JPS62120476A - Method and apparatus for photochemical reaction processing - Google Patents

Abstract

PURPOSE:To execute photochemical reaction processing effective for flattening of a device by self-alignment by diagonally irradiating light of parallel luminous fluxes on a substrate in a gaseous atmosphere and relatively rotating the above- mentioned light and the substrate. CONSTITUTION:The light is irradiated from a light source 1 via an optical system 2 and incident window 4 on the desired part on the surface of the substrate 5 in a reaction cell 3 in which the desired gaseous atmosphere is maintained by a gas supply system 10 and exhaust gas system 11, by which the substrate is subjected to the processing based on the photochemical reaction. The above-mentioned light in the above-mentioned photochemical reaction processing method is made into parallel luminous fluxes and such light is diagonally irradiated on the above-mentioned substrate 5 attached via a rotary stage 8 and a heater 9 to an inclined stage 7 on an X-Y stage 6 for position adjustment. The above-mentioned substrate is further rotated around the axis perpendicular thereto as the axis of revolution relatively with the above-mentioned light by the above-mentioned rotary stage 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a processing method and apparatus using photochemical reactions used in the manufacturing process of electronic devices.

[Conventional technology]

Optical process technologies such as photo-CVD and photo-etching that utilize photochemical reactions in the LSI manufacturing process are potential candidates for technologies that can meet the demands for lower temperatures, less damage, and simplification of processes associated with higher integration of LSIs. Attention has been paid.

Among these, the simplification of patterning that eliminates the need for a resist process is one of the most promising forms of application to future LSI processes.

Such an example was proposed in ``Laser annealing apparatus'' in Japanese Patent Application Laid-open No. 57-26445, and an example of experimentally demonstrated laser etching is in ``Abstract of the 16th Concave Element Materials Conference J (1984, Kobe). It is described from page 441 onwards.

[Problem that the invention seeks to solve]

However, in conventional resist I/less patterning technology using optical processes, it is necessary to pattern the irradiated light through a mask and transfer it onto the substrate.
Similar to the lithography step of the normal resist process,
It is necessary to make minute adjustments. For this reason, the required level of optically related technology cannot be alleviated even by conventional optical processes, and this is one of the factors that delays the introduction of optical processes. Moreover, with the advancement of photochemical reactions and the miniaturization of devices, the wavelength of the light source for optical processes tends to become shorter, and this may even lead to an increase in the level of technology required for optical system-related technology. is working. For this reason, in the optical process, we have moved away from the conventional patterning technology, which relies on mask pattern transfer, and have introduced some form of self-line technology that utilizes the pattern on the substrate during the process. It is necessary to significantly lower the technical level.

An object of the present invention is to solve such problems and to provide a photochemical reaction processing method and processing apparatus that are highly effective in planarizing devices using Selfa Line.

[Means for solving problems]

A photochemical reaction processing method according to the first aspect of the present invention, in which a desired part of the surface of a substrate placed in a gas atmosphere is irradiated with light to perform processing based on a photochemical reaction, in which the light is converted into a parallel beam of light. The light beam is irradiated obliquely onto the substrate, and the light nq is rotated relative to the substrate with an axis perpendicular to the substrate serving as a rotation axis.

A second configuration of the present invention includes a light source, a processing cell that introduces light from the light source onto the substrate through an entrance window and holds the substrate in a gas atmosphere in which a photochemical reaction is caused by the light irradiation; and an optical system that converts light from the light source into parallel light and guides it to a desired location on the substrate surface through the entrance window, wherein the parallel light is tilted with respect to a vertical axis of the substrate surface. It is characterized by comprising means for holding the substrate so as to irradiate its surface, and rotating means for rotating the substrate about the vertical axis.

[Effect]

According to the configuration of the present invention, the irradiation light for inducing a photochemical reaction is made into parallel light and is made obliquely incident on the substrate surface.

Assuming that this substrate already has a pattern of protrusions and recesses due to the drawing process, the rectilinear nature of light causes a shadow on the substrate where the light does not hit the concave portions. There is a difference in how the photochemical reaction occurs on the substrate surface between this shadowed area and the area irradiated with light. Furthermore, the selectivity of this reaction naturally occurs in Cellufaline.

In the present invention, by further rotating (precession) the direction of incidence of the irradiation light onto the substrate around the vertical axis of the substrate,
The self-aligned selectivity of this photochemical reaction is further emphasized or modified. In other words, near the bottom of a deep trench or via hole, light is not always irradiated due to this precession, but the shadow part G1 formed above the bottom or, for example, at a step caused by wiring, is affected by this precession. It occurs at a certain time in the cycle of movement, and the light hits the pond during that time, and the flat part is always hit by light as usual.The difference in the irradiation integral time due to the difference in the location near this step, that is, the photochemical reaction. As described below, the difference in amount has an extremely effective effect on flattening, which is important for microdevices, such as improving step coverage and filling via holes.

That is, in the case of photo-etching, only the convex portions of the substrate surface are flattened by etching and soching, since no etching occurs in the shadowed portions.

Next, if a film formation process is performed at the same time in combination with this photoetching, buried film formation is possible.

In this case, it is not necessary to use special effects of light for film formation.

Furthermore, if we utilize the photo-elimination phenomenon in which the reactive species of a photochemical reaction are desorbed from the substrate surface by light, the photochemical reaction will be suppressed in areas with a high amount of light irradiation, contrary to these examples. Since the reaction proceeds in these parts, the thermochemical reaction process can be limited to only four parts by irradiation with light. Therefore, in combination with film formation technology, buried film formation becomes possible.

〔Example〕

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. Light emitted from a light source 1 consisting of an ultraviolet laser is converted into parallel light having a required beam diameter by an optical system 2, and the parallel light is made to enter a substrate 5 through an entrance window 4 of a reaction cell 3. Since this incident light is made into parallel light having a uniform intensity distribution, the optical system 2 does not require an ultra-precise optical system or an alignment mechanism of a lithography stepper, and may have an extremely simple configuration.

The tilt angle of the substrate 5 is set by a tilt stage 7 so that the incident light has a predetermined angle of incidence. Next, a rotation stage 8 allows the substrate 5 to be rotated during the process. Further, since the substrate can be mounted on a heater 9 and heated, an XY stage 6° inclined stage 7, a rotary stage 8. The XY stage 6 is used to correct the horizontal movement of the center of the substrate due to the operation of the tilting stage 7 with respect to the incident light.

Furthermore, this reaction cell 3 is connected to a gas supply system 10 that supplies a gas that induces a photochemical reaction and an exhaust gas treatment system 11.

Hereinafter, an example of application to a specific process will be described in detail.6 FIG. 2 is a cross-sectional view of a substrate when the present invention is applied to via hole embedding of W. In this case, a via hole 22 is opened in the substrate 5 having the lower layer A wiring 21 covered with an insulating film 23 and filled with W.

Normally, WF6 and H2 gas are supplied from the gas supply system 10 to the reaction cell 3 and W is embedded using the reduction reaction of A, but in that case, the thickness of the W that can be embedded is very thin. It cannot be used for filling via holes with large aspect ratios.

In contrast, in this example, instead of a process with substrate selectivity such as a reduction reaction, ordinary thermal CVD using only WF6 is performed, and in addition, CF4 gas for etching W is supplied from the gas supply system 10. At the same time, A and F excimer lasers are used as light source 1 to suppress CVD of W in areas other than the via hole by photo-etching reaction, and deeply embed W in the self-line only in the shadowed via hole area. be able to.

The cross-sectional shape of the embedded metal 24 corresponds to the shadow part determined by the angle of inclination θ between the incident light 25 and the surface of the substrate 5, and even for via holes with high aspect ratios, it does not interfere with post-processing. It can be embedded deep enough to not cause

Note that depending on the wavelength of the light source 1, optical CVD of WF6 may also occur, but in this example, even in that case, the CV of W in the flat portion
To prevent D from occurring, the concentration of the etching gas is set to several Torr.
It is set as high as r.

Although the case where optical etching and batch thermal CVD are combined has been described above, the object to which the present invention is applicable is not limited to this example, and many modifications of the structure are possible.

For example, it can be applied to an etch bag for an insulating film where unevenness occurs on the underlying metal wiring. Further, if the photo-darkening effect on adsorbed species is utilized as a photochemical reaction, it is still possible to embed viapoles in combination with thermal CVD.

Also, instead of the thermal CVD used for film formation in the above explanation,
Physical deposition techniques such as evaporation, sputtering, and MBE may also be used.

Furthermore, the light source is not limited to a laser, and of course an ultraviolet lamp, plasma light emission, etc. that can induce a photochemical reaction can be used. Moreover, instead of rotating the substrate, an optical system may be used that irradiates the substrate with the irradiation light while precessing the irradiation light. Further, photochemical reactions can be applied to modification processing such as laser oxidation.

〔Effect of the invention〕

As explained above, according to the present invention, by irradiating photochemical reaction-inducing light obliquely onto an uneven substrate, it is possible to construct an extremely simple optical system that takes advantage of the difference in the integrated light irradiation amount to the uneven parts. Regardless, Selfaline provides a processing method and processing apparatus that are particularly effective for flattening devices.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram explaining one embodiment of the present invention, and FIG.
The figure is a sectional view of a substrate to which the present invention is applied. 1... Light source, 2... Optical system, 3... Reaction cell, 4
...Incidence window, 5...Substrate, 6...X-Y stage, 7...Tilt stage, 8...Rotation stage, 9...
... Heater, 10 ... Gas supply system, 11 ... Exhaust gas treatment system, 21 ... A wiring, 22 ... Via hole,
23... Insulating film, 24... Embedded metal, 25
...Incoming light.

Claims (2)

[Claims] (1) In a photochemical reaction processing method in which a desired part of the surface of a substrate placed in a gas atmosphere is irradiated with light to perform processing based on a photochemical reaction, the light is converted into a parallel beam of light and directed diagonally onto the substrate. A photochemical reaction processing method characterized by irradiating and relatively rotating the substrate and the light using an axis perpendicular to the substrate as a rotation axis. (2) a light source, a processing cell that introduces light from the light source onto the substrate through an entrance window and holds the substrate in a gas atmosphere that causes a photochemical reaction by irradiation with the light; In a photochemical reaction processing apparatus, the parallel light is tilted with respect to a vertical axis of the substrate surface and irradiates the substrate surface. A photochemical reaction processing apparatus comprising means for holding a substrate in a holder and rotation means for rotating the substrate around the vertical axis.