DD300709A7

DD300709A7 - Process for the deposition of thin and thinnest layers

Info

Publication number: DD300709A7
Application number: DD33817690A
Authority: DD
Inventors: Hermann Mai; Thomas Gantz
Original assignee: Akad Wissenschaften Ddr
Priority date: 1990-02-27
Filing date: 1990-02-27
Publication date: 1992-07-09
Also published as: DE59102979D1; EP0445897B1; EP0445897A1

Abstract

Die Erfindung betrifft ein Verfahren zur Abscheidung dünner und dünnster Schichten mittels LPVD. Objekte, auf die sich die Erfindung bezieht, sind LPVD-Anlagen zur Herstellung dünner und dünnster Schichten, insbesondere in den Gebieten der Röntgenoptik und der Mikroelektronik. Erfindungsgemäß werden bei dem Verfahren zur Abscheidung dünner und dünnster Schichten mittels LPVD Targets mit gekrümmter Oberfläche eingesetzt, und es erfolgen eine Relativbewegung von Laserstrahlfokus und Targetoberfläche, eine Verkippung der Symmetrieachse der Plasmafackel (Strahlachse) und der Substratnormalen gegeneinander durch entsprechende Target- und/oder Substratbewegung und die Targetbewegung durch X-Y-Verschiebung mittels Manipulator von außerhalb des Rezipienten und eine damit gekoppelte erzwungene Bewegung in Z-Richtung z.B. durch Schablone, die die infolge X-Bewegung hervorgerufene Abweichung der Targetoberfläche aus dem Laserstrahlfokus kompensiert. Fig.1The invention relates to a method for depositing thin and thinnest layers by means of LPVD. Objects to which the invention relates are LPVD systems for producing thin and thinnest layers, in particular in the fields of X-ray optics and microelectronics. According to the invention, in the method for depositing thin and thinnest layers by means of LPVD targets with a curved surface are used, and there is a relative movement of the laser beam focus and target surface, a tilt of the axis of symmetry of the plasma torch (beam axis) and the substrate normal against each other by appropriate target and / or substrate movement and the target movement by XY displacement by manipulator from outside the recipient and a coupled forced movement in the Z direction, for example by template, which compensates for the deviation of the target surface caused by X-movement from the laser beam focus. Fig.1

Description

Ausfflhrungsbelipiel

Der schernatische Aufbau der verbesserten LPVD-Anordnung ist in Fig. 1 dargestellt. Beim Beschichtungsprozeß trifft der Laserstrahl A unter dem Winkel Θ auf die gekrümmte Targetoberfläche B (Zylindergeometrie, d. h. Krümmung in X-Z-Ebene). Während der Beschichtung wird der Winkel Θ (Neigung von Laserstrahl A gegen die Normale C des jeweils emittierende ι Target-Oberflächenelementes) konstantgehalten. Der Laserstrahlfokus D wird gleichfalls ortsfest im Punkte Xi₁Yt, Z₁ wälrond der Beschichtung gehalten. Zur Richtungsänderung von C gegenüber der Substratnormalen E wird das Target geradlinig in X-Ftichtung verschoben. Die Krümmung der Oberfläche bedingt eine entsprechende Richtungsänderung von C in X-Z-Ebene und damit eine Änderung der Neigung gegen die Substratnormale bzw. eine Änderung des Auftreffortes der Plasmawolke auf dem Substrat. Zur Verhinderung einer Abweichung des Laserstrahlfokus D aus der Targetoberfläche erzwingt gleichzeitig eine Schablonenführung F die Ortskorrektur der beschossenen Targetoberflächenzone in Z-Richtung. Damit wird es möglich, bei konstantgehaltenen Verdampfungsbedingungen den Schnittpunkt von C mit der Substratoberfläche längs der Substratlängsachse G zu führen und eine gleichmäßige Schichtabscheidung in dieser Richtung zu erzielen. Zur Erreichung eines gleichmäßigen Materialabtrages an der Targetoberfläche und zur Vermeidung von Kraterwallausbildung wird das Target in Y-Richtung verschoben, sodaßsich Im Gesamtprozeß einezeilenförmigeAbrasterungderTargetoberflächeergibt. Zur Erzielung einer gleichmäßigen Schichtabscheidung in Substratquerrichtung wird entwederThe sheared structure of the improved LPVD arrangement is shown in FIG. During the coating process, the laser beam A strikes the curved target surface B at an angle Θ (cylinder geometry, ie curvature in the XZ plane). During the coating, the angle Θ (inclination of laser beam A against the normal C of the respectively emitting target surface element) is kept constant. The laser beam focus D is also held stationary at the points Xi ₁ Yt, Z ₁ wälrond the coating. To change the direction of C with respect to the substrate normal E, the target is moved in a straight line in the X-direction. The curvature of the surface causes a corresponding change in direction of C in the XZ plane and thus a change in the inclination against the substrate normal or a change in the impact of the plasma cloud on the substrate. To prevent a deviation of the laser beam focus D from the target surface, a template guide F simultaneously forces the position correction of the bombarded target surface zone in the Z direction. This makes it possible, with the evaporation conditions kept constant, to guide the point of intersection of C with the substrate surface along the substrate longitudinal axis G and to achieve a uniform layer deposition in this direction. To achieve a uniform removal of material at the target surface and to avoid cratering wall formation, the target is displaced in the Y-direction, so that in the overall process a row-shaped rastering of the target surface results. To achieve uniform layer deposition in the transverse direction of the substrate, either

a) das Substrat um die Z-Richtung in Rotation versetzt und die Bahngeschwindigkeit des gerade zu beschichtenden Flächenelements mit der Pulsrate des Lasers synchronisiert odera) the substrate is rotated about the Z direction and the path velocity of the surface element to be coated is synchronized with the pulse rate of the laser or

b) das Substrat in Y-Rnhtung verschoben bzw. geschwenkt.b) the substrate is displaced or pivoted in Y-direction.

Claims

A method for depositing thin and thinnest layers by means of LPVD, characterized in that the target surface (B) is curved, a relative movement of steel focus (D) and target surface (B), tilting of the axis of symmetry of the plasma torch (beam axis) and the substrate normal (E ) against each other by appropriate target and / or substrate movement and the target movement by XY displacement by means of manipulator from outside the recipient and a coupled forced movement in the Z direction, which caused by X movement deviation of the target surface (B) from the beam focus ( D) compensated, done.

2. The method according to claim 1, characterized in that the forced movement in the Z direction is achieved by stencil.

For this 1 page drawing

Field of application of the invention

The invention relates to the field of optics, in particular X-ray optics, and microelectronics. It is used in LPVD plants for the production of thin and thinnest layers.

Characteristic of the known state of the art

It is known to deposit thin layers on a substrate in an LPVD system (A.D. Achsaljan, S.W. Gaponow, S.A. Gusew et al., Journ., Techn. Rz (russ.) 54 [1984] 7S5). In this case, the substrate as well as the target, which has a (flat) planar surface, are arranged in an HV or a UHV-container. The location and direction of the reference axes or surface normals of the basic units essentially determine the result of the layer deposition process. The incident at an angle Θ against the normal of the particular target surface element (A to be evaporated zone) laser beam is focused by a lens located in the beam path so that the focal spot is formed at the location of the zone to be evaporated. From the local place, a plasma cloud is then emitted in photon bombardment into the solid angle ΔΩ whose central axis A is parallel to the normal of the relevant target surface element. The plasma particles fly onto the substrate facing the target, whose surface normal also lies parallel to A. At the substrate surface, the incoming plasma particles condense and form the desired thin layer. A shortcoming of this method is that it results in a location-dependent deposition rate and thus a location dependence of the thickness of the deposited layer on the substrate surface. The cause of the defect is that changes in the emission directional characteristic of the plasma cloud, the integral Teilchefluß for defined distances from the emitting target surface element with the distance perpendicular to the central axis A.

Object of the invention

The object of the invention is to provide a method for depositing thin and thinnest layers by means of LPVD, which does not result in a location-dependent deposition rate and thus no location-dependent thickness of the deposited layer on the substrate surface.

Explanation of the essence of the invention

The invention has for its object to provide a method for depositing thin and thinnest layers by LPVD, boi the integral particle flow for defined distances from the emitting target surface element does not change with the distance perpendicular to the central axis A. According to the invention the object is achieved in that the target surface is curved, a relative movement of the laser beam focus and target surface, a tilt of the axis of symmetry of the plasma torch (beam axis) and the substrate normal against each other by appropriate target and / or substrate movement and the target movement by XY displacement by means of manipulator from outside the recipient and a coupled forced movement in Z-direction eg done by stencil. This compensates for the deviation of the target surface from the laser beam focus due to X movement. A significant advantage of this method is that there is no local dependence of deposition rate and layer thickness and thus a uniform coating and large-area substrates is possible. Other advantages are the simplistic possibility of movement of target and substrate against each other and the favorable construction possibility for UHF systems, since no transmission of combined tilt and rotation of außrhalb into vacuum and no arrangement of coils, etc. in UHV are necessary.