Speedfam Co Ltd

Other

Speedfam-ipec Co Ltd

Yasuhiro Horiike and Speedfam Co, Ltd.

Michihiko Yanagisawa

Shinya Iida

Yasuhiro Horiike

Chikai Tanaka

Tadayoshi Okuya

Kazuyuki Tsuruoka

Takeshi Sadohara

This invention provides a local dry etching method comprising the step of removing an oxide film formed on the surface of a semiconductor water before unevenness on the semiconductor wafer is removed by scanning the surface of the semiconductor wafer at a controlled relative speed with a nozzle for applying a flow of activated species gas to the surface of the semiconductor wafer. The removal of this oxide film is carried out by widening an etching profile and a scan pitch and making the nozzle speed constant, and then flattening is carried out in the same local dry etching apparatus. For flattening, the nozzle speed is changed for each area according to initial unevenness.

Local dry etching method

To resolve a problem that an etching rate profile is changed by a position of a nozzle relative to a semiconductor wafer and accordingly, at a vicinity of an outer edge of the semiconductor wafer, an accurate machining result is difficult to achieve, gas including activated species produced by plasma is blown from a nozzle locally to a surface of the semiconductor wafer W supported on a wafer table concentrically therewith to thereby remove unevenness on the surface of the semiconductor wafer. In this case, the wafer table is provided with a radius larger than a radius of the semiconductor wafer supported thereby by an outstretched portion to thereby prevent an outer edge from being removed excessively by reflected gas.

Wafer table for local dry etching apparatus

In a local dry etching method, position-thickness data of a semiconductor wafer is previously obtained by measuring the wafer surface, components of position-thickness data shorter than a predetermined spatial wavelength are cut off by filtering and nozzle-wafer relative speed for planarizing the surface is calculated using the filtered data.

To remove nanotopography (unevenness of wavelength: 0.2 mm through 20 mm, wave height: 1 through several hundreds nm) which has already been produced on a surface of a semiconductor wafer which has been regarded as impossible to remove conventionally, a half value width of an etching profile of activated species gas is set to fall in a range equal to or smaller than a wavelength a of nanotopography and equal to or larger than a half thereof. Based on previously measured data of nanotopography, moving speed and locus of injected activated species gas along a surface of a semiconductor wafer are calculated and controlled.

Nanotopography removing method

In a local dry etching method of the invention, a surface of a representative wafer sampled from a lot is test etched, each wafer of which is sliced from the same ingot, and initial data of recesses and projections of which is previously known, recesses and projections of the representative wafer is measured after test etched, an etching profile is derived from the initial data and measured data and then respective wafer surfaces of the lot are etched in condition calculated by using at least the derived etching profile.

A wafer flattening process designed to flatten the entire surface of the wafer including the outer rim of the wafer by inserting dummy data corresponding to the data of the outer rim of the wafer in the data of the outside of the wafer, and a storage medium for the same. An area S is set at an outside position exactly an etching radius r from an outer rim Wc of the wafer Wc ahd the nozzle relative speed at the position-speed data D of points P -1 to P -3 closest to an imaginary line L passing through the point P inside the area S near the outer rim Wc is set to be the same as the nozzle relative speed of the position-speed data D of the point P Due to this, the nozzle spraying the activated species gas G moves as if along the imaginary line L and the portion of the point P is etched flat by superposition of the activated species gas G of the nozzle passing through the points P - to P - the point P and the point P

Wafer flattening process and storage medium

A wafer etching method wherein hydrogen gas, ammonia gas or mixed gas containing one of these gases is added to sulfur hexafluoride gas to suppress the occurrence of white turbidity on the surface of the wafer at the time of etching and to enable high quality mirror polishing of the wafer. In one embodiment, a mixed gas obtained by mixing SF gas G of a bomb and H gas G of a bomb in a predetermined ratio is fed to a discharge tube and a microwave M is generated from a microwave oscillator to cause plasma discharge. Further, the entire surface of the silicon wafer W can be flattened by locally etching the surface of the silicon wafer W by an activated species gas G sprayed from the nozzle portion

Wafer etching method

In the semiconductor wafer manufacturing method of the present invention, a deteriorated layer on the surface of a semiconductor wafer which has been made flat by lapping or polishing is removed by the following dry etching. Plasma which contains a neutral active species is generated within a discharge tube. The neutral active species is separated from the plasma thus generated and is then conveyed to an orifice side of a nozzle portion of the discharge tube. The orifice is opposed to the wafer surface and the nozzle portion moves along the wafer surface while the neutral active species is sprayed from the nozzle orifice toward the wafer surface which is pre-heated. By such dry etching, the deteriorated layer on the wafer surface is removed without the occurrence of any etch pit.

Method for manufacturing a semiconductor wafer

A discharge tube for a local etching apparatus has a portion positioned within a waveguide which is for the generation of plasma, the said portion being tapered so as to be divergent toward an orifice side of the discharge tube. Even in the event a maximum field strength position of a standing wave in the waveguide should be deviated due to a change in microwave transmission characteristic of the material of the discharge tube or a change in the position of a plunger under the influence of heat, the maximum field strength position lies somewhere in the vicinity of a wall surface of the tapered portion, so that a supplied gas is converted to plasma stably in a short time. When the discharge tube is to be cooled, the cooling can be done effectively with a cooling gas which is cooled by adiabatic expansion while passing through the tapered portion.

Discharge tube for a local etching apparatus and a local etching apparatus using the discharge tube

The present invention provides a processing method of outermost periphery edge part of silicon wafer comprising, etching the outermost periphery edge of silicon wafer by activated species gas generated in plasma. The plasma activated species gas can be generated by dissociation of, for example, sulfur hexafluoride gas in a discharge tube . Further, provides a processing apparatus for etching of outermost periphery edge of silicon wafer by means of plasma etching method comprising, a means to hold and rotate a silicon wafer , a container which covers all surface of silicon wafer except a part of outermost periphery edge, a vacuum chamber which contain said container and a plasma generating means

Processing apparatus for etching the edge of a silicon wafer

A wafer flattening system is provided to consecutively and automatically remove the natural oxide film from a wafer and flatten and smooth the wafer so as to improve the surface roughness of the wafer and improve the work efficiency. A step of immersing the wafer in an aqueous solution of hydrofluoric acid of a natural oxide film removing device is performed so as to remove the natural oxide film, then followed by a step of locally etching the surface of the wafer at a local etching apparatus by an activated species gas produced from SF gas to flatten the surface. Then, a step of giving a mirror finish to the wafer surface by a CMP apparatus is performed to smooth it. It is also possible to perform the step of removal of the natural oxide film by spraying the entire surface of the wafer by an activated species gas produced from a mixed gas of CF gas and H gas and possible to perform the step of smoothing by spraying the entire surface of the wafer by an activated species gas produced from a mixed gas of CF gas and O gas.

Wafer flattening system

A corrosion-resistant system and method for a plasma etching apparatus are provided which are capable of reducing a corrosion or erosion phenomenon of a discharge tube, equipment and/or elements in a chamber of the plasma etching apparatus which is used for localized etching. A micro wave M is oscillated from a micro wave oscillator,toward a mixed gas of CF,and O,in a quartz discharge tube,to thereby produce plasma discharge. The micro wave oscillator,is controlled in an on-off manner by means of a pulse generator,, to thereby oscillate a pulsed micro wave M. As a result, it is possible to reduce the erosion of the quartz discharge tube,caused by an active species gas G generated by the plasma discharge. Preferably, a corrosion-resistant oil A is filled in the chamber,for preventing an X-Y drive mechanism,, etc., therein from being corroded or eroded by the active species gas G diffusing in the chamber

Corrosion-resistant system and method for a plasma etching apparatus

A plasma etching method and apparatus are provided in which a distance between an ejection opening (,) in a plasma generator (,) for ejecting an active species gas and a surface of an object to be etched can be changed to thereby shorten the time required for a surface flattening operation and reduce the cost of equipment as well. To this end, the ejection opening (,) of a predetermined diameter is disposed in confrontation with a desired convex of the object to be etched in the form of a wafer (,). The active species gas in the form of an F gas (G) is ejected from the ejection opening (,) to the convex to thereby flatten it through etching. A distance between the ejection opening and the convex is changed by means of a Z drive mechanism (,) to provide an etching area corresponding to an area of the convex, thus performing effective flattening of the wafer (,).

Plasma etching apparatus

A local etching apparatus and local etching method improving the throughput of the local etching apparatus by preheating a discharge tube before ignition of the plasma discharge. The local etching apparatus is provided with a plasma generator,, an alumina discharge tube,, and a heater,. The heater,is constituted by a heating wire,, a power source,for supplying voltage to the heating wire,, and a voltage regulator,for controlling the voltage supplied from the power source,to the heating wire,. Due to this, it is possible to heat the alumina discharge tube,to the desired temperature by the heater,immediately before the plasma discharge by the plasma generator,. As a result, there is no need to wait with the local etching work until the alumina discharge tube,rises in temperature to the desired temperature due to the heat by the plasma discharge, that is, it is possible to perform the local etching work immediately after the plasma discharge.

Local etching apparatus

A wafer flattening process for improving the micro-roughness of a wafer by local etching while maintaining a distance between a plasma discharge location and the wafer surface at a predetermined value. By executing a plasma generating step, SF,gas in a gas cylinder,is fed to the inside of an alumina discharge tube,then plasma discharge of the SF,gas is caused by a plasma generator,to produce an activated species gas G and which is locally sprayed from a nozzle portion,of the alumina discharge tube,to the surface of the silicon wafer W. In this state, by performing a local etching step, the surface of the silicon wafer W is flattened. At this time, the distance from the approximate center of the plasma discharge location to the surface of the silicon wafer W is set to a distance larger than 3000 times the mean free path of the ions in the activated species gas G and smaller than 6000 times. Due to this, the ions in the activated species gas G are extinguished before being sprayed from the nozzle portion,and therefore the surface of the silicon wafer W is etched by only the neutral radicals without being damaged.

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Ayase, Japan

Michihiko Yanagisawa