A plasma processor comprising a plasma generating chamber which has a plasma outflow port, an evacuated plasma processing chamber which receives therein a member to be processed, such as a semiconductor substrate, and coaxial magnet means to form coaxial magnetic fields for transporting plasma from the plasma outflow port of the plasma generating chamber to the member to be processed, the distance between the plasma outflow port and the member to be processed being made shorter than the mean free path of gas remaining in the plasma processing chamber.
A radio frequency and a static electric field are superposedly applied to a low pressure gas to generate a gaseous plasma and to drive ions of selected polarity in a predetermined direction. The processing chamber is pre-evacuated to a sufficiently high vacuum, and an etching gas is introduced into the chamber to be rendered to a low pressure at which the mean free path of the ions is sufficiently long. The pressure of the etching gas may range from the order of 10.sup.-2 Torr to several Torr for etching silicon, using a silicon oxide as a mask material. This method improves the treating accuracy, especially minimizes the amount of side etch, as compared with the conventional plasma etching, and reduces the surface damage when compared with the known ion beam etching.
A microwave plasma etching method and apparatus for performing substantially anisotropic etching to form micropatterns on IC substrates. A microwave power source creates a plasma from a gas with a relatively low pressure such as 10.sup.-3 to 10.sup.-4 Torr, so that the mean free path of the gas molecules exceeds the dimensions of the etching apparatus. A magnetic field is generated in a plasma generating chamber, a reaction chamber where in the substrate is mounted and a connecting chamber. The plasma discharge is enhanced by a cyclotron resonance magnetic field intensity corresponding to the frequency of the microwave power applied to the plasma chamber. The magnetic field creates a magnetic mirror which prevents the electrons in the plasma from entering into the reaction chamber so as to eliminate the generation of free radicals in which the reaction chamber which adversely affect the anisotropic etching ability.
An embodiment of the present invention is a plasma system that comprises a main coil with a flattened side and a capacitor in parallel that form a tuned circuit with radio frequency energy coupled to it through a radio frequency match by a generator. A process chamber with a quartz window and containing a low pressure gas is adjacent to the flat side of the main coil and a two-dimensional planar plasma in the shape of a circular disk is ignited and maintained by a high rate of change of the current flowing in the main coil. An electrode positioned in the chamber opposite to the window is used for attaching a semiconductor wafer for processing and a potential applied to the electrode independently controls the ion energy of ions attracted and accelerated out of the plasma.
Substrates are disposed in a reaction chamber having a gas inlet and a gas outlet and a mixture gas containing at least a semiconductor material gas and a carrier gas is introduced into the reaction chamber in such a state in which a gas in the reaction chamber is exhausted therefrom. An electromagnetic field is applied to the mixture gas to ionize it into a mixture gas plasma in the reaction chamber, by which a semiconductor material is deposited on each substrate. In this case, the semiconductor material thus deposited on each substrate becomes a non-crystalline semiconductor by holding the atmospheric pressure in the reaction chamber below 1 atm and maintaining the substrate at a temperature lower than a temperature at which the semiconductor material on the substrate becomes crystallized. The reaction chamber is provided with a gas ionizing region on the side of the gas inlet and a semiconductor depositing region on the side of the gas outlet. In the gas ionizing region, the mixture gas is ionized by a high-frequency electromagnetic field having a high alternating frequency. The mixture gas plasma thus formed in the gas ionizing region is passed into the semiconductor depositing region, in which the substrates are each placed and deposited with the non-crystalline semiconductor layer.
A "planar" type plasma-etching apparatus wherein one electrode is a metallic mesh electrode, while the other electrode is a metallic plate electrode, and wherein a work piece is placed outside the mesh electrode. This apparatus has the advantage that a work piece having a large area can be etched uniformly over its whole surface.
