Epitaxial Growth Equipment

Abstract

To provide an epitaxial growth device that quickly replaces purge gas in an additional dopant gas sub-supply pipe that introduces additional dopant gas for resistivity adjustment, and supplies the additional dopant gas into a reactor.SOLUTION: A single-wafer epitaxial growth device that performs epitaxial growth by supplying raw material gas to a substrate placed on a substrate mounting table in a deposition chamber includes a film-forming gas supply pipe that supplies film-forming gas, a dopant gas supply pipe that supplies dopant gas, a raw material gas main supply pipe formed by merging with a carrier gas main supply pipe that supplies carrier gas, a plurality of raw material gas sub-supply pipes formed by branching from the raw material gas main supply pipe, and an additional dopant gas sub-supply pipe connected to the plurality of raw material gas sub-supply pipes, and to the additional dopant gas sub-supply pipe, a carrier gas sub-supply pipe branched from the carrier gas main supply pipe is connected.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an epitaxial growth apparatus. [Background technology]

[0002] Due to miniaturization and high integration of semiconductor devices, the quality requirements for the thickness and resistivity of the epitaxial silicon film of the epitaxial silicon single crystal substrate epitaxially grown on the silicon single crystal substrate are becoming increasingly strict. A conventional epitaxial growth apparatus is shown in FIG. 5. The conventional epitaxial growth apparatus includes a film formation gas supply pipe 1 capable of adjusting the flow rate for supplying a film formation gas, a dopant gas supply pipe 2 capable of adjusting the flow rate for supplying a dopant gas, and a carrier gas main supply pipe 3 capable of adjusting the flow rate for supplying a carrier gas, which are joined together to provide the raw material gas. The conventional epitaxial growth apparatus also includes a plurality of raw material gas sub-supply pipes 5 branched from the raw material gas main supply pipe 4, which supply the raw material gas in one direction parallel to the substrate mounting surface of the substrate mounting table 20 in the film formation chamber 30, and at least one additional dopant gas sub-supply pipe 6 capable of adjusting the flow rate, which is connected to at least one of the plurality of raw material gas sub-supply pipes 5. The additional dopant gas sub-supply pipe 6 and the source gas sub-supply pipe 5 join at a junction 10. The additional dopant gas sub-supply pipe 6 is a branch of the additional dopant gas auxiliary supply pipe 8. In order to adjust the resistivity distribution of the epitaxially grown film, additional dopant gas (AUX-DOPE, Auxiliary Dope) for adjusting resistivity has been locally introduced from the additional dopant gas sub-supply pipes 6 (e.g., six pipes) to the multiple source gas (trichlorosilane, dopant gas, H2 carrier gas) sub-supply pipes 5 (e.g., eight pipes).

[0003] Furthermore, the following techniques are known for adjusting the resistivity distribution of an epitaxial growth apparatus. Patent Document 1 describes an epitaxial apparatus that takes into account the effects of autodoping when performing epitaxial growth on a low-resistivity substrate, and supplies dopant gas from multiple gas inlets near the center of the diameter of the substrate to make the in-plane distribution of resistivity uniform. Patent Document 2 describes an epitaxial apparatus that, when performing epitaxial growth on a low-resistivity substrate, takes into consideration the effects of autodoping and supplies dopant gas from three central gas inlets out of five gas inlets near the center of the diameter of the substrate, while not supplying dopant gas from the gas inlets on either side, thereby making the in-plane distribution of resistivity uniform. Patent Document 3 describes an apparatus and method for supplying a doping gas together with a dilution gas into a furnace in an epitaxial apparatus. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2000 / 026949 [Patent Document 2] JP 2001-044125 A [Patent Document 3] JP 2004-179499 A Summary of the Invention [Problem to be solved by the invention]

[0005] When epitaxial growth is performed on a silicon single crystal substrate using the conventional epitaxial growth apparatus shown in Figure 5, the flow rate of the additional dopant gas is extremely small relative to the source gas, so even if the gas supply pipes are switched at the same time, the supply timing will be shifted. When the resistivity profile of these epitaxially grown films is examined, a phenomenon occurs in which an abnormality in resistivity occurs in the depth direction of the epitaxially grown film at the start of epitaxial growth, that is, due to a decrease in the amount of dopant gas in the epitaxially grown film on the silicon single crystal substrate side.

[0006] As a result of the inventor's thorough investigation of this phenomenon, it was surmised that the cause was that there was accumulation at the junction between the switching valve of the additional dopant gas (AUX-DOPE) piping that adjusts resistivity and the main piping that supplies the raw material gas, and that the flow rate of the additional dopant gas (AUX-DOPE) was very small compared to the raw material gas, and furthermore, because it branches into six, it became even smaller, and therefore it took time to replace the accumulation in the additional dopant gas piping with purge gas (H2).

[0007] The present invention has been made to solve the above problems, and has an object to provide an epitaxial growth apparatus that can quickly replace the purge gas in an additional dopant gas sub-supply pipe that introduces additional dopant gas for adjusting resistivity, and supply the additional dopant gas into a reactor, thereby preventing abnormalities in resistivity in the depth direction of an epitaxially grown film. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a single-wafer epitaxial growth apparatus for supplying a source gas to a substrate placed on a substrate placement table in a film formation chamber to perform epitaxial growth, the apparatus comprising: a main source gas supply pipe for supplying the source gas, the main source gas supply pipe being formed by joining together at least a film forming gas supply pipe capable of adjusting the flow rate thereof for supplying a film forming gas, a dopant gas supply pipe capable of adjusting the flow rate thereof for supplying a dopant gas, and a main carrier gas supply pipe capable of adjusting the flow rate thereof for supplying a carrier gas; a plurality of source gas sub-supply pipes formed by branching the source gas main supply pipe, the plurality of source gas sub-supply pipes supplying the source gas in one direction parallel to the substrate mounting surface of the substrate mounting table; at least one additional dopant gas sub-supply pipe capable of adjusting a flow rate is provided, the additional dopant gas sub-supply pipe being connected to at least one of the plurality of source gas sub-supply pipes; The at least one additional dopant gas sub-supply pipe is connected to a carrier gas sub-supply pipe that is branched off from the carrier gas main supply pipe and has an adjustable flow rate.

[0009] With such an epitaxial growth apparatus, it is possible to quickly replace the purge gas in the additional dopant gas sub-supply pipe that introduces the additional dopant gas for adjusting resistivity, and to supply the additional dopant gas into the reaction furnace, thereby making it possible to prevent abnormalities in the resistivity of the epitaxial growth film in the depth direction.

[0010] In the present invention, it is preferable that the additional dopant gas auxiliary supply pipes are provided in a plurality of pieces, and the plurality of additional dopant gas auxiliary supply pipes are formed by branching one additional dopant gas main supply pipe formed by joining the carrier gas auxiliary supply pipe and the additional dopant gas auxiliary supply pipe.

[0011] With such an epitaxial growth apparatus, the additional dopant gas can be more efficiently supplied into the reaction furnace, and as a result, abnormalities in resistivity in the depth direction of the epitaxially grown film can be prevented.

[0012] In the present invention, it is preferable that the gas supply system includes four or more source gas sub-supply pipes, and each of the four or more source gas sub-supply pipes is connected to the additional dopant gas sub-supply pipe.

[0013] Such an epitaxial growth apparatus can improve the uniformity of the resistivity distribution within the surface of the epitaxial growth substrate, while preventing abnormalities in resistivity in the depth direction of the epitaxially grown film. Effect of the Invention

[0014] As described above, the epitaxial growth apparatus of the present invention can eliminate the influence of accumulation of the additional dopant gas (AUX-DOPE) at the junction of the additional dopant gas sub-supply pipe and the source gas sub-supply pipe, and minimize the time required for replacing the purge gas accumulation in the pipe (purge time), thereby eliminating discrepancies in the timing of supplying the additional dopant gas (AUX-DOPE) into the reactor and preventing abnormalities in the resistivity profile in the depth direction of the epitaxial growth film. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing an example of an epitaxial growth apparatus of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of an additional dopant gas sub-supply pipe used in the present invention. [Diagram 3] 13 is a graph showing the relationship between resistivity in the depth direction and film thickness in a comparative example. [Figure 4] 1 is a graph showing the relationship between resistivity in the depth direction and film thickness in an example and a comparative example. [Diagram 5] FIG. 1 is a schematic diagram showing an example of a conventional epitaxial growth apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] As described above, there was a need to develop an epitaxial growth apparatus that can quickly replace the purge gas in the additional dopant gas sub-supply pipe (AUX-DOPE) that introduces additional dopant gas for adjusting resistivity, and supply the additional dopant gas into the reactor.

[0017] The reason for the timing shift in supplying the dopant gas (AUX-DOPE) for adjusting resistivity is that it takes time to replace the purge gas in the additional dopant gas pipe as described above. Therefore, the inventors discovered that by branching the carrier gas (or purge gas) pipe, connecting it to the additional dopant gas (AUX-DOPE) pipe, and flowing the carrier gas together with the additional dopant gas to increase the flow rate of the total gas flowing through the pipe, the purge gas in the additional dopant gas supply pipe that introduces the additional dopant gas for adjusting resistivity can be quickly replaced, and an epitaxial growth apparatus that supplies the additional dopant gas into the reactor can be achieved, and the present invention has been completed.

[0018] That is, the present invention is a single-wafer epitaxial growth apparatus for supplying a source gas to a substrate placed on a substrate placement table in a film formation chamber to perform epitaxial growth, a main source gas supply pipe for supplying the source gas, the main source gas supply pipe being formed by joining together at least a film forming gas supply pipe capable of adjusting the flow rate thereof for supplying a film forming gas, a dopant gas supply pipe capable of adjusting the flow rate thereof for supplying a dopant gas, and a main carrier gas supply pipe capable of adjusting the flow rate thereof for supplying a carrier gas; a plurality of source gas sub-supply pipes formed by branching the source gas main supply pipe, the plurality of source gas sub-supply pipes supplying the source gas in one direction parallel to the substrate mounting surface of the substrate mounting table; at least one additional dopant gas sub-supply pipe capable of adjusting a flow rate is provided, the additional dopant gas sub-supply pipe being connected to at least one of the plurality of source gas sub-supply pipes; In the epitaxial growth apparatus, the at least one additional dopant gas sub-supply pipe is connected to a carrier gas sub-supply pipe that is branched off from the carrier gas main supply pipe and has an adjustable flow rate.

[0019] The present invention will be described in detail below with reference to the drawings, but the present invention is not limited thereto.

[0020] [Epitaxial growth equipment] The epitaxial growth apparatus of the present invention will be described with reference to Fig. 1. The present invention is a single-wafer epitaxial growth apparatus 100 that supplies source gas to a substrate placed on a substrate mounting table 20 in a film formation chamber 30 to perform epitaxial growth. The system is equipped with at least a film formation gas supply pipe 1 capable of adjusting the flow rate for supplying a film formation gas, a dopant gas supply pipe 2 capable of adjusting the flow rate for supplying a dopant gas, and a main carrier gas supply pipe 3 capable of adjusting the flow rate for supplying a carrier gas, which are joined together to supply a raw material gas. In addition, the source gas main supply pipe 4 is branched into a plurality of source gas sub-supply pipes 5, which supply the source gas in one direction parallel to the substrate mounting surface of the substrate mounting table 20; At least one additional dopant gas sub-supply pipe 6 capable of adjusting a flow rate is provided, which is connected to at least one of the plurality of source gas sub-supply pipes 5; In the epitaxial growth apparatus, at least one additional dopant gas sub-supply pipe 6 is connected to a carrier gas sub-supply pipe 7 that is branched off from the carrier gas main supply pipe 3 and has an adjustable flow rate.

[0021] With such an epitaxial growth apparatus, it is possible to quickly replace the purge gas in the additional dopant gas sub-supply pipe (AUX-DOPE) that introduces additional dopant gas for adjusting resistivity, and to supply the additional dopant gas into the reaction furnace, thereby making it possible to prevent abnormalities in the resistivity of the epitaxial growth film in the depth direction.

[0022] [Gas supply piping for deposition] The film forming gas supply pipe 1 according to the present invention is a pipe capable of adjusting the flow rate of the film forming gas that is supplied. The film forming gas is not particularly limited, but may be, for example, a silane-based gas such as trichlorosilane.

[0023] [Dopant gas supply piping] The dopant gas supply pipe 2 according to the present invention is a pipe capable of adjusting the flow rate of the dopant gas that is supplied. The dopant gas is not particularly limited, but for example, a boron-based gas such as diborane can be used for p-type, a phosphorus-based gas such as phosphine can be used for n-type, or an arsenic-based gas such as arsine can be used for n-type.

[0024] [Carrier gas main supply piping] The carrier gas main supply pipe 3 according to the present invention is a pipe capable of adjusting the flow rate of the carrier gas that is supplied. The carrier gas is not particularly limited, but may be, for example, hydrogen (H2) gas.

[0025] [Main raw gas supply pipe] The main source gas supply pipe 4 according to the present invention is a pipe where the film forming gas supply pipe 1, the dopant gas supply pipe 2, and the main carrier gas supply pipe 3 join together. The source gas supplied by the main source gas supply pipe 4 is a mixture of the above-mentioned film forming gas, dopant gas, and carrier gas.

[0026] [Raw gas sub-supply piping] The source gas sub-supply pipes 5 according to the present invention are a plurality of pipes branched from the source gas main supply pipe 4. The source gas sub-supply pipes 5 supply the source gas in one direction parallel to the substrate mounting surface of the substrate mounting table 20. The number of source gas sub-supply pipes 5 is not particularly limited, but it is preferable that four or more pipes are provided.

[0027] 1, the source gas sub-supply pipe 5 is illustrated as being provided on the wall surface of the film formation chamber 30, but the installation form of the source gas sub-supply pipe 5 is not limited to this. It may have a structure connected to the film formation chamber 30 so as to ultimately supply the source gas in one direction parallel to the substrate mounting surface of the substrate mounting table 20.

[0028] [Additional dopant gas sub-supply piping] The additional dopant gas sub-supply pipe 6 according to the present invention is at least one pipe capable of adjusting the flow rate, which is connected to at least one of the multiple source gas sub-supply pipes 5. The number of additional dopant gas sub-supply pipes 6 is not particularly limited, but when four or more source gas sub-supply pipes 5 are provided, it is preferable that four or more are provided. In this case, it is preferable that one additional dopant gas sub-supply pipe 6 is connected to each of the four or more source gas sub-supply pipes 5, and a total of four or more additional dopant gas sub-supply pipes 6 are connected. A source gas sub-supply pipe 5 to which no additional dopant gas sub-supply pipe 6 is connected may be provided. For example, eight source gas sub-supply pipes 5 may be provided, and one additional dopant gas sub-supply pipe 6 may be connected to each of six of them. Alternatively, one additional dopant gas sub-supply pipe 6 may be connected to each of all source gas sub-supply pipes 5. In such a case, by adjusting the flow rate of the additional dopant gas sub-supply pipes 6 and setting the flow rate of the additional dopant gas supplied from some of the additional dopant gas sub-supply pipes 6 to 0, it is possible to have the same performance as that of, for example, the above-mentioned eight source gas sub-supply pipes 5, six of which are connected to each of the additional dopant gas sub-supply pipes 6. Such an epitaxial growth apparatus 100 is preferable because it can more efficiently prevent abnormalities in resistivity in the depth direction of the epitaxial growth film. The additional dopant gas sub-supply pipe 6 and the source gas sub-supply pipe 5 join at a joining portion 10 .

[0029] 1, the source gas sub-supply pipe 5 and the additional dopant gas sub-supply pipe 6 are represented by solid and dotted lines, but this indicates that there are a plurality of source gas sub-supply pipes 5 and one or more additional dopant gas sub-supply pipes 6, and does not indicate that there are pipes other than the source gas sub-supply pipe 5 and the additional dopant gas sub-supply pipe 6 by the solid and dotted lines. Also, FIG. 1 is a schematic diagram showing an example of the epitaxial growth apparatus of the present invention, and the number of source gas sub-supply pipes 5 and additional dopant gas sub-supply pipes 6 is not limited to the number shown in FIG.

[0030] When a plurality of additional dopant gas sub-supply pipes 6 are provided, it is preferable that the plurality of additional dopant gas sub-supply pipes 6 are formed by branching one additional dopant gas main supply pipe 9 formed by joining a carrier gas sub-supply pipe 7 and an additional dopant gas auxiliary supply pipe 8 described later.

[0031] The dopant gas contained in the additional dopant gas supplied from the additional dopant gas sub-supply pipe 6 is usually the same as the dopant gas supplied from the dopant gas supply pipe 2, but may be different.

[0032] [Carrier gas secondary supply piping] The carrier gas sub-supply pipe 7 according to the present invention is a flow rate adjustable pipe branched off from the carrier gas main supply pipe 3. The carrier gas sub-supply pipe 7 is connected to at least one additional dopant gas sub-supply pipe 6.

[0033] FIG. 2 shows an example of the additional dopant gas sub-supply pipe 6 used in the present invention. The method of forming a film using the epitaxial growth apparatus of the present invention described above is basically the same as the conventional method, but when the epitaxial growth apparatus of the present invention is used, carrier gas is supplied from the carrier gas sub-supply pipe 7 when dopant is supplied from the additional dopant gas sub-supply pipe 6 during film formation. By using such an additional dopant gas sub-supply pipe, the present invention can efficiently supply additional dopant gas into the reaction furnace. EXAMPLES

[0034] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to these.

[0035] (Example) Epitaxial growth was performed on a silicon single crystal substrate using the epitaxial growth apparatus of the present invention equipped with the carrier gas sub-supply pipe 7 shown in Fig. 1. At this time, when 2 slm of carrier gas was added from the carrier gas sub-supply pipe 7 to the additional dopant gas sub-supply pipe 6 (AUX-DOPE), the purge time required to replace the purge gas reservoir in the additional dopant gas sub-supply pipe 6 was estimated to be about 0.2 sec.

[0036] (Comparative Example) Epitaxial growth was performed on a silicon single crystal substrate using a conventional epitaxial growth apparatus not equipped with the carrier gas sub-supply pipe 7 shown in Fig. 5. The time required for the source gas to reach the junction 10 of the additional dopant gas sub-supply pipe 6 (AUX-DOPE) and the source gas sub-supply pipe 5 was estimated to be about 0.2 sec. The purge time required for the purge gas reservoir in the additional dopant gas sub-supply pipe 6 to be replaced was estimated to be about 2.2 sec. FIG. 3 is a graph showing the relationship between resistivity in the depth direction and film thickness obtained in the comparative example. FIG. 4 shows a graph illustrating the relationship between resistivity in the depth direction and film thickness obtained in the example and the comparative example.

[0037] As shown in Fig. 3, in the comparative example, an abnormality in resistivity was observed at 1 to 2 µm, which corresponds to the initial stage of film formation in the depth direction. On the other hand, as shown in Fig. 4, which shows both the example and the comparative example, in the example using the epitaxial growth apparatus of the present invention, no abnormality in resistivity was observed in the depth direction.

[0038] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention. [Explanation of symbols]

[0039] 1...film formation gas supply pipe; 2...dopant gas supply pipe; 3...Main carrier gas supply pipe; 4...Main raw material gas supply pipe; 5...source gas sub-supply pipe; 6...additional dopant gas sub-supply pipe; 7... carrier gas auxiliary supply pipe; 8... additional dopant gas auxiliary supply pipe; 9: additional dopant gas main supply pipe; 10: junction; 20: substrate placement table; 30...film formation chamber, 100...epitaxial growth apparatus.

Claims

1. A single-wafer epitaxial growth apparatus for supplying a source gas to a substrate placed on a substrate placement table in a film formation chamber to perform epitaxial growth, comprising: a main source gas supply pipe for supplying the source gas, the main source gas supply pipe being formed by joining together at least a film forming gas supply pipe capable of adjusting the flow rate thereof for supplying a film forming gas, a dopant gas supply pipe capable of adjusting the flow rate thereof for supplying a dopant gas, and a main carrier gas supply pipe capable of adjusting the flow rate thereof for supplying a carrier gas; a plurality of source gas sub-supply pipes formed by branching the source gas main supply pipe, the plurality of source gas sub-supply pipes supplying the source gas in one direction parallel to the substrate mounting surface of the substrate mounting table; at least one additional dopant gas sub-supply pipe capable of adjusting a flow rate is provided, the additional dopant gas sub-supply pipe being connected to at least one of the plurality of source gas sub-supply pipes; an epitaxial growth apparatus comprising: a carrier gas sub-supply pipe having a flow rate adjustable branched from the carrier gas main supply pipe, the at least one additional dopant gas sub-supply pipe being connected to the carrier gas main supply pipe;

2. 2. The epitaxial growth apparatus according to claim 1, further comprising a plurality of the additional dopant gas sub-supply pipes, the plurality of additional dopant gas sub-supply pipes being formed by branching a single additional dopant gas main supply pipe formed by joining the carrier gas sub-supply pipe and the additional dopant gas auxiliary supply pipe.

3. 3. The epitaxial growth apparatus according to claim 1, further comprising four or more source gas sub-supply pipes, each of which is connected to the additional dopant gas sub-supply pipe.

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