JPH04279022A - Semiconductor manufacturing device - Google Patents

Abstract

PURPOSE:To form in-plane films having a uniform film thickness on a plurality of silicon substrates by uniformly dividing gas flows flowing over the silicon substrates by using baffleplates. CONSTITUTION:Sections 110 provided with multistage baffleplates are arranged between nozzles and silicon substrates 12 for uniformizing gas flows which are prepared by mixing a gaseous starting material, doping gas, and carrier gas by means of a gas mixer 16 and made to flow over the substrates 12 from the nozzles.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to semiconductor manufacturing equipment.
Specifically, the present invention relates to a semiconductor manufacturing apparatus that mixes raw material gas, doping gas, and carrier gas and blows them out from a plurality of nozzles, and simultaneously deposits semiconductor crystals on a plurality of silicon substrates corresponding to each nozzle.

0002

2. Description of the Related Art Improving the throughput of semiconductor film forming processes is an industrially important issue. In response to such demands, semiconductor crystals are being deposited simultaneously on a plurality of substrates within one apparatus. A typical growth furnace is called a vertical furnace, in which multiple substrates are arranged in layers at certain intervals. A nozzle is installed for each substrate, and the mixed raw material gas, doping gas, and carrier gas are blown out parallel to the substrate from each nozzle toward each substrate, and the above gases are transported to the substrate. The film is being deposited. For example, in silicon epitaxial growth, dichlorosilane is used as a source gas and hydrogen is used as a carrier gas, and the above gas is sprayed onto about 30 silicon substrates from a nozzle corresponding to each substrate. A heating device is installed outside the reaction tube, the substrate is set at a predetermined temperature, and silicon crystals are deposited on the substrate using the gas-based chemical reaction. The film is deposited under a predetermined pressure inside the reaction tube by reducing the pressure to normal pressure or by using a rotary pump or the like.

0003

Problems to be Solved by the Invention When growth is performed by blowing source gas and carrier gas toward a substrate from a nozzle, the gas flowing over the substrate becomes non-uniform. That is, since the flow of gas blown out from the nozzle is beam-shaped, parts with a high concentration of source gas and parts with a low concentration of raw material gas appear on the substrate. Due to such concentration unevenness, the thickness of the deposited film becomes non-uniform within the plane. SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor manufacturing apparatus that eliminates such conventional drawbacks and makes it possible to deposit films of uniform thickness on a plurality of substrates.

0004

[Means for Solving the Problems] The present invention has a baffle plate that makes the flow of gas uniform between each nozzle and each substrate, makes the flow of gas flowing on each substrate uniform, and as a result, This is a semiconductor manufacturing apparatus that deposits a semiconductor film having a uniform thickness in the plane of the substrates on a plurality of substrates.

[0005]

[Operation] The reason why the film thickness differs within the plane of the substrate is that the flow of the raw material gas and carrier gas blown out from the nozzle is non-uniform within the plane. For example, when several liters/min of gas is released from a nozzle with a diameter of 1 mm under conditions of 1/100 atmospheric pressure, the flow rate of the gas blown out from the nozzle can easily reach several hundred m/sec. It becomes speed. For this reason, the gas flow becomes highly directional in a particular direction. That is, the gas flow becomes beam-shaped, and the raw material gas concentration is high at the center of the gas flow, but the gas concentration rapidly becomes thinner as it moves away from there.

[0006] When a flow having such a spatial distribution of source gas flows over a substrate, non-uniformity occurs in the thickness of the deposited film corresponding to non-uniformity in the concentration of the source gas. Such non-uniformity is particularly noticeable when the flow rate of the gas discharged from the nozzle is high. On the other hand, by providing a structure that disturbs the flow of gas between the nozzle and the substrate, it is possible to realize uniformity of the gas flowing over the substrate. For example, uniformity can be achieved by blowing the gas emitted from a nozzle once against a quartz wall to disturb the beam-shaped gas flow.

[0007]

Embodiments Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of a semiconductor manufacturing apparatus of the present invention. FIG. 2 is a schematic diagram showing an example of a gas homogenization structure used in Example 1 of the present invention, in which FIG. 2A is a top view and FIG. 2B is a side view. The apparatus of Example 1 includes a reaction tube 11 for performing growth, a silicon substrate 12, and a susceptor 13 for holding the silicon substrate 12.
, a heating device 14 for heating the silicon substrate 12 and the susceptor 13, cylinders 15a and 15b, a gas mixer 16, a flow rate control section 17, a hydrogen gas purification device 18, a gas introduction pipe 19, and a part that makes the flow of gas uniform. 110, and a rotary pump 111 for reducing the pressure inside the reaction tube.

Dichlorosilane gas was used as the raw material gas, and hydrogen gas was used as the carrier gas. Hydrogen gas was purified by a high-purity purifier 18 and used. The flow rate of dichlorosilane gas was 200 cc/min, and the flow rate of hydrogen gas was 30 liters/min. The number of substrates was 30. Figure 2 shows a structure for making the gas flow uniform. Gas discharged from the nozzle 21 is blown onto one baffle plate 22 made of high-purity synthetic quartz and is divided into two streams. The flow thus divided is again divided by two baffle plates 23 made of high-purity synthetic quartz. It has a structure in which it is further divided by three quartz baffle plates 24 and then flows onto a substrate 25. As a pretreatment of the substrate, first RCA cleaning was performed and the substrate was set in a reaction tube. Thereafter, the natural oxide film on the surface of the substrate was removed by baking at 1000° C. for 5 minutes in a hydrogen atmosphere. After that, the growth temperature was set to 95% as the gas flow rate condition.
Growth was performed under the conditions of 0° C., growth pressure of 50 Torr, and growth time of 30 minutes. The substrate is a 6-inch silicon
100> was used.

As a result, by making the gas flow uniform over the substrate, the in-plane film thickness variation was reduced to 5%, compared to the 10% in-plane variation that would occur without a conventional gas uniformity structure. We were able to keep it within %. This time, epitaxial growth of silicon was performed using the apparatus of this embodiment, but similar effects can be obtained in polycrystalline growth of silicon. Furthermore, similar effects can be obtained in the growth of materials other than silicon. Furthermore, this time, the baffle plates made of quartz that divide the gas were set in three stages, but the number of stages can be changed depending on the growth conditions and the degree of uniformity required.

Next, a second embodiment of the present invention will be explained in detail with reference to the drawings. FIG. 3 is a perspective view showing an example of a baffle plate for gas uniformity used in Example 2 of the present invention. FIG. 4 is a schematic diagram showing a structure for gas uniformity used in Example 2 of the present invention, in which FIG. 4A is a top view and FIG. 4B is a side view. The basic configuration of the device used in this example was the same as in Example 1. As shown in FIG. 3, the baffle plate used to make the gas flow uniform was a synthetic quartz plate with a plurality of holes. The gas discharged from the nozzle 41 is blown onto a baffle plate 42 made of high-purity synthetic quartz having two holes each having a diameter of 8 mm, and is divided into two streams. The flow thus divided is again divided by a baffle plate 43 made of high-purity synthetic quartz and having five holes. It is further divided by a quartz baffle plate 44 having seven holes, and then flows onto a substrate 45.

[0011] As a pretreatment of the substrate, first RCA cleaning was performed and the substrate was set in a reaction tube. After that, Example 1
Growth was carried out under similar conditions. As a result, by making the gas flow uniform over the substrate, the in-plane film thickness variation was reduced to within 5%, compared to the 10% in-plane variation that would occur without a conventional gas uniformity structure. I was able to suppress it. Furthermore, in this case, three baffle plates made of quartz were used to divide the gas, but the number can be changed depending on the growth conditions and the degree of uniformity required. Further, the number of holes drilled in each plate, as well as the size and shape of the holes are selected as appropriate.

0012

Effects of the Invention As described above in detail, by using the apparatus according to the present invention, the flow of gas flowing over each substrate can be made uniform, and as a result, a uniform in-plane film thickness can be obtained on a plurality of substrates. It becomes possible to deposit a film.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a semiconductor device of the present invention.

FIG. 2 is a schematic diagram showing an example of a gas homogenization structure used in Example 1 of the present invention, in which FIG. 2A is a top view and FIG. 2B is a side view.

FIG. 3 is a perspective view showing an example of a baffle plate for gas uniformity used in Example 2 of the present invention.

FIG. 4 is a schematic diagram showing an example of a gas homogenization structure used in Example 2 of the present invention, in which FIG. 4A is a top view and FIG. 4B is a side view.

[Explanation of symbols]

11 Reaction tube 12 Silicon substrate 13 Susceptor 14 Heating device 15a, 15b Cylinder 16 Gas mixer 17 Flow rate control section 18 Purification device 19 Gas introduction tube 110 Part 111 that makes gas flow uniform
Rotary pump 21 Nozzles 22, 23, 24 Baffle plate 25 Substrate 41 Nozzles 42, 43, 44 Baffle plate 45 Substrate

Claims (1)

[Claims] 1. A semiconductor manufacturing apparatus that simultaneously deposits semiconductor crystals on a plurality of substrates corresponding to each nozzle by mixing a raw material gas, a doping gas, and a carrier gas and blowing the mixture out of a plurality of nozzles. A semiconductor manufacturing device comprising a baffle plate between a nozzle and a substrate for making gas flowing over the substrate uniform within the plane of the substrate.