JPH0739228Y2 - Light heat treatment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an optical heating apparatus for a semiconductor wafer in a semiconductor device manufacturing process.

[Outline of device]

The present invention relates to a semiconductor wafer optical heating apparatus used in a semiconductor device manufacturing process. More specifically, the semiconductor wafer in a transparent quartz tube is heated by a light heating lamp through a susceptor having a high radiation light absorption efficiency. However, the present invention relates to an optical heat treatment apparatus for measuring and controlling the temperature of this semiconductor wafer with a radiation thermometer.

[Conventional technology]

In a semiconductor device manufacturing process, high-temperature heat treatment at around 1000 ° C. is performed such as formation of a thermal oxide film of a semiconductor wafer made of a compound such as Si or GaAs or activation of an ion implantation layer. Conventionally, for this purpose, it has been usual to carry out the heating for several minutes to several tens of minutes using an electric furnace heat treatment apparatus by resistance heating. This method requires a large amount of electric power in the electric furnace, and the processing time is long, so that the manufacturing efficiency is poor, and it is not suitable when a heat treatment for a short time such as preventing re-diffusion of impurities is required.

Therefore, in recent years, RTA (Rapid Thermium) that performs light heating processing in a short time of several seconds to several tens of seconds by radiating radiant light from a light heating lamp.
al Annealing) method or RTP (Rapid Thermal Proces)
s) The method is being put to practical use. FIG. 2 is a diagram showing an example of a conventional light heat treatment apparatus. This will be described with reference to FIG. 1. The semiconductor wafer 1 in the transparent quartz tube 4 is placed on the susceptor 2 made of a material such as carbon or silicon,
Light heating is performed from above and below by a light heating lamp 6 such as a quartz halogen lamp. The temperature of the semiconductor wafer 1 is the susceptor 2
A thermocouple 8 bonded to the above with a heat-resistant adhesive 9 indirectly detects it as a thermoelectromotive force (for example, JP-A-61-14273).
No. 7).

Further, as another example of the conventional light heat treatment apparatus, as shown in FIG. 3, very recently, a method of measuring and controlling the temperature of a semiconductor wafer by a radiation thermometer has been used. This will be described with reference to FIG. The semiconductor wafer 1 in the transparent quartz tube 4 is usually placed alone on the holding jig 3 in order to reduce the heat capacity and improve the thermal response. The temperature of the semiconductor wafer 1 which has been subjected to the light heating treatment by the light heating lamp 6 is passed through the observation window 11 which is airtightly adhered to the end portion of the branch tube 10 welded to the transparent quartz tube 4 with the heat resistant adhesive 12 or the like. It is configured to be measured and controlled by the radiation thermometer 5. (For example RESheets, Mat.Res.Soc.Symp.Proc.,
52 , 191 (1986)).

As this modification, a conventional example in which the semiconductor wafer 4 is placed on a susceptor made of quartz is also known (for example, JP-A-61-130).
No. 834).

[Problems to be solved by the device]

Among the above-described conventional light heat treatment apparatuses, the method of measuring and controlling the temperature of the semiconductor wafer by using the thermocouple shown in FIG. 2 has a detection end of the thermocouple 8 which is not in direct contact with the semiconductor wafer. Accurate temperature measurement is difficult, and since the metal thermocouple 8 and the heat-resistant adhesive 9 are present in the transparent quartz tube 4, there is a problem that the semiconductor wafer 1 is contaminated.

Further, another conventional method of measuring and controlling the temperature of the semiconductor wafer 1 using the radiation thermometer 5 through the branch pipe 10 and the viewing window 11 shown in FIG. 3 is to measure the detection element of the radiation thermometer 5. For example, it is necessary to use a PE (Pyroelectric) element having a wavelength of 4.5 μm or more and a special material such as calcium fluoride (CaF ₂₎ having a transmission wavelength range of 4.5 μm or more for the viewing window 11. Is based on the interrelationship of the detection element of the radiation thermometer, the light source of the optical heating lamp and the wavelength range of the transmission wavelength of each material shown in Fig. 4. That is, the heated S
If the radiation light from the semiconductor wafer 1 such as i or GaAs is measured and controlled by the radiation thermometer directly through the wall of the transparent quartz tube 4, the detection element is 4.5 μm or less, which is within the transparent wavelength range of quartz. Si, Ge, Pbs or PbSe with measurement sensitivity
Must be used. However, the radiant light in the measurement wavelength range of these detection elements is Si, Ga
Since it passes through the semiconductor wafer 1 such as As, the radiant light of the light heating lamp 6 facing the radiation thermometer 5 is also detected,
It was impossible to accurately measure and control the temperature of the semiconductor wafer 1. Therefore, the transmission wavelength range of quartz (0.155 to 4.5 μm)
CaF _{2 that} transmits to longer wavelengths (transmission wavelength range 0.13 to 12
A viewing window 11 made of a material such as μm) is provided at the end of the branch pipe 10 welded to the quartz tube 4, and the measurement wavelength range is provided on the longer wavelength side than the transmission wavelength range of quartz through this viewing window 11. It was necessary to use the radiation thermometer 5 having a PE detection element (measurement wavelength range 8 to 13 μm) and the like.

An apparatus having such a complicated structure is expensive, and it is necessary to pay close attention to maintenance such as cleaning the inside. Furthermore, when heating with the light heating lamp 6, a branch pipe 10 and a viewing window
Although the 11th part is not heated directly, it is a part that may reach high temperature, and the reliability of the heat-resistant adhesive 12 that hermetically bonds two types of materials with different thermal expansion coefficients is a problem. It was Especially, toxic gas is generated by heat treatment such as GaAs,
When introducing a toxic gas such as arsine (AsH ₃ ) for heat treatment, this device could not be used in terms of reliability.

Therefore, an object of the present invention is to measure and control the temperature of the semiconductor wafer accurately and with good thermal response when the semiconductor wafer in the transparent quartz tube is subjected to light heating treatment. SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical heat treatment apparatus which is free from the concern of, and is easy to maintain, such as cleaning the apparatus, and has no risk of leakage of toxic gas even when toxic gas is used.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the light heat treatment apparatus according to the present invention is configured as follows.

The semiconductor wafer is mounted on a susceptor made of a material that efficiently absorbs the radiant light of the light heating lamp, and this susceptor is further mounted on a transparent quartz holding jig and placed in a transparent quartz tube. The semiconductor wafer is indirectly heated through the susceptor by a light heating lamp located outside the transparent quartz tube and arranged below the susceptor. The temperature of the semiconductor wafer is measured and controlled directly through the wall of the transparent quartz tube by a radiation thermometer located outside the transparent quartz tube and arranged at a position where the semiconductor wafer is viewed from above.

In the device configured as described above, the material of the susceptor efficiently absorbs the radiant light of the light heating lamp, such as carbon or silicon carbide, is stable even at a high temperature of about 1300 ° C, and does not cause contamination to the semiconductor wafer. High-purity ones are used.

The shape of the susceptor is excellent in flatness on the semiconductor wafer mounting surface side, and the thickness is preferably 1 mm or more and 5 mm or less, and 2 mm or more and 3 mm or less.
The following is more desirable. The planar shape may be any as long as it is wider than the semiconductor wafer to be mounted and has a projected area where the radiant light of the light heating lamp does not directly enter the radiation thermometer.

As a radiation thermometer, the transmission wavelength range of quartz (0.155 to 4.5
The one having a detection element such as ordinary Si, Ge, PbS, or PbSe having a sensitivity of (μm) is used.

[Action]

Radiant light from the light heating lamp is absorbed by the susceptor to heat it, and the semiconductor wafer is indirectly heated mainly by heat conduction from the flat semiconductor wafer mounting surface of the susceptor. The temperature of the semiconductor wafer is measured and controlled by a radiation thermometer directly through the wall of the transparent quartz tube. The radiant light of the light heating lamp is efficiently absorbed by the susceptor having a larger area than that of the semiconductor wafer, so that the temperature of the semiconductor wafer can be accurately measured without directly entering the radiation thermometer. Since the thickness of the susceptor is 1 mm or more and 5 mm or less, it is not too thin and mechanically fragile, and the temperature distribution characteristic is not bad, and conversely, it is not too thick and the heat response characteristic is not bad.

Furthermore, the light heating processing device according to the present invention is provided with
Since there is no adhesive part, there is no concern about leakage of toxic gas, it is highly reliable, and maintenance such as cleaning is easy.

Further, since there is no thermocouple or heat-resistant adhesive in the transparent quartz tube, there is no concern that the semiconductor wafer will be contaminated with impurities.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG. 1 is a view showing a light heating device according to the present invention. In this embodiment, a GaAs compound that has been subjected to an ion implantation process is used as an example of the semiconductor wafer 1, and the apparatus will be described for the case where this ion implantation layer is activated.

A susceptor 2 having a flat mounting surface and having a larger area than the semiconductor wafer and made of carbon and having a thickness of 2 mm is placed on a holding jig 3 made of transparent quartz, and the semiconductor wafer 1 is placed on the susceptor 2. And insert it into the transparent quartz tube 4. Although not shown in FIG. 1, a gas introduction hole and a gas discharge hole are connected to both ends of the transparent quartz tube 4, and arsine (AsH ₃ ) is introduced from this gas introduction hole to the gas discharge hole. It is led to an exhaust gas treatment device outside the transparent quartz tube 4. A light heating lamp 6 made of a quartz halogen lamp and a reflecting plate 7 are arranged below the susceptor 2 and outside the transparent quartz tube, and the susceptor 2 is optically heated from the lower surface, whereby a semiconductor mounted closely on the susceptor 2 is mounted. The wafer 1 is indirectly heated. The temperature of the semiconductor wafer 1 is measured using a radiation thermometer 5 having a Si detection element which is located outside the transparent quartz tube 4 and is located on the susceptor 2 at a position overlooking the semiconductor wafer 1. Although not shown in FIG. 1, the temperature information output of the radiation thermometer 5 is input to the arithmetic unit and compared with the set temperature of 850 ° C. to produce an output signal, and then the light heating lamp via the output control unit. The output of 6 is controlled. As a result, the semiconductor wafer 1 is quickly and accurately heated to the set temperature, and the ion implantation layer is activated.

Embodiment 2 This embodiment will also be described with reference to FIG. In this embodiment, the semiconductor wafer 1 will be described by taking a silicon wafer on which an insulating layer of a thermal oxide film is formed as an example.

3mm thick silicon carbide / carbon / silicon carbide (SiC / C / Si) with a flat mounting surface and a larger area than the semiconductor wafer.
C) A semiconductor wafer 1 made of silicon is placed on a susceptor 2 having a three-layer structure, held by a holding jig 3 made of transparent quartz, and inserted into a transparent quartz tube 4. Although not shown in FIG. 1, a gas introduction hole and a gas discharge hole are provided at both ends of the transparent quartz tube 4. Oxygen gas is introduced through the gas introduction hole and the transparent quartz tube 4 is introduced through the gas discharge hole. Discharge to the outside. Below the susceptor 2 and outside the transparent quartz tube 4, a light heating lamp 6 by a Xe arc lamp and a reflecting plate 7 are arranged to heat the susceptor 2 from the lower surface, and thereby a semiconductor mounted closely on the susceptor 2 is mounted. The wafer 1 is indirectly heated. The temperature of the semiconductor wafer 1 is measured using a radiation thermometer 5 having a Si detection element which is located outside the transparent quartz tube 4 and is located on the susceptor 2 at a position overlooking the semiconductor wafer 1. Although not shown in FIG. 1, the temperature information output of the radiation thermometer 5 is input to an arithmetic unit and compared with a set temperature of 1200 ° C. to obtain an output signal, and then an optical heating lamp via an output control unit. 6 output control. As a result, the semiconductor wafer 1 is quickly and accurately heated to the set temperature, and an insulating layer made of a thermal oxide film is formed.

Although the embodiments of the present invention have been described above, carbon or silicon carbide alone is used as the material of the susceptor 2.
Alternatively, they may be used in combination as a multi-layer structure, and silicon nitride (Si ₃ N ₄ ) may be used in combination with carbon or silicon carbide to form a multi-layer structure. The point is that a high-purity material that efficiently absorbs the radiant light of the light heating lamp, is stable up to about 1300 ° C., and does not cause contamination of the semiconductor wafer 1 is required. Further, the thickness of the susceptor 2 is preferably 1 mm or more and 5 mm or less, more preferably 2 mm or more and 3 mm or less. This thickness
If it is less than 1 mm, it is mechanically brittle and easily cracks or chips,
In addition, the temperature distribution characteristic becomes worse. In addition, if the thickness exceeds 5 mm, the thermal response characteristics deteriorate, and the purpose of RTA and RTP is defeated.

Further, the shape of the susceptor 2 is wider than that of the semiconductor wafer 1 to be mounted, and the susceptor 2 has a projected area such that the radiant light of the light heating lamp 6 does not directly enter the radiation thermometer 5.

The detection element of the radiation thermometer was used in this example.
In addition to Si, those having sensitivity in the transmission wavelength range of quartz such as Ge, PbS, and PbSe are used.

The light heat treatment apparatus according to the present invention may be used, for example, in the case where the ion implantation layer of InP compound semiconductor is subjected to activation treatment in phosphine (PH ₃ ) gas, in addition to the use described in this embodiment. Is also possible.

[Effect of device]

As described in detail above, the light heat treatment apparatus according to the present invention is
The temperature of a semiconductor wafer mounted on a susceptor with a high efficiency of absorbing radiant light is directly measured and controlled using a radiation thermometer through the wall of a transparent quartz tube, and is interfered by the direct incident light from a light heating lamp. Accurate light heat treatment is possible. Since the thickness of the susceptor is selected to be the optimum value, the thermal response characteristics are also excellent. Compared with the conventional method by thermocouple temperature measurement,
There is no concern about contamination of the semiconductor wafer, and the temperature of the semiconductor wafer itself is measured, so that temperature control is performed accurately.

In addition, compared with the conventional optical heat treatment device that controls the temperature with a radiation thermometer through a viewing window such as CaF ₂ , reliability is improved because there is no adhesive part such as heat resistant adhesive, and arsine, phosphine, etc. are available. The heat treatment using poisonous gas can be performed safely. Furthermore, since the structure of the transparent quartz tube is simple, it is easy to maintain and can be manufactured at low cost. Furthermore, since there are no obstacles between the semiconductor wafer and the radiation thermometer other than the wall of the transparent quartz tube, multipoint temperature measurement / control in a large production furnace by charging many semiconductor wafers This makes a great contribution to the manufacturing process of a semiconductor device, such that the temperature can be easily measured while scanning one semiconductor wafer.

[Brief description of drawings]

FIG. 1 is a view showing a light heating apparatus according to the present invention, and FIG.
FIG. 3 and FIG. 3 are views showing an example of a conventional light heat treatment apparatus,
FIG. 4 is a diagram showing the wavelength range of the transmission wavelength of the detection element of the radiation thermometer, the light source of the light heating lamp, and each material. 1 ... Semiconductor wafer 2 ... Susceptor 3 ... Holding jig 4 ... Transparent quartz tube 5 ... Radiation thermometer 6 ... Optical heating lamp

Claims (1)

[Scope of utility model registration request] 1. A holding jig made of transparent quartz is arranged inside a transparent quartz tube, made of at least one material of carbon and silicon carbide, and having a thickness of 1 mm or more and 5 mm or less, directly bonding a semiconductor wafer. The susceptor to be placed is held by the holding jig, the light heating lamp is placed outside the transparent quartz tube and below the susceptor, and the radiation thermometer is placed outside the transparent quartz tube and the semiconductor wafer. An optical heat treatment apparatus which is arranged at a position where the temperature of the semiconductor wafer is measured and controlled by the radiation thermometer.