks 10. Die Metallflachseite 12 ragt um die Absetzhöhe L aus der übrigen Oberseite des Metallblocks 10 heraus und ist in deren Zentrum angeordnet. Sie weist ferner wenigstens eine Öffnung für einen Gaskanal 14 auf, der den Metallblock 10 im Innern durchquert und an der Unterseite des Metallblocks 10 in eine Gaskupplung 16 führt. Die Gaskupplung 16 kann als verschließbarer Hahn ausgebildet sein. Sie dient dem Anschließen einer Vorrichtung zum Ansaugen von Gas von der Metallflachseite 12 her, also dem Beaufschlagen mit Unterdrück. Der Metallblock 10 trägt alle weiteren Komponenten der Wafer-Halterung, insbesondere die flexible Matte 20 aus Inertpolymer. Es ist hier anzumerken, dass die Teile des Metallblocks 10, auf denen die Matte 20 aufliegt, auch durch ein anderes Material ersetzt werden könnten, beispielsweise auch durch ein elektrisch isolierendes Material, etwa einen Kunststoff. In diesem Fall wäre unter der Absetzhöhe L der Metallflachseite 12 sinngemäß der Höhenunterschied zwischen der Metallflachseite 12 und der Auflagefläche der Matte 20 zu verstehen, was auch aus der Fig. 1 leicht ersichtlich ist. 1 shows a sectional sketch, not true to scale, through an exemplary wafer holder according to the present invention. The cut runs perpendicular to the offset metal flat side 12 of the metal block 10. The metal flat side 12 protrudes from the rest of the top side of the metal block 10 by the offset height L and is arranged in its center. It also has at least one opening for a gas channel 14, which passes through the interior of the metal block 10 and leads into a gas coupling 16 on the underside of the metal block 10. The gas coupling 16 can be designed as a lockable tap. It is used to connect a device for sucking in gas from the metal flat side 12, i.e. to apply negative pressure. The metal block 10 carries all other components of the wafer holder, in particular the flexible mat 20 made of inert polymer. It should be noted here that the parts of the metal block 10 on which the mat 20 rests could also be replaced by another material, for example by an electrically insulating material, such as a plastic. In this case, the settling height L of the metal flat side 12 would be understood to mean the difference in height between the metal flat side 12 and the support surface of the mat 20, which can also be easily seen from FIG. 1.
Die Matte 20 weist eine initiale Mattendicke M > L und eine Aussparung zur Durchführung der Metallflachseite 12 auf, d.h. ein zentraler Bereich der Matte 20 ist herausgeschnitten, und die Matte 20 liegt so auf der Oberseite des Metallblocks 10, dass sie den Rand der Metallflachseite 12 umgibt. Die Matte 20 liegt somit parallel orientiert zur Metallflachseite 12 und ist in ihrer Lage fixiert durch geeignete Fixierungselemente wie Schrauben oder Klemmen am Rand der Matte 20 (nicht dargestellt). Die Matte 20 überragt den Rand des Metallblocks 10 üblich nicht. The mat 20 has an initial mat thickness M > L and a recess for the passage of the metal flat side 12, i.e. a central area of the mat 20 is cut out, and the mat 20 lies on the top of the metal block 10 in such a way that it covers the edge of the metal flat side 12 surrounds. The mat 20 is thus oriented parallel to the metal flat side 12 and is fixed in position by suitable fixing elements such as screws or clamps on the edge of the mat 20 (not shown). The mat 20 usually does not protrude beyond the edge of the metal block 10.
Auf der dem Metallblock 10 abgewandten Seite der Matte 20 sind mehrere konzentrische Konturen vorgesehen, die in diesem Beispiel als Kreisringe ausgebildet sind. Entlang dieser Konturen sind mittels Laserabtrag (Laserablation) verschiedene Mattendicken M, R, G eingerichtet, wobei die Relation M > R > L > G mit L als Absetzhöhe der Metallflachseite 12 wesentlich ist. In der Schnittskizze der Fig. 1 sind nur die Querschnitte der herausgearbeiteten Kreisringstrukturen 22, 24, 26 erkennbar. Die Begriffe „geschlossene konzentrische Konturen“ und „Rückenstrukturen, Grabenstrukturen“ werden hier wie auch an anderer Stelle der Beschreibung gern abkürzend synonym verwendet, wobei gemeint ist, dass die dreidimensionalen Strukturen durch Zuordnung einer Mattendicke auf die Konturen entstehen, wenn die Matte 20 mit dem Laser entsprechend bearbeitet wird. On the side of the mat 20 facing away from the metal block 10, several concentric contours are provided, which in this example are designed as circular rings. Different mat thicknesses M, R, G are set up along these contours using laser ablation, whereby the relation M > R > L > G with L as the settling height of the metal flat side 12 is essential. In the sectional sketch of FIG. 1, only the cross sections of the worked out circular ring structures 22, 24, 26 can be seen. The terms “closed concentric contours” and “back structures, trench structures” are often used synonymously here as well as elsewhere in the description, meaning that the three-dimensional structures are created by assigning a mat thickness to the contours when the mat 20 is connected to the Laser processed accordingly.
Die initiale Mattendicke der flexiblen Matte 20 kann vorzugsweise 2 bis 3 Millimeter betragen. Sie kann hiernach zwar überall - d.h. ganzflächig - auf eine vorbestimmte Mattendicke M verringert werden, aber es ist erkennbar zweckmäßig, die Mattendicke M mit der initialen Mattendicke gleichzusetzen. Es ist eine erste geschlossene Kontur 22 mit Mattendicke M für die gasabdichtende Kontaktierung des Wafers 40 vorgesehen. Eine zweite im Durchmesser kleinere und somit weiter innen liegende Kontur 24 mit Mattendicke R dient dem Tragen des Randes einer dünnen Metallfolie 30, die ansonsten auf der Metallflachseite 12 aufliegt und sich über den Rand der Metallflachseite 12 hinaus erstreckt, dabei aber nicht bis zur ersten Kontur 22 reicht. Bevorzugt weist die erste Kontur 22 eine Konturbreite von etwa 1 Millimeter auf, während die zweite Kontur 24 auch breiter als 1 Millimeter ausgelegt sein kann, um eine möglichst große Kontaktfläche zwischen der Metallfolie 30 und dem Rand des Wafers 40 einzurichten. Das übliche „Durchhängen“ der Metallfolie 30 innerhalb der tragenden Kontur 24, das zum Aufliegen der Metallfolie 30 auf der Metallflachseite 12 führt, ist in Fig. 1 zur Vereinfachung der Skizze nicht dargestellt. The initial mat thickness of the flexible mat 20 can preferably be 2 to 3 millimeters. It can then be reduced to a predetermined mat thickness M everywhere - that is, over the entire surface - but it is clearly expedient to equate the mat thickness M with the initial mat thickness. A first closed contour 22 with mat thickness M is provided for the gas-tight contacting of the wafer 40. A second contour 24 with a mat thickness R that is smaller in diameter and therefore further inward serves to support the edge of a thin metal foil 30, which otherwise rests on the metal flat side 12 and extends beyond the edge of the metal flat side 12, but not to the first contour 22 is enough. The first contour 22 preferably has a contour width of approximately 1 millimeter, while the second contour 24 can also be designed to be wider than 1 millimeter in order to establish the largest possible contact area between the metal foil 30 and the edge of the wafer 40. The usual “sagging” of the metal foil 30 within the supporting contour 24, which leads to the metal foil 30 resting on the metal flat side 12 is not shown in FIG. 1 to simplify the sketch.
Weiterhin bevorzugt ist die Mattendicke M zwischen 200 und 300 Mikrometer größer als die Absetzhöhe L der Metallflachseite 12. Anders gesagt überragt die erste Kontur 22 die fest positionierte Metallflachseite 12 um 200-300 Mikrometer im unbelasteten Zustand. Der Metallfilm 30 soll an seinem Rand auf der zweiten Kontur 24 etwas höher liegen als auf der Metallflachseite 12; vorzugsweise ist die Mattendicke R der zweiten Kontur zwischen 50 und 150 Mikrometer größer als die Absetzhöhe L der Metallflachseite 12 eingerichtet. Furthermore, the mat thickness M is preferably between 200 and 300 micrometers greater than the settling height L of the metal flat side 12. In other words, the first contour 22 projects beyond the fixedly positioned metal flat side 12 by 200-300 micrometers in the unloaded state. The edge of the metal film 30 should be slightly higher on the second contour 24 than on the flat metal side 12; The mat thickness R of the second contour is preferably set to be between 50 and 150 micrometers greater than the settling height L of the metal flat side 12.
Vorzugsweise besteht die Metallfolie 30 aus einem guten elektrischen Leitermaterial, bevorzugt aus einem der Elementmetalle Gold oder Aluminium. Die Metallfolie 30 ist bevorzugt zwischen 30 und 100 Mikrometer dick. Der Zweck der Metallfolie 30 ist die Bestromung des Randbereichs des Wafers 40 zwischen dem Rand der Metallflachseite 12 und der ersten Kontur 22. Dieser Randbereich macht einen wesentlichen Anteil der Fläche des Wafers 40 aus; der gesamte Strom aus diesem Bereich kann jedoch über kurze Wege durch die Metallfolie 30 in den Metallkörper 10 transportiert werden, so dass die ohmschen Verluste klein und die Potentialunterschiede vernachlässigbar sind. The metal foil 30 preferably consists of a good electrical conductor material, preferably one of the element metals gold or aluminum. The metal foil 30 is preferably between 30 and 100 micrometers thick. The purpose of the metal foil 30 is to supply current to the edge area of the wafer 40 between the edge of the metal flat side 12 and the first contour 22. This edge area makes up a significant portion of the area of the wafer 40; However, the entire current from this area can be transported over short distances through the metal foil 30 into the metal body 10, so that the ohmic losses are small and the potential differences are negligible.
Die erste und die zweite Kontur 22, 24 weisen erfindungsgemäß je zwei unmittelbar benachbarte Konturen 26 der Mattendicke G auf, sogenannte Grabenstrukturen. Dabei ist die zwischen der ersten und zweiten Kontur 22, 24 angeordnete einzelne Grabenstruktur 26 beiden Konturen 22, 24 unmittelbar benachbart. Vorzugsweise beträgt die Mattendicke G die Hälfte der Mattendicke M, und insbesondere ist G kleiner als die Absetzhöhe L der Metallflachseite 12. Wie bereits erläutert sollen die Konturen 26 mit Mattendicke G die Ausbreitung von Krafteinwirkungen parallel zur Mattenebene unterbinden, u. a., wenn diese Krafteinwirkungen aus der Deformation der tragenden Rückenstrukturen 22, 24 unter Kraftbelastung durch Unterdruckaufbau hervorgehen. Die Konturbreiten der Konturen 26 können 1 Millimeter betragen, aber auch deutlich größer vorbestimmt werden. Hier hat der Nutzer eine Wahlfreiheit, die er zur Optimierung des flexiblen Verhaltens seiner Matte 20 nutzen kann. Je nach Wahl des Nutzers von initialer Mattendicke und Material (Inertpolymer) wird sich der Nutzer basierend auf der vorliegenden Beschreibung ohne Weiteres selbst Konturen und Mattendicken definieren und mittels einer einfachen Reihe von Vorversuchen die Lösung mit den besten Resultaten identifizieren können. According to the invention, the first and second contours 22, 24 each have two immediately adjacent contours 26 of the mat thickness G, so-called trench structures. The individual trench structure 26 arranged between the first and second contours 22, 24 is directly adjacent to both contours 22, 24. The mat thickness G is preferably half of the mat thickness M, and in particular G is smaller than the settling height L of the metal flat side 12. As already explained, the contours 26 with mat thickness G are intended to prevent the propagation of forces parallel to the mat plane, among other things if these forces come from the Deformation of the supporting back structures 22, 24 occurs under force load due to the build-up of negative pressure. The contour widths of the contours 26 can be 1 millimeter, but can also be predetermined to be significantly larger. Here the user has freedom of choice which he can use to optimize the flexible behavior of his mat 20. Depending on the user's choice of initial mat thickness and material (inert polymer), the user will easily define contours and mat thicknesses based on the present description and will be able to identify the solution with the best results through a simple series of preliminary tests.
Das Absenken des spröden Wafers 40 auf die Metallflachseite 12 mit Metallfolie 30 beim Aufbau des Unterdrucks erfolgt mit der erfindungsgemäßen Wafer-Halterung so schonend und minimal mit Kraft belastend, dass in den Experimenten der Erfinder z.B. mit 300 Mikrometer dicken InP-Wafern zur elektrochemischen Ätzung kein einziger Wafer mehr zerbrochen ist, wo vor der Verwendung der Erfindung alle zerbrachen. The brittle wafer 40 is lowered onto the metal flat side 12 with metal foil 30 when the negative pressure is built up using the wafer holder according to the invention so gently and with minimal force that in the inventors' experiments, for example with 300 micrometer thick InP wafers for electrochemical etching, no only wafer is broken anymore, where they all broke before using the invention.

Claims

A N S P R Ü C H E EXPECTATIONS
1. Wafer-Halterung zur großflächigen elektrischen Kontaktierung eines Halbleiter-Wafers (40) umfassend einen Metall körper (10) mit einer oberseitig um die Absetzhöhe L abgesetzten Metallflachseite (12) und einer unterseitig angeordneten Gaskupplung (16) sowie wenigstens einem in der Metallflachseite (12) offenen, zur Gaskupplung (16) führenden Gaskanal (14), wobei der Metallkörper (10) zur Beaufschlagung mit elektrischen Strömen der Größenordnung kA ausgebildet ist, und eine auf dem Metallkörper (10) aufliegende flexible Matte (20) gebildet aus einem Inertpolymer, wobei die Matte (20) eine Aussparung zur Durchführung der Metallflachseite (12) aufweist und den Rand der Metallflachseite (12) umgebend parallel zur Metallflachseite (12) fixiert angeordnet ist, die Matte (20) auf der dem Metallkörper (10) abgewandten Seite entlang einer Mehrzahl geschlossener, mathematisch ähnlicher, konzentrischer Konturen (22, 24, 26) jeweils eine von wenigstens drei Mattendicken M, R, G aufweist und die Mattendicken mit der Eigenschaft M > R > L > G derart vorbestimmt sind, dass eine erste Kontur (22) der Mattendicke M zur Kontaktierung des Randbereichs eines Wafers (40) ausgebildet ist und auf einer zweiten kleineren Kontur (24) der Mattendicke R der Rand einer auf der Metallflachseite (12) aufliegenden Metallfolie (30) angeordnet ist und die erste und zweite Kontur (22, 24) je zwei unmittelbar benachbarte Konturen (26) der Mattendicke G aufweisen. 1. Wafer holder for large-area electrical contacting of a semiconductor wafer (40) comprising a metal body (10) with a metal flat side (12) offset on the top by the setting height L and a gas coupling (16) arranged on the bottom and at least one in the metal flat side ( 12) open gas channel (14) leading to the gas coupling (16), the metal body (10) being designed to be subjected to electrical currents of the order of magnitude kA, and a flexible mat (20) resting on the metal body (10) made of an inert polymer , wherein the mat (20) has a recess for the passage of the metal flat side (12) and is arranged in a fixed manner surrounding the edge of the metal flat side (12) parallel to the metal flat side (12), the mat (20) on the side facing away from the metal body (10). along a plurality of closed, mathematically similar, concentric contours (22, 24, 26) each has one of at least three mat thicknesses M, R, G and the mat thicknesses with the property M > R > L > G are predetermined in such a way that a first contour (22) of the mat thickness M is designed to contact the edge region of a wafer (40) and the edge of a metal foil (30) resting on the metal flat side (12) is arranged on a second smaller contour (24) of the mat thickness R and the first and second Contour (22, 24) each have two immediately adjacent contours (26) of mat thickness G.
2. Wafer-Halterung nach Anspruch 1, dadurch gekennzeichnet, dass das Inertpolymer ein Fluoropolymer oder ein Silikon ist. 2. Wafer holder according to claim 1, characterized in that the inert polymer is a fluoropolymer or a silicone.
3. Wafer-Halterung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Mattendicke M wenige Millimeter, bevorzugt 2 -3 Millimeter, beträgt. 3. Wafer holder according to claim 1 or 2, characterized in that the mat thickness M is a few millimeters, preferably 2 -3 millimeters.
4. Wafer-Halterung nach Anspruch 3, dadurch gekennzeichnet, dass die Mattendicke M zwischen 200 und 300 Mikrometer größer ist als die Absetzhöhe L der Metallflachseite (12). Wafer-Halterung nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die Mattendicke G der halben Mattendicke M entspricht. Wafer-Halterung nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die erste und die zweite Kontur (22, 24) jeweils eine Breite von wenigstens 1 Millimeter aufweisen. Wafer-Halterung nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die Metallfolie (30) aus Gold oder Aluminium gebildet ist. Wafer-Halterung nach Anspruch 7, dadurch gekennzeichnet, dass die Dicke der Metallfolie 30-100 Mikrometer beträgt. Wafer-Halterung nach Anspruch 8, dadurch gekennzeichnet, dass die Mattendicke R zwischen 50 und 150 Mikrometer größer ist als die Absetzhöhe L der Metallflachseite. Verwendung der Wafer-Halterung nach einem der vorangehenden Ansprüche zur großflächigen elektrischen Kontaktierung von spröden Halbleiter-Wafern (40), insbesondere von Indiumphosphid-Wafern. 4. Wafer holder according to claim 3, characterized in that the mat thickness M is between 200 and 300 micrometers greater than the settling height L of the metal flat side (12). Wafer holder according to one of the preceding claims, characterized in that the mat thickness G corresponds to half the mat thickness M. Wafer holder according to one of the preceding claims, characterized in that the first and second contours (22, 24) each have a width of at least 1 millimeter. Wafer holder according to one of the preceding claims, characterized in that the metal foil (30) is made of gold or aluminum. Wafer holder according to claim 7, characterized in that the thickness of the metal foil is 30-100 micrometers. Wafer holder according to claim 8, characterized in that the mat thickness R is between 50 and 150 micrometers greater than the settling height L of the metal flat side. Use of the wafer holder according to one of the preceding claims for large-area electrical contacting of brittle semiconductor wafers (40), in particular indium phosphide wafers.
PCT/DE2023/100639 2022-09-06 2023-09-03 Wafer holder for electrically contacting brittle semiconductor wafers and use WO2024051888A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102022122634.4 2022-09-06
DE102022122634.4A DE102022122634B3 (en) 2022-09-06 2022-09-06 WAFER HOLDER FOR ELECTRICAL CONTACTING BRITTLE SEMICONDUCTOR WAFER AND USE

Publications (1)

Publication Number Publication Date
WO2024051888A1 true WO2024051888A1 (en) 2024-03-14

Family

ID=87931034

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE2023/100639 WO2024051888A1 (en) 2022-09-06 2023-09-03 Wafer holder for electrically contacting brittle semiconductor wafers and use

Country Status (2)

Country Link
DE (1) DE102022122634B3 (en)
WO (1) WO2024051888A1 (en)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4043894A (en) 1976-05-20 1977-08-23 Burroughs Corporation Electrochemical anodization fixture for semiconductor wafers
US6202655B1 (en) * 1996-11-28 2001-03-20 Canon Kabushiki Kaisha Anodizing apparatus and apparatus and method associated with the same
US20050239292A1 (en) * 2002-07-31 2005-10-27 Marc Christophersen Device for etching semicnductors with a large surface area
EP2593586A1 (en) * 2010-07-15 2013-05-22 Centre de Recherche Public - Gabriel Lippmann A chuck, and a method for bringing a first and a second substrate together
US20140251542A1 (en) * 2013-03-08 2014-09-11 John Michael Parsey, Jr. Wafer susceptor for forming a semiconductor device and method therefor
DE102013104469B4 (en) 2012-05-03 2015-08-27 Christian-Albrechts-Universität Zu Kiel Device for the large-area electrical and / or thermal contacting of a wafer
US20170009369A1 (en) * 2015-07-09 2017-01-12 Lam Research Corporation Integrated elastomeric lipseal and cup bottom for reducing wafer sticking
WO2020210804A1 (en) * 2019-04-12 2020-10-15 The Sun Company Llc Porous silicon membrane material, manufacture thereof and electronic devices incorporating same

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4043894A (en) 1976-05-20 1977-08-23 Burroughs Corporation Electrochemical anodization fixture for semiconductor wafers
US6202655B1 (en) * 1996-11-28 2001-03-20 Canon Kabushiki Kaisha Anodizing apparatus and apparatus and method associated with the same
US20050239292A1 (en) * 2002-07-31 2005-10-27 Marc Christophersen Device for etching semicnductors with a large surface area
EP2593586A1 (en) * 2010-07-15 2013-05-22 Centre de Recherche Public - Gabriel Lippmann A chuck, and a method for bringing a first and a second substrate together
DE102013104469B4 (en) 2012-05-03 2015-08-27 Christian-Albrechts-Universität Zu Kiel Device for the large-area electrical and / or thermal contacting of a wafer
US20140251542A1 (en) * 2013-03-08 2014-09-11 John Michael Parsey, Jr. Wafer susceptor for forming a semiconductor device and method therefor
US20170009369A1 (en) * 2015-07-09 2017-01-12 Lam Research Corporation Integrated elastomeric lipseal and cup bottom for reducing wafer sticking
WO2020210804A1 (en) * 2019-04-12 2020-10-15 The Sun Company Llc Porous silicon membrane material, manufacture thereof and electronic devices incorporating same

Also Published As

Publication number Publication date
DE102022122634B3 (en) 2023-09-28

Similar Documents

Publication Publication Date Title
EP1920461B1 (en) Method for producing through-contacts in semi-conductor wafers
DE112012005591B4 (en) Semiconductor device
DE102005024684B4 (en) Semiconductor device
DE3317967C2 (en) Device for achieving heat transfer between a semiconductor wafer and a platen
DE19820878B4 (en) Method of depositing a layer of material on a substrate
DE102011086500B4 (en) Silicon carbide semiconductor device and its manufacturing process
DE1614283C3 (en) Method for manufacturing a semiconductor device
DE1930669C2 (en) Method for manufacturing an integrated semiconductor circuit
DE102006017946B4 (en) silicon carbide semiconductor device
DE102011077764A1 (en) SEMICONDUCTOR DEVICE CONTAINING A CELL RANGE AND EDGE RANGE AND HAVING A STRUCTURE FOR HIGH BREAKTHROUGH VOLTAGE
DE102006042026A1 (en) Device for holding a substrate
DE102005023891A1 (en) A silicon carbide semiconductor device and method of making the same
DE102015210736B3 (en) DEVICE FOR ELECTROSTATIC COUPLING OF A SUBSTRATE WITH A SUBSTRATE CARRIER
DE102017104713A1 (en) CONTROL DEVICE
DE102008017065A1 (en) SiC semiconductor device having outer peripheral structure
DE102020132814B4 (en) FORCE FEEDBACK ACTUATOR FOR A MEMS CONVERTER
EP0335291A2 (en) Method and device of plating pin grid arrays
DE102022122634B3 (en) WAFER HOLDER FOR ELECTRICAL CONTACTING BRITTLE SEMICONDUCTOR WAFER AND USE
DE102005032547B4 (en) Wafer clamp assembly for receiving a wafer during a deposition process
DE102015115809A9 (en) A method of electrodepositing gold on a copper seed layer to form a gold metallization structure
EP2081233A1 (en) Power diode with trench anode contact region
DE102018213735B4 (en) Component and method for producing a component
DE102015113529A1 (en) Method, substrate holding device and processing arrangement
DE102008018742A1 (en) Tool electrode for electrochemical machining device, has semiconductor material including semiconductor substrate with relief-type surface structure, and insulating layer formed along surface structure
DE102014102493A1 (en) Improved disc cell for multiple pressure-contacted semiconductor devices

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23772765

Country of ref document: EP

Kind code of ref document: A1