JP4557503B2 - Semiconductor device manufacturing method and semiconductor device manufacturing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device manufacturing method and a semiconductor device manufacturing apparatus.
[0002]
[Prior art]
In the manufacturing process of a semiconductor device, a heating process using a rapid heating (RTA) apparatus using a halogen lamp heater or the like as a heat source is widely performed. An example of such a rapid heating process is a ferroelectric memory (FeRAM) capacitor forming process.
[0003]
Currently, dielectric films of ferroelectric capacitors include Pb (Zr _x Ti _1-x ) O ₃ (lead zirconate titanate: PZT), SrBi ₂ Ta ₂ O ₉ (strontium bismuth titanate: SBT), Bi ₃ Ti ₄ O ₁₂ (BIT), (Bi, La) ₄ Ti ₃ O ₁₂ (BLT) or the like is used, and SrRuO ₃ (strontium ruthenate: SRO) or the like is used for the electrode film of the ferroelectric capacitor. ing. When forming a dielectric film or an electrode film using these materials, after depositing an amorphous film on a substrate (wafer) by a sputtering method or a coating method, the amorphous film is crystallized by a rapid heating process.
[0004]
However, when crystallization is performed by rapid heat treatment, certain elements (lead (Pb) in PZT, bismuth (Bi) in SBT, BIT and BLT, ruthenium (Ru) in SRO) are likely to evaporate, There is a problem that it adheres to the wall surface (ceiling) of the heating container (chamber). For this reason, in addition to the problem of deposits falling and causing dust, the deposits block the heating light from the heater (lamp), resulting in uneven temperature distribution within the wafer surface, This causes the problem of temperature fluctuations. These problems are a major factor in reducing the yield and performance of semiconductor devices. For this reason, it is necessary to frequently perform cleaning in order to keep the chamber always clean, but cleaning the chamber requires a great deal of time and labor.
[0005]
In order to solve such a problem, for example, Patent Document 1 proposes a method in which a light-transmissive member is interposed between the wafer and the upper surface of the chamber during the heat treatment. By interposing a heater, it is possible to prevent evaporation from adhering to the chamber. However, since the evaporant adheres to the translucent member, it is difficult to essentially solve the above-described problem.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-289175
[Problems to be solved by the invention]
As described above, in the conventional heating method and heating apparatus, the evaporation generated by the heat treatment adheres to the upper surface of the chamber and blocks the heating light from the heater, and thus the temperature distribution on the substrate becomes uneven. There was a problem that the temperature fluctuated between the substrates. Therefore, there has been a problem that the substrate cannot be heated properly and the yield and performance of the semiconductor device are lowered.
[0008]
The present invention has been made to solve the above-described conventional problems, and can provide a method for manufacturing a semiconductor device and a semiconductor device capable of appropriately heating a substrate and preventing a decrease in yield and performance of the semiconductor device. The object is to provide a manufacturing apparatus.
[0009]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a method for manufacturing a semiconductor device, including a step of placing a substrate having a processing target in a first region in a light-transmitting container, and a third directly above the first region. And heating the substrate with the heating light supplied from the second region directly below the first region without supplying the substrate with heating light from the region. .
[0010]
A semiconductor device manufacturing apparatus according to a second aspect of the present invention includes a translucent container that includes therein a first region in which a substrate is disposed, and a substrate disposed in the first region. A heating unit for generating heating light, which is provided at least in the second region directly below the first region, but not provided in the third region directly above the first region. And a heating unit.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0012]
FIG. 1 is a diagram schematically showing a schematic configuration of a semiconductor device manufacturing apparatus (rapid heating (RTA) apparatus) according to an embodiment of the present invention.
[0013]
A susceptor 12 and a thermometer 13 are fixed to the susceptor fixing base 11, and a wafer (semiconductor substrate) 14 and a partition plate 15 can be mounted on the susceptor 12. The wafer 14 is disposed on the susceptor 12 with the element formation surface facing upward, and the distance between the wafer 14 and the partition plate 15 is set to about 1 cm or less. The partition plate 15 has an area larger than that of the wafer 14, and for example, a translucent member such as quartz glass is used. The susceptor fixing base 11 can be moved between the wafer loader part 1 and the processing part 2 by a roller 16, and the susceptor fixing base 11 is in close contact with the chamber (translucent container) 17 as shown in FIG. The chamber 17 is hermetically sealed.
[0014]
A heating unit 18 composed of, for example, a halogen lamp heater (heat source) is disposed outside the chamber 17 so that the wafer 14 mounted on the susceptor 12 can be heated. For the chamber 17, a translucent member such as quartz glass is used so that the heating light (infrared rays) from the heating unit 18 can be transmitted.
Further, the chamber 17 is provided with a gas inlet 19 and a gas outlet (not shown) arranged on the opposite side of the gas inlet 19, and supplies various gases into the chamber 17 in the heat treatment process. Is possible.
[0015]
In the example of FIG. 1, the heating unit 18 is disposed on the lower side of the chamber 17, but is not disposed on the upper side of the chamber 17. The heating unit 18 may be at least in the region A2 immediately below the region A1 (region corresponding to the outer periphery of the wafer) where the wafer 14 is disposed, but as shown in FIG. 1, the heating unit 18 also heats the region outside the region A2. It is preferable that the part 18 is provided.
[0016]
Moreover, although the heating part 18 may be comprised with the single heater, it may be comprised with several heaters of a dotted | punctate shape or linear (bar shape), and it may enable it to adjust the output of each heater. FIG. 2 is a diagram schematically showing an example of the heater arrangement pattern. In this example, a plurality of dotted heaters 18a are arranged inside and outside the region A2.
[0017]
Since the processing target to be subjected to the heat treatment is formed on the upper surface (element formation surface) of the wafer 14, the evaporated substance by the heat treatment adheres to the upper surface of the chamber and hardly adheres to the lower surface of the chamber. When the heating unit is also provided on the upper side as in the past, the heating light from the upper heating unit is blocked by the adhering material adhering to the upper surface of the chamber, and the temperature distribution in the wafer surface is uneven. And a problem that the temperature varies (varies) between wafers. In the apparatus of the present embodiment, the heating unit is not provided on the upper side of the chamber 17, and the wafer 14 is heated by the heating unit 18 provided on the lower side of the chamber 17. However, the above-described problem does not occur, and the substrate can be appropriately heated.
[0018]
In the present embodiment, since the heating unit 18 is provided with a plurality of heaters, it is possible to improve the uniformity of the temperature distribution in the wafer 14 surface. In particular, by adjusting the output of each heater, the temperature distribution can be adjusted accurately, and the uniformity of the temperature distribution can be further improved.
[0019]
In addition, since heat treatment is performed with the partition plate 15 interposed between the wafer 14 and the upper surface of the chamber, it is possible to prevent evaporation from adhering to the upper surface of the chamber.
Even if the evaporated material adheres to the partition plate 15, the partition plate 15 can be easily replaced and cleaned, so that the cleanliness can be kept relatively high. Therefore, by interposing the partition plate 15, it is possible to avoid the problem that deposits fall on the wafer 14.
[0020]
Hereinafter, an example of the case where the above-described heat treatment apparatus is used in a semiconductor device manufacturing process will be described. Here, a case where the above-described heat treatment apparatus is used for the capacitor forming process of the ferroelectric memory will be described as an example.
[0021]
FIG. 3 is a cross-sectional view schematically showing an example of the configuration in the vicinity of the element formation surface of the wafer 14 that is subjected to the heat treatment by the heat treatment apparatus described above.
[0022]
A lower electrode film 34a, a dielectric film 34b, and an upper electrode film 34c, which are constituent films of a ferroelectric capacitor, are formed on the semiconductor substrate 31 on which the transistor 32, the interlayer insulating film 33, and the like are formed. The dielectric film 34b, a perovskite compound _{Pb (Zr x Ti 1-x} ) O 3 ( lead zirconate titanate: PZT) or bismuth layered compound SrBi ₂ Ta ₂ O ₉ (strontium titanate bismuth: SBT ), Bi ₃ Ti ₄ O ₁₂ (BIT), (Bi, La) ₄ Ti ₃ O ₁₂ (BLT) and other ferroelectric films can be used, and the lower electrode film 34a and the upper electrode film 34c are made of perovskite. A compound such as SrRuO ₃ (strontium ruthenate: SRO) can be used.
[0023]
In the example of FIG. 3, the lower electrode film 34a and the dielectric film 34b are already heated and crystallized, and an amorphous upper electrode film 34c is formed on the dielectric film 34b as a process target. . Note that the wafer subjected to the heat treatment does not have to be a state where all of the lower electrode film 34a, the dielectric film 34b, and the upper electrode film 34c are formed, and only the lower electrode film 34a in an amorphous state is processed. May be formed, or an amorphous upper electrode film 34c may be formed as a processing target on the crystallized lower electrode film 34a.
[0024]
In the above-described compounds such as PZT, SBT, BIT, BLT and SRO, during the heat treatment, specific elements contained in the compound (lead (Pb) in PZT, bismuth (Bi) in SBT, BIT and BLT, SRO) Then, ruthenium (Ru) is more easily evaporated than other elements contained in the compound. Therefore, it is effective to use the heating apparatus and heating method of this embodiment.
[0025]
First, the susceptor 12 is moved to the wafer loader unit 1, the partition plate 15 is placed on the susceptor 12, and a carrier (not shown) containing the wafer 14 is placed on the wafer loader unit. When a preset program is activated, an arm (not shown) takes out the wafer 14 from the carrier and places it on the susceptor 12 with the element formation surface of the wafer 14 facing upward.
[0026]
Next, the susceptor fixing base 11 is moved to the processing unit 2 and brought into close contact with the chamber 17, and the susceptor 12 on which the wafer 14 and the partition plate 15 are mounted is disposed in the chamber 17. Subsequently, a predetermined gas is supplied into the chamber 17 from the gas supply port 19. Further, the lamp heater of the heating unit 18 is turned on to heat the wafer 14 at a predetermined temperature for a predetermined time. The heating temperature is a predetermined temperature between 400 ° C. and 750 ° C., for example. At this time, the specific element included in the processing target evaporates and adheres to the partition plate 15, but the heating unit is not disposed on the upper side of the chamber 17, so there is no influence of the attached matter. During the heat treatment, the substrate temperature is monitored by the thermometer 13 and the output of the heater is adjusted.
[0027]
When the heat treatment is completed, the susceptor fixing base 11 is moved to the wafer loader unit 1. Further, the arm 14 picks up the wafer 14 from the susceptor 12, cools the wafer 14, returns it to the carrier, and completes a series of processes.
[0028]
FIG. 4 is a diagram schematically showing a schematic configuration of a modified example of the manufacturing apparatus shown in FIG. The basic configuration is the same as that of the apparatus shown in FIG. 1, and the components corresponding to those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0029]
In the example shown in FIG. 1, the heating unit is not arranged above the chamber 17, but in the example shown in FIG. 4, the heating unit 20 is also arranged above the chamber 17. However, as shown in FIG. 4, the heating unit 20 is not disposed in the region A3 immediately above the region A1 where the wafer 14 is disposed, and is disposed, for example, in a ring shape in a region outside the region A3. Yes. The heating unit 18 may be configured by a single heater, but may be configured by a plurality of dotted or linear (bar-shaped) heaters so that the output of each heater can be adjusted. Further, the output of the heating unit 20 is preferably 30% or less of the total output of the heating unit 18 and the heating unit 20.
[0030]
Generally, heat easily escapes at the outer edge portion of the wafer 14, and thus the temperature tends to decrease. In the example of FIG. 4, since the heating unit 20 is provided in a region outside the region A3, more heating light can be supplied to the outer edge portion than the central portion of the wafer 14, and the temperature drop at the outer edge portion can be reduced. Can be prevented. Further, a large amount of the evaporated material from the wafer 14 adheres to the region directly above the wafer 14 and the amount of adhesion to the outer region is small. In this example, since the heating part 20 is provided in the area | region outside area | region A3, the degree to which heating light is interrupted by the deposit | attachment is very small. Therefore, it is possible to effectively supply the heating light to the outer edge portion of the wafer 14 without being substantially affected by the deposits, and the temperature distribution in the wafer surface can be made uniform.
[0031]
Hereinafter, some measurement examples for verifying the effect of the present embodiment will be described. The sample used for the measurement is an SRO film formed by sputtering on a platinum film formed on a silicon wafer.
[0032]
As measurement example 1 (comparative example), measurement was performed using a heat treatment apparatus as shown in FIG. In the apparatus of FIG. 5, the heating unit 21 is also provided in the region A <b> 3 above the chamber 17. The heat treatment was performed at a temperature of 650 ° C. for 30 seconds while flowing oxygen gas at a flow rate of 5 liters / minute. The temperature distribution in the wafer surface was measured before processing and after processing 69 wafers. FIG. 6 shows the measurement results.
[0033]
As can be seen from the result of the temperature difference (maximum temperature-minimum temperature), the temperature uniformity in the wafer surface does not change greatly before and after the processing, but the average temperature in the wafer surface is higher than that before the processing. After the treatment, the temperature drops by 14 ° C. This is because the heating light from the heating unit 21 is shielded by the deposits on the partition plate 15, which means that the temperature variation between the wafers increases.
[0034]
As measurement example 2 (comparative example), measurement was performed using a heat treatment apparatus as shown in FIG. However, the partition plate 15 was not installed. The heat treatment conditions were the same as in Measurement Example 1, and the number of wafers was 43. FIG. 7 shows the measurement results.
[0035]
As can be seen from the result of the temperature difference, the temperature difference is 56 ° C. after the processing, and the uniformity of the temperature distribution in the wafer surface is greatly deteriorated. This is because the evaporant flows along the flow of oxygen gas, and as a result, more evaporant adheres to the ceiling of the chamber 17 on the gas outflow side than on the gas inflow side, and the heating light on the gas outflow side. This is because the transmittance of the liquid crystal deteriorated significantly.
[0036]
As Measurement Example 3, measurement was performed using a heat treatment apparatus as shown in FIG. The heat treatment conditions and the number of wafers are the same as in Measurement Example 1. FIG. 8 shows the measurement results.
[0037]
The minimum temperature, the maximum temperature, and the average temperature hardly change before and after the process, and the temperature fluctuation between the wafers is greatly reduced. Note that the temperature difference in the wafer surface is large both before and after processing, and the temperature distribution in the wafer surface is uneven. This is because a rod-like heater is used for the heating unit 18. If the output of each heater is adjusted using a plurality of spot heaters as shown in FIG. 2, it is possible to improve the uniformity of the temperature distribution in the wafer surface.
[0038]
As measurement example 4, the measurement was performed using a heat treatment apparatus as shown in FIG. The heat treatment conditions and the number of wafers are the same as in Measurement Example 1. FIG. 9 shows the measurement results.
[0039]
The minimum temperature, the maximum temperature, and the average temperature hardly change before and after the process, and the temperature fluctuation between the wafers is greatly reduced. Further, the temperature difference within the wafer surface is about 12 to 13 ° C. both before and after the processing, and the uniformity of the temperature distribution within the wafer surface is also good. This is because the temperature reduction at the outer edge portion of the wafer 14 is suppressed because the heating unit 20 is provided in the region outside the region A3.
[0040]
In the above-described embodiment, as shown in FIGS. 1 and 4, the heating unit is not provided in the area A <b> 3 immediately above the area A <b> 1 where the wafer 14 is disposed, but for example, as illustrated in FIG. 5. Even if the apparatus provided with a heating unit in the area A3, if the heater in the area A3 is not turned on during the heat treatment, the heat treatment is performed using the apparatus shown in FIG. 1 or FIG. It is possible to obtain an effect similar to the effect of.
[0041]
In the above-described embodiment, the capacitor electrode film or the dielectric film is described as an example of the processing target, but the processing target is not limited to these. For example, a method similar to that of the above-described embodiment can be applied to a heat treatment after ion implantation of impurities such as phosphorus into a semiconductor substrate.
[0042]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining the disclosed constituent elements. For example, even if several constituent requirements are deleted from the disclosed constituent requirements, the invention can be extracted as an invention as long as a predetermined effect can be obtained.
[0043]
【The invention's effect】
According to the present invention, it is possible to appropriately heat the substrate, and it is possible to prevent a decrease in yield and performance of the semiconductor device.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a schematic configuration example of a semiconductor device manufacturing apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram schematically showing an example of an arrangement pattern of heaters.
FIG. 3 is a cross-sectional view schematically showing a configuration example in the vicinity of an element formation surface of a wafer to be heat-treated.
FIG. 4 is a diagram schematically showing a schematic configuration example of a semiconductor device manufacturing apparatus according to a modification of the embodiment of the present invention.
FIG. 5 is a diagram schematically showing a schematic configuration example of a semiconductor device manufacturing apparatus according to a comparative example of an embodiment of the present invention.
FIG. 6 is a diagram showing measurement results for verifying the effect of the embodiment of the present invention.
FIG. 7 is a diagram showing measurement results for verifying the effect of the embodiment of the present invention.
FIG. 8 is a diagram showing measurement results for verifying the effect of the embodiment of the present invention.
FIG. 9 is a diagram showing measurement results for verifying the effect of the embodiment of the present invention.
[Explanation of symbols]
1 ... wafer loader unit, 2 ... processing unit,
11 ... susceptor fixing base, 12 ... susceptor,
13 ... Thermometer, 14 ... Wafer,
15 ... partition plate, 16 ... roller,
17 ... Chamber, 18, 20, 21 ... Heating part,
19 ... gas inlet, 31 ... semiconductor substrate,
32 ... transistor 33 ... interlayer insulating film,
34a ... lower electrode film, 34b ... dielectric film,
34c ... Upper electrode film

Claims (4)

Disposing a substrate having a processing target in a first region in the translucent container;
The heating light supplied from the second region directly below the first region and the third region without supplying heating light to the substrate from the third region directly above the first region. Heating the substrate with heating light supplied from a heating unit arranged in a ring shape in the outer region of
A method for manufacturing a semiconductor device, comprising: The semiconductor device according to claim 1, wherein the object to be processed is a perovskite compound or a bismuth layered compound, and a specific element contained in the compound is more easily evaporated than other elements contained in the compound. Method. A translucent container containing therein a first region in which a substrate is disposed;
A heating unit that generates heating light for heating the substrate disposed in the first region, and is provided in at least a second region directly below the first region. A heating unit not provided in the third region directly above the region;
Another heating unit provided in a region outside the third region and arranged in a ring shape that generates heating light for heating the substrate;
An apparatus for manufacturing a semiconductor device, comprising: The apparatus for manufacturing a semiconductor device according to claim 3 , wherein a partition plate can be interposed between the substrate and the upper surface of the translucent container.

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