Process for manufacturing a semiconductor device

#1. Field of the Invention

#The present invention relates to a semiconductor device having a silicon nitride film and, more particularly, to a semiconductor device having a silicon oxide film.

#2. Description of the Background Art

#The present invention will become readily understood from the following description of preferred embodiments thereof made with reference to the accompanying drawings, in which like parts are designated by like reference numeral and in which:

#FIG. 1 is a schematic view of the configuration of an apparatus depositing a silicon nitride film according to the first embodiment of the present invention;

#FIG. 2 is a graph of a relationship between a flow rate of an ammonia gas in a process of depositing a silicon nitride film and a refractive index of an obtained nitride film according to the first embodiment of the present invention;

#A process for depositing a silicon nitride film according to the embodiments of the present invention will be described with reference to the accompanying drawings as follows. In addition, an apparatus for depositing a silicon nitride film and a process of manufacturing a semiconductor device will be also described as follows.

#A process and apparatus depositing a silicon nitride film according to the first embodiment of the present invention. The configuration of an apparatus 20 depositing this silicon nitride film will be described below with reference to the schematic view in FIG. 1. This film depositing apparatus 20 includes a reaction chamber 10 depositing a silicon nitride film on a semiconductor substrate 1 by catalytic CVD reaction process. This reaction chamber 10 includes a substrate holder 2 holding the semiconductor substrate 1, a gas supply unit 4 supplying source gases 5 containing a monosilane gas (SiH4), an ammonia gas (NH3), and a hydrogen gas (H2) onto the semiconductor substrate 1 in the reaction chamber 10, and a catalyzer 6 interposed between the gas supply unit 4 and the semiconductor substrate 1. The reaction chamber 10 may include a shutter 8 shutting out flows of the source gases from the gas supply unit 4 onto the semiconductor substrate 1. In addition, this film depositing apparatus 20 includes gas tanks 11, 12, and 13 respectively storing gases such as monosilane gas, ammonia gas, and hydrogen gas which are arranged outside the reaction chamber 10. In addition, there are a gas pipe 15 connecting the gas tanks 11, 12, and 13, and the gas supply unit 4 inside of the reaction chamber 10. This film depositing apparatus 20 includes an equipment which can supply not only monosilane gas and ammonia gas but also hydrogen gas, and the hydrogen gas is additionally supplied, so that a silicon nitride film having sufficient film characteristics can be deposited even though flow rate of ammonia gas is reduced. Hereby, the flow rate of ammonia gas can be reduced. In this case, the monosilane gas (SiH4) is used as silane gas. However, the silane gas is not limited to the monosilane gas, and another silane gas (SinH2n+2) may be used.

#In addition, in the film depositing apparatus 20 depositing this silicon nitride film, a pipe line for the source gases will be described below. This film depositing apparatus 20 includes the gas tanks 11, 12, and 13 storing the monosilane gas, the ammonia gas, and the hydrogen gas. The source gases 5 containing the monosilane gas, the ammonia gas, and the hydrogen gas are guided from the gas tanks 11, 12, and 13 into the reaction chamber 10 through flow rate adjusters 14a, 14b, and 14c, the gas pipe 15, and the gas supply unit 4. In addition, an exhaust pipe 16 is arranged in the reaction chamber 10 to discharge an exhaust gas from this exhaust pipe 16. Here, the monosilane gas, the ammonia gas, and the hydrogen gas are mixed in the gas pipe 15 connected to the reaction chamber 10, however, the present invention is not limited to this configuration, and a mixing chamber (not shown) mixing these gases in advance may be arranged between the gas tanks 11, 12, and 13 and the reaction chamber 10.