JP2000297276A - Heater and heating method for semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for heating a semiconductor in high yield, capable of carrying out uniform heat treatment in a short time without almost being affected by the surface state, or the like, of a semiconductor, or the like, and a heating method therefor. SOLUTION: This heater 10 for semiconductors is equipped with a crucible 1 constituted of a heat-insulating material and a heater 2 arranged in the crucible 1. Liquid-like Zn 3 is put in the crucible 1 and heated by the heater 2. Then, the liquid-like Zn 3 is evaporated and the evaporated Zn 4 is stored in the upper part of the crucible 1. An opening and closing valve 5 and a nozzle 6 are installed in the crucible 1. The evaporated Zn 4 is sprayed through the opening and closing valve 5 from the nozzle 6. Then, Zn 7 jetted from the nozzle 6 is sprayed to a sample 9. The sample 9 is installed in a holder 8 and heated by a heater 11 installed in the holder 8. The jetted Zn (gas) is attached onto the sample 9 and heat of condensation is imparted to the sample 9. Thereby, heat treatment of the sample 9 can be carried out in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a manufacturing apparatus and a manufacturing process used for manufacturing semiconductor products, liquid crystal display devices, and the like.

[0002]

2. Description of the Related Art As semiconductor integrated circuits become smaller,
It is necessary to reduce the diffusion distance of impurities in a semiconductor material, and therefore, in a heat treatment process such as activation of impurities,
There is a need for a method of shortening the diffusion distance of impurities at a low temperature or by shortening the time. In order to shorten the heat treatment process, it has been proposed that the semiconductor material is irradiated with a Xe arc lamp to perform the heat treatment in a time period of several seconds to several minutes.

Further, in a process of manufacturing a liquid crystal display device using a low-temperature polysilicon (poly-Si) TFT which has been developed in recent years, a glass substrate which is weak against heat is used. And heating only the semiconductor film formed on the substrate to form amorphous silicon (amor).
It is necessary to crystallize from the silicon-containing (phos-Si) into polysilicon and to activate impurities introduced into the film. Therefore, a method of performing heating on the order of 10 ⁻⁹ seconds using an excimer laser (Excimer Laser Annnea)
A method of performing heating for several seconds or less using a ring method (ELA) or a Xe arc lamp (Rapid T)
thermal Annealingmethod: R
TA) is used.

[0004]

However, the ELA method and R
The heating method by light irradiation using the TA method is not only expensive in equipment and running costs, but also in the shape, density, type, thickness, and lamination state of patterns formed on semiconductor wafers and glass substrates. Therefore, there is a problem that it is difficult to perform a uniform heat treatment due to the strong influence of the heat treatment. In particular,
There is a problem that uniform heat treatment is difficult depending on the presence or absence of a gate electrode having a bottom gate structure.

Further, it is difficult to determine processing conditions, and there is a problem that a process margin is small and a yield is low.

Therefore, the present invention solves such a problem,
An object of the present invention is to provide a heating device and a heating method which are hardly affected by the surface state of a semiconductor or the like, are uniform in a short time, and have a high yield.

[0007]

According to the first aspect of the present invention, there is provided a medium for emitting heat of transformation, a material to be heated maintained at a temperature lower than that of the medium, and a medium in contact with the material to be heated. And a contact heating means.

In the semiconductor heating apparatus according to the first aspect, a medium that emits transformation heat is brought into contact with the material to be heated by the contact means, and the material to be heated is heated by the transformation heat from the medium. The substance to be heated undergoes a phase change in accordance with the amount of transformation heat from the medium, or the impurities in the substance to be heated are activated.

Therefore, according to the first aspect of the present invention, only by bringing the medium into contact with the substance to be heated, the transformation heat is transferred from the medium to the substance to be heated, and the heat treatment can be performed in a short time.

According to a second aspect of the present invention, there is provided a medium, a heating means for heating the medium to a temperature at which the transformation heat can be released, and a heated medium maintained at a temperature lower than the temperature at which the medium can release the transformation heat. A semiconductor heating apparatus comprising: a substance; and a contact unit configured to contact a medium heated to a temperature at which the transformation heat can be released by the pretreatment unit, with the medium to be heated.

In the semiconductor heating apparatus according to the second aspect, the medium is heated to a temperature at which the transformation heat can be released by the heating means, and the heated medium is brought into contact with the substance to be heated by the contact means. Then, since the temperature of the substance to be heated is lower than the temperature of the medium, the transformation heat is transferred from the medium to the substance to be heated, and the substance to be heated undergoes a phase change due to the transformation heat, or the impurities contained therein are activated. .

Therefore, according to the second aspect of the present invention, the medium is heated to a temperature at which the transformation heat can be released, and the heated medium is brought into contact with the substance to be heated. The impurities in the substance to be heated can be activated, and heat treatment can be performed in a short time.

According to a third aspect of the present invention, there is provided the semiconductor heating apparatus according to the first or second aspect,
Transformation heat is a semiconductor heating device that is heat of solidification or heat of condensation.

In the semiconductor heating apparatus according to the third aspect, when the medium is brought into contact with the substance to be heated, heat of solidification or heat of condensation is transferred from the medium to the substance to be heated, and the phase change of the substance to be heated, Alternatively, activation of impurities in the substance to be heated is performed.

Therefore, according to the third aspect of the present invention, the phase change of the material to be heated or the activation of impurities in the material to be heated can be achieved only by melting the medium and bringing the medium into contact with the material to be heated. It is.

According to a fourth aspect of the present invention, there is provided a first step of heating a medium to a temperature at which transformation heat can be released;
And a second step of bringing the medium heated in step (c) into contact with the substance to be heated.

[0017] In the semiconductor heating method according to the fourth aspect, in the first step, the medium is heated to a temperature capable of releasing transformation heat. Then, in the second step, the medium heated in the first step is brought into contact with the substance to be heated, the transformation heat is transferred from the medium to the substance to be heated, and the substance to be heated is heated.

Therefore, according to the fourth aspect of the present invention, the heat treatment of the material to be heated can be performed by a simple method.

According to a fifth aspect of the present invention, in the method of heating a semiconductor according to the fourth aspect, the transformation heat is a method of heating the semiconductor, which is heat of solidification or heat of condensation.

According to a fifth aspect of the present invention, in the semiconductor heating method, in the first step, the medium is heated to a temperature capable of releasing heat of solidification or condensation, and in the second step, the medium to be heated is discharged from the medium. The heat of solidification or the heat of condensation moves to heat the substance to be heated.

According to the fifth aspect of the present invention, the material to be heated can be easily heated only by melting the medium and bringing the medium into contact with the material to be heated.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. With reference to FIG. 1, a semiconductor heating device according to the present invention will be described. Semiconductor heating device 10
Comprises a crucible 1 made of a heat insulating material, and a heater 2 arranged in the crucible 1. The crucible 1 contains a liquid Z
n3 is inserted and heated by the heater 2. Then, the liquid Zn3 is vaporized, and the vaporized Zn4 accumulates on the upper part of the crucible 1. The crucible 1 has an on-off valve 5 and a nozzle 6
The vaporized Zn 4 is ejected from the nozzle 6 through the on-off valve 5. Then, the Zn 7 ejected from the nozzle 6 is sprayed on the sample 9. The sample 9 is set on the holder 8 and is heated by a heater 11 provided in the holder 8. In addition, holder 8
Is movable in the directions of arrows 16 and 17. The atmosphere 18 in which the sample 9 is placed is surrounded by a container 19, and the container 12 is provided with a cylinder 12.
3. They are connected via a pipe 14. And cylinder 1
The Ar gas in 2 is guided into the vessel 19 from the emission port 15 through the regulator 13 and the pipe 14, and the atmosphere 18 is A
A predetermined pressure is satisfied by the r gas. By filling the atmosphere 18 of the container 19 with an inert gas, oxidation during the heat treatment of the sample 9 can be prevented, and at the same time, the boiling point of Zn can be controlled by the pressure of the atmosphere by the inert gas.

The activation of a polysilicon film on a glass substrate using the heat of condensation of Zn will be described with reference to FIGS. When the activation of the polysilicon film is performed, the sample 9 is provided with polysilicon formed on the substrate.

Referring to FIG. 2A, as the polysilicon 22 as the sample 9, amorphous silicon having a thickness of 50 nm is formed on a glass substrate 20 by a plasma CVD method, and crystallized by an ELA method. Then, patterning is performed. Then, using an ion doping apparatus, phosphorus (P) atoms are implanted at a ^dose of 1 × 10 ⁺¹⁵ cm ⁻² at an energy of 30 keV. Then, plasma C
500 V of silicon oxide film (SiO ₂ ) 21 by VD method
nm. Then, Zn at 1100 ° C. is injected from the nozzle 6 of the crucible 1 of FIG. 1 for 0.1 second. In this case, the atmosphere 18 of the container 19 is pressurized to 5 atoms, and the polysilicon 22 is heated to 400 ° C. by the heater 11.
Heating. The boiling point of Zn at 5 atm is 1
At 080 ° C., the heat of condensation is 95 kJ / mol.

Here, consider the temperature distribution inside the glass substrate when the surface of the glass substrate heated to 400 ° C. is instantaneously raised to 1080 ° C.

Generally, the temperature change due to heat conduction inside the material to be heated is Tt: phase transformation temperature of the heating medium material Ts: substrate temperature α: κ / ρ · c κ: thermal conductivity coefficient 1: substrate thickness t: time x: depth

Therefore, a glass substrate heated to 400 ° C.
Glass base when surface of glass is instantaneously raised to 1080 ° C
The figure shows the temperature distribution inside the plate calculated using the above equation (1).
It looks like 3. According to FIG. 3, the surface of the glass substrate was 1080
The amount of heat required to hold for 0.1 seconds at
Heat 0.78J / g · k, density 2.54g / cm^ThreeWhen
And 40 J / cm per unit area^TwoBecomes On the other hand, Z
n at 5 atom, heat of condensation at 1080 ° C is about 95k
J / mol, 40/9500 per unit area
0 = 4.2 × 10^-Fourmol / cm^TwoSample table of Zn
What is necessary is to vapor-deposit on a surface. Therefore, the deposited Z
The film thickness of n is 4.2 × 10^-Fourmol / cm ^Two× 64.4
(G / mol) /7.14 (g / cm^Three) = 3.8 × 1
0^-Five(Cm) = 38 (μm).

Therefore, the heater 1 is supplied from the nozzle 6 shown in FIG. 1 in an atmosphere 18 pressurized to 5 atoms with Ar.
Polysilicon 22, 22 heated to 400 ° C. by step 1
Zn at 1080 ° C. is sprayed onto / SiO ₂ so as to have a film thickness of 38 μm. In this case, 400 μm of Zn per second
Zn (gas) is jetted from the nozzle 6 under the condition of 300 sccm so that the (liquid) is deposited in a circular shape having a diameter of about 1 cm, and the holder 8 moves the arrows 16 and 1 at a speed of 10 cm / s.
7 is moved. And the deposited Zn (gas)
Is cooled on the SiO ₂ (21) surface and condensed into Zn (liquid), and heat of condensation is given to the polysilicons 22 from the Zn (gas) via the SiO ₂ (21). And
Phosphorus (P) atoms introduced into polysilicons 22 by ion doping are electrically activated. The Zn (liquid) deposited on the polysilicon 22, 22 / SiO ₂ surface changes from liquid to solid Zn when cooled to around 400 ° C. (see FIG. 2B).

After the atmosphere 18 is cooled down to room temperature, the polysilicon 22, 22 / SiO ₂ to which solid Zn is adhered is taken out and immersed in a mixture of sulfuric acid and hydrogen peroxide at 135 ° C. to remove the solid Zn23. . And S by HF
iO ₂ Results of measurement of the sheet resistance of the polysilicon 22 and 22 after removal of the average 380Ω / □ (Min: 365
Ω / □, maximum: 405 Ω / □), which indicates that the sheet resistance is reduced by about 25% as compared with the conventional RTA method. Further, as can be seen from FIG. 3, since about 2/3 of the glass substrate has a temperature rise of 200 ° C. or less, the damage to the substrate glass is lower than that of the conventional RTA method (heating time: 100 seconds). Also less.

With reference to FIGS. 1 and 4, the production of a TFT utilizing the heat of solidification of sprayed Si will be described.

Amorphous silicon layers 30 and 30 having a thickness of 50 nm are deposited on the substrate by a plasma CVD method and patterned into a predetermined pattern. Then, 100 n of SiO ₂ 31 is formed so as to cover the amorphous silicon layers 30 and 30.
m, deposited by a plasma CVD method (see FIG. 4A). Then, in the crucible 1 of FIG. 1, Si containing 2 wt% of phosphorus (P) is heated to 1410 ° C. or higher by the heater 2 and melted.
Inject onto O ₂ 31 (see FIG. 4 (b)).

In this case, the temperature distribution inside the glass substrate when Si at 1410 ° C. is instantaneously applied is calculated as shown in FIG. From FIG. 5, the annealing time was set to 0.1 second on the basis that about 1/2 of the glass substrate does not exceed the glass strain point (600 to 650 ° C.). Also, from the temperature distribution after 0.1 seconds in FIG. 5, the amount of heat required per 1 cm ^{2 of} the substrate can be calculated as 56.2 J / cm ² . On the other hand, S
i of heat of solidification is 456kJ / mol, the atomic weight of Si: 28.086, Density: Given the 2.33 g / cm ^3, heat of solidification per Si1cm ³ is 37.8kJ / c
m is ^3. Therefore, 56.2 J / cm per 1 cm ²
The thickness of Si required to generate the heat of ² is 56.2 /
37.8 × 10 ³ = 1.49 × 10 ⁻³ cm = 15 μm.

Therefore, 15 μm of Si on the SiO ₂ 31
From the nozzle 6 such that molten Si (1500) is deposited.
° C) 32. Then, heat of solidification is given to the amorphous silicon 30 from the Si 33 deposited on the SiO ₂ 31, and the amorphous silicon 30 is
4 (see FIGS. 4B and 4C).

After crystallizing the amorphous silicon 30 into the polysilicon 34, the silicon deposited on the SiO ₂ 31 is patterned into an island shape, and P ⁺ ions are applied at an energy of 100 keV to 1 × 10 ¹⁵ cm ^−. Inject ² Then, the SiO ₂ was 450nm deposited as an interlayer insulating film on the island-shaped Si35,35, activates the source and drain regions using the condensation heat of Zn as described above. After removing Zn remaining on the surface with a mixed solution of sulfuric acid and hydrogen peroxide solution, Al
And an n-ch TFT with W / L = 100/100 (μm) was manufactured. The characteristics of the TFT are as follows: electric field mobility μ = 185 cm ² / V · s, Vth = 0.2 V, S =
0.02 V / dec. Met.

It is also possible to manufacture a TFT having a thin gate electrode by using projection Si. Assuming that the thickness of the gate electrode is 300 nm, the heat of solidification of 300 nm Si per 1 cm ² is 37.8 (kJ / cm ³ ) × 0.3 × 1.
0 ⁻⁴ cm = 1.134 J / cm ² . The same sample as that shown in FIG. 2A was prepared, and a sample having a nozzle diameter of 1.5 mm was scanned at a substrate scanning speed of 1.2 m / s.
i was applied and 300 nm of Si was deposited. in this case,
Thermal spray Si contains 2 wt% of P atoms. Then, after the sprayed Si was converted into islands, 100 keV P ⁺ ions and 35 keV B ⁺ ions were respectively added to 1 × 10 ¹⁵
Ion implantation is performed individually using an implantation mask at a ^{dose of} cm ⁻² and 5 × 10 ¹⁴ cm ⁻² . Thereafter, an interlayer insulating film is formed, and Zn
Was activated in the same manner as described above, and Al wiring was provided.

The characteristics of the TFT are n-ch TFT (W / L
= 10/5 (μm) and μ = 140 cm ² / V · s, Vt
h = 0.35V, S = 0.04V / dec. And p
-Ch TFT (W / L = 20/5 (μm) and μ = 75c)
m ² / V · s, Vth = −1.0 V, S = 0.15 V /
dec. Met. Since it is necessary to control Vth in order to use it in an actual circuit, the n-ch TFT has B
⁺ Ions at 1.5 × 10 ¹² cm ^-2 , P ⁺
Ions were implanted at 1.5 × 10 ¹² cm ⁻² each before the gate electrode was fabricated by spraying. As a result, Vth
Became 1.9 V and -2.8 V, respectively. The oscillation frequency of the ring oscillator thus manufactured was 13.5 MHz for an input of 15 V.

The MIC effect utilizing the heat of solidification of Ni will be described with reference to FIG. As shown in FIG. 6A, an amorphous silicon layer 51 is provided, and at both ends, doped amorphous silicon layers 51 and 51 serving as a source and a drain are present. SiO ₂ is formed on the amorphous silicon layers 51 and 51 so as to surround the gate electrode 53.
The contact hole CH is formed in the laminated structure in which the layer 52 is provided.
1, CH2 and CH3 are formed. Then, after forming contact holes CH1, CH2, CH3, FIG.
As shown in FIG. 7, the amorphous silicon layer 51 and the doped amorphous silicon layers 51, 51 are crystallized using the MIC effect of Ni (catalytic effect of Ni) by spraying the molten Ni 54 to form polycrystalline silicon (po).
ly-Si) 55, 56, 56.
The melting point of Ni is 1455 ° C. By using the process as shown in FIG. 6, the crystallization of amorphous silicon can be used, and Ni formed by irradiation can be used as a wiring, and the process can be simplified.

As described above, by instantaneously heating Si using the heat of condensation of Zn and the heat of solidification of Si,
Amorphous silicon can be crystallized into polysilicon, and impurity atoms such as P atoms and B atoms in silicon can be electrically activated.

[Brief description of the drawings]

FIG. 1 is a schematic view of a semiconductor heating apparatus according to the present invention.

FIG. 2 is a diagram illustrating activation using heat of condensation of Zn.

FIG. 3 is a temperature distribution inside the glass when heat of condensation of Zn is given.

FIG. 4 is a diagram illustrating crystallization using heat of solidification of Si.

FIG. 5 is a temperature distribution inside glass when heat of solidification of Si is given.

FIG. 6 is a diagram illustrating the MIC effect of Ni.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Crucible 2, 11 ... Heater 3 ... Melted Zn 4 ... Vaporized Zn 5 ... On-off valve 6 ... Nozzle 7 ... Injection Zn 8 ... Holder 9 ...・ Sample 10 ・ ・ ・ Heating device 12 ・ ・ ・ Cylinder 13 ・ ・ ・ Regulator 14 ・ ・ ・ Piping 15 ・ ・ ・ Emission port 16, 17 ・ ・ ・ Arrow 18 ・ ・ ・ Atmosphere 19 ・ ・ ・ Container 20 ・ ・ ・Substrates 21, 31, 53: SiO ₂ 22, 34, 55, 56: polysilicon 50, 51: amorphous silicon 54: nickel

Claims (5)

[Claims] An apparatus for heating a semiconductor, comprising: a medium that emits transformation heat; a substance to be heated maintained at a lower temperature than the medium; and contact means for bringing the medium into contact with the substance to be heated. 2. A medium, heating means for heating the medium to a temperature capable of releasing transformation heat, a material to be heated maintained at a temperature lower than a temperature at which the medium can emit transformation heat, and the heating means Contacting means for bringing a medium heated to a temperature capable of releasing transformation heat into contact with the substance to be heated. 3. The semiconductor heating apparatus according to claim 1, wherein the transformation heat is heat of solidification or heat of condensation. 4. A method for heating a semiconductor, comprising: a first step of heating a medium to a temperature at which transformation heat can be released; and a second step of bringing the medium heated by the first step into contact with a substance to be heated. Method. 5. The semiconductor heating method according to claim 4, wherein said transformation heat is heat of solidification or heat of condensation.