DD242880A1

DD242880A1 - DEVICE FOR PHOTOLITHOGRAPHIC STRUCTURAL TRANSMISSION

Info

Publication number: DD242880A1
Application number: DD24757183A
Authority: DD
Inventors: Karl-Heinz Kuch
Original assignee: Kuch Karl Heinz
Priority date: 1983-01-31
Filing date: 1983-01-31
Publication date: 1987-02-11

Abstract

Bei einer Einrichtung zur fotolithografischen Strukturuebertragung soll die Aufloesung des optischen Systems durch Anwendung einer Immersionsfluessigkeit erhoeht werden. Aufgabengemaess ist fuer die besonderen Anwendungsbedingungen in der Lithografie, speziell Transport und Wechsel des Bildtraegers, eine Moeglichkeit zur Abdichtung der Immersionsfluessigkeit zu schaffen, welche die erforderliche Handhabung des Bildtraegers nicht beeintraechtigt und den Bildtraeger nicht beschaedigt. Erfindungsgemaess ist der Raum fuer die Immersionsfluessigkeit gegenueber dem Bildtraeger durch ein bewegliches, festes, transparentes optisches Medium abgeschlossen, das durch Druckaenderung der Immersionsfluessigkeit nur waehrend der fotolithografischen Strukturuebertragung mit dem Bildtraeger in Kontakt gebracht und waehrend der Bewegung und des Wechsels des Bildtraegers von diesem abgehoben wird. Fig. 2 a bIn a photolithographic structure transfer device, the resolution of the optical system is to be increased by using an immersion liquid. Taskgemaess is for the particular conditions of use in lithography, especially transport and change of Bildtraegers to create a way to seal the Immersionsfluessigkeit that the required handling of the Bildtraegers not impaired and the Bildtraeger not damaged. According to the invention, the space for the immersion liquid is sealed off from the image carrier by a movable, solid, transparent optical medium, which is brought into contact with the image carrier only during the photolithographic pattern transfer by pressure change of the immersion liquid and is lifted off the image carrier during movement and change of the image carrier , Fig. 2 a b

Description

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Im ersten Ausführungsbeispiel (Fig. 1 a und 1 b) befindet sich vor der Frontlinse 1 eines Projektionsobjektivs 2 eine Immersionsflüssigkeit 3. Diese ist gegenüber der auf dem Koordinatentisch 4 befestigten Halbleiterscheibe 5 durch eine in einer ringförmigen Membran 6 elastisch aufgehängten Glasplatte 7 abgegrenzt.In the first exemplary embodiment (FIGS. 1 a and 1 b), an immersion liquid 3 is located in front of the front lens 1 of a projection objective 2. This is delimited by a glass plate 7 suspended elastically in an annular membrane 6 in relation to the semiconductor wafer 5 fastened on the coordinate table 4.

Über das Rohr 8 ist die Immersionsflüssigkeit 3 mit einer nicht dargestellten Einrichtung zur Druckregelung verbunden. Während des Belichtungsprozesses wird die Glasplatte 7 durch einen erhöhten Druck gegen die Halbleiterscheibe 5 gedrückt (Fig. 1 a).Via the tube 8, the immersion liquid 3 is connected to a device for pressure control, not shown. During the exposure process, the glass plate 7 is pressed against the semiconductor wafer 5 by an increased pressure (FIG. 1 a).

Während der Bewegung des Koordinatentisches 4 mit der Halbleiterscheibe 5 wird die Glasplatte 7 durch Druckminderung der Immersionsflüssigkeit 3 von der Halbleiterscheibe 5 abgehoben (Fig. 1 b).During the movement of the coordinate table 4 with the semiconductor wafer 5, the glass plate 7 is lifted off the semiconductor wafer 5 by reducing the pressure of the immersion liquid 3 (FIG. 1 b).

Beim zweiten Ausführungsbeispiel (Fig.2) ist gegenüber dem ersten Ausführungsbeispiel die in der ringförmigen Membran 6 elastisch aufgehängten Glasplatte 7 durch eine durchgehende transparente Membran 9 ersetzt.In the second exemplary embodiment (FIG. 2), the glass plate 7, which is elastically suspended in the annular membrane 6 and is replaced by a continuous transparent membrane 9, is replaced by the first embodiment.

Analog zum ersten Ausführungsbeispiel zeigt Fig.2a das Ausführungsbeispiel 2 mit angedrückter Membran 9 und Fig.2b während der Bewegung des Koordinatentisches 4 mit abgehobener Membran 9 durch Druckverminderung der Immersionsflüssigkeit 3.Analogously to the first exemplary embodiment, FIG. 2a shows the embodiment 2 with the membrane 9 pressed in, and FIG. 2b during the movement of the coordinate table 4 with the membrane 9 lifted off by reducing the pressure of the immersion liquid 3.

Claims

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Invention claim:

1. A device for photolithographic structure transfer by means of an optical projection lens on a parallel to the image plane gradually moving and preferably at short intervals automatically replaceable image carrier, characterized in that in a demarcated between projection lens and image carrier space, the image carrier by a movable, transparent optical medium is tightly closed, a per se known immersion liquid is approximately the same refractive index, the liquid pressure on the optical medium for unimpeded transport or change of the image carrier is changeable.

2. Device according to item 1, characterized by an elastic film as an optical medium.

3. Device according to item 1 characterized by an elastically mounted plate as an optical medium.

4. Device according to item 1, characterized in that there is a thin liquid film of the same refractive power as the optical medium between the image carrier and the optical medium to avoid star and interference effects. ·

For this 2 pages drawings _:

Field of application of the invention

The invention relates to a device for photolithographic structure transfer by means of an optical projection lens to a parallel to the image plane gradually moving and at short intervals preferably automatically replaceable image carrier, in particular for the production of microelectronic devices.

Characteristic of the known technical solutions

The projection optical structuring of microelectronic circuits requires with increasing the degree of integration an ever higher optical resolution, which in turn depends on the aperture of the projection optics. The increase in the aperture reduces the depth of field and, in connection with the unevenness of the image carrier, leads to technological problems.

By introducing a high refractive immersion liquid between the front lens of the objective and the image carrier, the resolution of the projection optics can be increased without reducing the depth of field. The method known from microscopy (Brockhaus, "ABC der Optik", Brockhaus Verlag Leipzig, 1961 p. 565ff.) Is not transferable to microlithography, since the immersion liquid held by adhesion forces between the image carrier and the front lens in the usual stepwise movement of the A sliding mechanical seal is eliminated because of the risk of damage to the image carrier and because of the high frictional forces that impede an exact positioning of the image carrier.

Object of the invention

The aim of the invention is to increase the resolution of the optical system in photolithographic devices with a per se known immersion liquid.

Explanation of the essence of the invention

The invention has for its object to provide in a photolithographic device a way to seal the immersion liquid, which leads to no sliding contact of the seal with the image carrier and does not affect the image carrier transport and change.

According to the invention, this object is achieved in that in a device for photolithographic structure transfer by means of an optical projection lens through an immersion liquid through on an image carrier, ζ. Β. a photo plate or a semiconductor wafer containing immersion liquid in a closed space; which is sealed relative to the image carrier by a movable, solid, transparent optical medium with the same refractive power, which is pressed during exposure by the pressure of the immersion liquid on the image carrier and lifted during the stepwise movement of the image carrier or its change by negative pressure of the immersion liquid. The transparent optical medium may be an elastic membrane, e.g. B. be a foil or an elastically mounted plate. To avoid scattering and interference phenomena, it is expedient to wet between the solid optical medium and the image carrier, the solid optical medium or the image carrier with a thin film of an immersion liquid of the same refractive index.

embodiment

The invention will be explained below with reference to two illustrated in the drawing embodiment. In the drawing show:

Fig. 1 (1a, 1b): device with a flat elastically mounted plate as a sealing medium Fig.2 (2a, 2b): device with an elastic film as a sealing medium