DE2538450A1 - Etching polycrystalline silicon film with neutral aq. etchant - contg. iodine and fluoride gives reproducible results - Google Patents

Etching polycrystalline silicon film with neutral aq. etchant - contg. iodine and fluoride gives reproducible results

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Publication number
DE2538450A1
DE2538450A1 DE19752538450 DE2538450A DE2538450A1 DE 2538450 A1 DE2538450 A1 DE 2538450A1 DE 19752538450 DE19752538450 DE 19752538450 DE 2538450 A DE2538450 A DE 2538450A DE 2538450 A1 DE2538450 A1 DE 2538450A1
Authority
DE
Germany
Prior art keywords
etchant
etching
iodine
polycrystalline silicon
contg
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
DE19752538450
Other languages
German (de)
Inventor
Josef Briegel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Licentia Patent Verwaltungs GmbH
Original Assignee
Licentia Patent Verwaltungs GmbH
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 Licentia Patent Verwaltungs GmbH filed Critical Licentia Patent Verwaltungs GmbH
Priority to DE19752538450 priority Critical patent/DE2538450A1/en
Publication of DE2538450A1 publication Critical patent/DE2538450A1/en
Withdrawn legal-status Critical Current

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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
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
    • H01L21/321—After treatment
    • H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
    • H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
    • H01L21/32134—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by liquid etching only
    • 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
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
    • H01L21/321—After treatment
    • H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
    • H01L21/32131—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by physical means only
    • H01L21/32132—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by physical means only of silicon-containing layers

Abstract

Polycrystalline Si (I) films are etched using a soln. of an etchant (II) contg. iodine as oxidant and a fluoride as an oxide solubiliser (III) in demineralised water. Pref. (III) is NH4F and (II) is an iodide, esp. KI or NH4I. The process is claimed for etching a (I) film on a SiO2 substrate. It is esp. useful for the prodn. of multi diode targets with (I) islets for 'Vidicon' (RTM) systems and can also be used in the prodn. of MOD semiconductors or CCD structures. The process is reproducible and allows (I) to be etched without attack of photo or electron resist materials. Very fine structures can be etched. The etching soln. has low toxicity and is relatively safe and does not attack SiO2, since it is almost neutral.

Description

~?erfahren zum ätzen von polykristallinem Silizium" Die Erfindung betrifft ein Verfahren zum sitzen von Schichten aus polykristallinem Silizium unter Verwendung eines in demineralisiertem Wasser gelösten Ätzmittels, welches zumindest ein Oxidationsmittel und einen Oxidlöser enthält. ~? Learn about etching polycrystalline silicon "The invention relates to a method for sitting beneath layers of polycrystalline silicon Use of an etchant dissolved in demineralized water, which at least contains an oxidizing agent and an oxide solvent.

In der Halbleitertechnologie liegt häufig die Aufgabe vor, polykristallines Silizium, welches als Schicht auf einem Träger, beispielsweise aus Siliziumdioxid oder monokristallinem Silizium, aufgebracht ist, zu strukturieren oder abzuätzen.In semiconductor technology, the task is often polycrystalline Silicon, which as a layer on a carrier, for example made of silicon dioxide or monocrystalline silicon, is applied, to be structured or etched off.

Hierfür werden üblicherweise stark aggressive Ätzmitte 1 verwendet, welche zumeist aus Gemischen von Salpetersäure, Phosphorsäure, Eisessig und einem geringen Anteil Flußsäure bestehen. Die Gemische können dabei in unterschiedlichen Konzentrationgverhältnissen zur Anwendung kommen.Strongly aggressive etching agents 1 are usually used for this, which mostly from mixtures of nitric acid, phosphoric acid, glacial acetic acid and one a small amount of hydrofluoric acid. The mixtures can be in different Concentration ratios are used.

Die herkömmlichen ätzmittel greifen jedoch die für die Herstellung feinster Strukturen geeigneten ätzmaske, beispielsweise Masken aus Photo- oder Electron-Resist-Materialien, ebenfalls chemisch an und zerstören so die gewünschten Strukturen. Aus diesem Grund muß bei solchen Herstellungsprozessen mit Oxidmasken gearbeitet werden, welche sich als hinreichend widerstandsfähig gegenüber starken Ätzmitteln erwiesen haben.However, the conventional etchants are used for the production etching mask suitable for finest structures, for example masks made of photo or electron resist materials, also chemically and thus destroy the desired structures. For this reason must be used in such manufacturing processes with oxide masks, which have proven to be sufficiently resistant to strong caustic agents.

Allerdings erfordern Oxidinasken einen zusätzlichen Hochtemperaturprozeß und einen weiteren Ätzprozeß, wobei ein zusätzlicher Ätzschwund auftritt und eine für viele Prozesse unbrauchbare Kastenform entsteht.However, oxidinasques require an additional high-temperature process and a further etching process, wherein an additional etch fading occurs and one The result is a box shape that is unusable for many processes.

Auch im Hinblick auf die bei diesem Ätzprozeß verwendeten stark aggressiven Ätzmittel ist die Reproduzierbarkeit nicht gewährleistet, da die erzielten ätzrate stark mit der Zusammensetzung der im Ätzmittel enthaltenen Gemische variieren und auch die Alterung des Ätzmittels das Abtragungsverhalten beeinflußt.Also with regard to the highly aggressive ones used in this etching process Etching agent, the reproducibility is not guaranteed because of the achieved etching rate vary greatly with the composition of the mixtures contained in the etchant and the aging of the etchant also influences the erosion behavior.

Der Erfindung lag daher die Aufgabe zugrunde, ein reproduzierbares Verfahren anzugeben, mit dessen Hilfe Schichten aus polykristallinem Silizium geätzt werden können, ohne daß Photo- oder Electron-Resist-Materialien angegriffen werden. Hierbei soll ein Ätzinittel verwendet werden, welches zumindest ein Oxidationsmittel und einen Oxidlöser enthält.The invention was therefore based on the object of a reproducible Specify method by means of which layers of polycrystalline silicon are etched without attacking photo or electron resist materials. In this case, an etching agent should be used which has at least one oxidizing agent and contains an oxide solvent.

Diese Aufgabe wird erfindungsgemaß dadurch gelöst, daß als Oxidationsmittel Jod und als Oxidlöser ein Fluorid verwendet wird.This object is achieved according to the invention in that as the oxidizing agent Iodine and a fluoride is used as an oxide solvent.

Als Oxidlöser hat sich Ammoniumfluorid besonders bewährt, jedoch sind ähnlich gute Ergebnisse auch mit anderen Fluoriden erreichbar. Zur besseren Auflösung des als Oxidationsmittel dienenden codes ist es zweckmäAig, dem Lösungsmittel, im vorliegenden Fall demineralisiertem Wasser, noch ein Jodid, vorzugsweise KaliumJodid oder Ammoniumåodid, beizufügen. Hierbei muß lediglich eine solche Menge Jodid zugesetzt werden, bis sich alles Jod gelöst hat.Ammonium fluoride has proven to be particularly effective as an oxide solvent, but they are similarly good results can also be achieved with other fluorides. For better resolution of the code serving as oxidizing agent, it is expedient to add the solvent in the present case demineralized water, nor an iodide, preferably potassium iodide or ammonium iodide. In this case, only such an amount of iodide has to be added until all the iodine has dissolved.

Das Konzentrationsverhältnis zwischen Oxidlöser und Oxidationsmittel soll möglichst zwischen 1,5 und 100 liegen, wobei die Jodkonzentration etwa 1 bis 500 g/l, vorzugsweise 5 bis 100 g,l und die Fluoridkonzentration etwa 10 bis 200 g/l betragen kann.The concentration ratio between the oxide solvent and the oxidizing agent should be between 1.5 and 100 if possible, with the iodine concentration about 1 to 500 g / l, preferably 5 to 100 g, l and the fluoride concentration about 10 to 200 g / l.

Die Ätzrate ist abhängig von den Konzentrationsverhältnissen und dem Bewegungsrhytlimus in der Ätzlösung. Eine Änderung der Eigenschaften der ätzlösung infolge Alterung konnte nicht festgestellt werden.The etching rate depends on the concentration ratios and the Rhythm of movement in the caustic solution. A change in the properties of the etching solution due to aging could not be determined.

Die beim Ätzprozeß sich ausbildende Kastenform ist steil und doch nach oben hin verrundet, so daß also der Atzschwund gering bleibt. Dies ermöglicht die Ätzung kleinster Strukturen. Hierbei ist es zweckmäßig, bei Verwendung eines handelsüblichen Positivlackes noch eine Zwischenschicht, z. 3. aus einer Halogenphenylsilanverbindung, auf den Träger aufzubringen.The box shape that forms during the etching process is steep and yet rounded towards the top, so that the etching shrinkage remains low. this makes possible the etching of the smallest structures. It is useful when using a commercially available Positive varnish still has an intermediate layer, e.g. 3. off a halophenylsilane compound to be applied to the support.

Bei Verwendung eines handelsüblichen Negativlackes kann diese Zwischenschicht entfallen. Die Kantensteilheit ist auch durch die Wahl des Konzentrationsverhältnisses und der Ausheiztemperatur, d. h. der Temperatur, bei der der Photolack ausgehärtet wird, zu beeinflussen, und zwar in der Weise, daß die Kante umso steiler wird, åe mehr Oxidlöser im Ätzmittel enthalten ist und je höher die Ausheiztemperatur gewählt wird.When using a commercially available negative varnish, this intermediate layer omitted. The steepness of the edge is also determined by the choice of the concentration ratio and the bakeout temperature, d. H. the temperature at which the photoresist cures will influence, in such a way that the edge becomes steeper, åe the more oxide solvent is contained in the etchant and the higher the bake-out temperature selected will.

Auch die Giftigkeit und Gefährlichkeit der verwendeten Ätzlösung etwa im Hinblick auf Verätzungen ist gering, da der pH-Wert dieser Lösung bei etwa 6 liegt. Die Ätzlösung arbeitet somit annnhernd im neutralen Bereich, obwohl sie eine hohe Fluoridkonzentration aufweist. Dies ist auch der Grund dafür, daß eine Schicht aus polykristallinem Silizium geätzt werden kann, ohne daß darunterliegendes Siliziumdioxid anzegriffen wird.The toxicity and danger of the etching solution used, for example in terms of chemical burns is low as the pH of this solution is around 6 lies. The etching solution works almost in the neutral range, although it is a has a high fluoride concentration. This is also the reason for having a layer from polycrystalline silicon can be etched without the underlying silicon dioxide is attacked.

Eine besonders vorteilhafte Anwendung findet das Verfahren bei der Herstellung von Nultidiodentargets mit Poly-Silizium-Inseln für Vidikon-Systeme. Aber auch bei anderen Atzprozessen, etwa im Zusammenhang mit der Herstellung von MOS-Halbleitern oder COD-Strukturen oder bei der Ätzung elektronenstrahlbelichteter Strukturen, l?-ißt sich das Verfahren mit Erfolg anwenden.The method finds a particularly advantageous application in Manufacture of multi-diode targets with poly-silicon islands for Vidikon systems. But also in other etching processes, for example in connection with the production of MOS semiconductors or COD structures or when etching electron beam exposed Structures, the procedure can be used with success.

Claims (3)

Patentans#rüche Patent claims Verfahren zum Ätzen von Schichten aus polykristallinem Silizium unter Verwendung eines in demineralisiertem Wasser gelösten Ätzmittels' welches zumindest ein Oxidationsmittel und einen Oxidlöser enthalt, dadurch gekennzeichnet, daß als Oxidationsmittel Jod und als Oxidlöser ein Fluorid verwendet wird.Process for etching layers of polycrystalline silicon underneath Use of an etchant dissolved in demineralized water which at least Contains an oxidizing agent and an oxide solvent, characterized in that as Oxidizing agent iodine and as oxide solvent a fluoride is used. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß als Oxidlöser Ammoniumfluorid verwendet wird.2. The method according to claim 1, characterized in that the oxide solvent Ammonium fluoride is used. 3. Verfahren nach Anspruch 1 oder Anspruch 2, dadurch gekennzeichnet, daß dem Ätzmittel ein Jodid, vorzugsweise EaliumJodid oder Lmmoniumåodid, zugesetzt wird. 3. The method according to claim 1 or claim 2, characterized in that that an iodide, preferably Ealiumiodid or Lmmoniumåodid, is added to the etchant will. 40 Verfahren nach einem der Ansprüche 1 bis 3, gekennzeichnet durch die Anwendung des Verfahrens bei einer Schicht aus polykristallinem Silizium, welche auf einen Träger aus Siliziumdioxid aufgebracht ist.40 The method according to any one of claims 1 to 3, characterized by the application of the method to a layer of polycrystalline silicon, which is applied to a carrier made of silicon dioxide.
DE19752538450 1975-08-29 1975-08-29 Etching polycrystalline silicon film with neutral aq. etchant - contg. iodine and fluoride gives reproducible results Withdrawn DE2538450A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19752538450 DE2538450A1 (en) 1975-08-29 1975-08-29 Etching polycrystalline silicon film with neutral aq. etchant - contg. iodine and fluoride gives reproducible results

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19752538450 DE2538450A1 (en) 1975-08-29 1975-08-29 Etching polycrystalline silicon film with neutral aq. etchant - contg. iodine and fluoride gives reproducible results

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DE2538450A1 true DE2538450A1 (en) 1977-03-10

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0036113A1 (en) * 1980-03-17 1981-09-23 International Business Machines Corporation Solution for dissolving noble metal alloys which include tin and re-work method of removing said alloys from a substrate
WO1994014188A1 (en) * 1992-12-16 1994-06-23 Semilab Félvezetö Fizikai Laboratórium Rt. Method for chemical surface passivation for in-situ bulk lifetime measurement of silicon semiconductor material

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0036113A1 (en) * 1980-03-17 1981-09-23 International Business Machines Corporation Solution for dissolving noble metal alloys which include tin and re-work method of removing said alloys from a substrate
WO1994014188A1 (en) * 1992-12-16 1994-06-23 Semilab Félvezetö Fizikai Laboratórium Rt. Method for chemical surface passivation for in-situ bulk lifetime measurement of silicon semiconductor material

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