KR20050109448A - Equipment and method for manufacturing semiconductor device - Google Patents

Abstract

Equipment of manufacturing a semiconductor device, wherein a load lock chamber (12) is connected to the front stage of a film forming chamber (11) through a damper, a pipe for feeding N2 gas and gases or foggy H2O coming from a vaporizer (13) is connected to the load lock chamber (12), a carrying part (15) for placing a wafer thereon is installed in the load lock chamber (12) and a cooler (14) for cooling the carrying part (15) by using liquid nitrogen is disposed on the outside of the load lock chamber (12), and the temperature of the carrying part (15) is held, for example, at -4 °C.

Description

Manufacturing apparatus and manufacturing method of a semiconductor device {EQUIPMENT AND METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE}

The present invention relates to a manufacturing apparatus and a manufacturing method of a semiconductor device suitable for forming a ferroelectric capacitor or Al wiring.

In ferroelectric capacitors used in ferroelectric memories and the like, when the orientations (<111>, <222>, etc.) of the capacitor films (LiTaO ₃ film, Pb (Zr, Ti) O ₃ (PZT) film, etc.) become stronger, It is known that the characteristics of the capacitors are improved. For this reason, although the orientation improvement was aimed at by optimization of the film-forming conditions and annealing conditions of the capacitor film itself conventionally, the method of improving the orientation more effectively is calculated | required in recent years.

In response to this request, it is known that the stronger the C-axis orientation (<002>, <001>, etc.) is, the stronger the four-side orientation of the capacitor film is in the crystal orientation of the lower electrode of the planar ferroelectric capacitor. The method of strengthening the C-axis orientation of an electrode is also examined.

In addition, for Al wirings used in various semiconductor devices, a base metal film is formed to improve migration resistance, and in order to obtain high effects, high orientation and thickening are achieved. ) Is being requested.

As materials of these lower electrodes and the base metal film, high melting point metals such as Ti and Ta are mainly used, and these are generally formed by DC magnetron sputtering or the like. In addition, in order to improve the C-axis orientation of the base metal film, there is also a method of mixing water with a sputtering gas (Ar gas).

However, when the Ti film is formed by the DC magnetron sputtering method, the orientation of Ti may change depending on the attained vacuum degree of the film forming chamber, the number of processing lots, and the like.

In addition, sufficient orientation cannot be obtained only by mixing moisture in the sputtering gas. In addition, when moisture adheres to the jig of the film formation chamber, this moisture causes an arc-plasma and the discharge is not stabilized, and hillocks or foreign substances are generated. There is a case. In addition, oxygen in water may remain over a long period of time, causing oxidation of the underlying metal film. As a result, defects, such as peeling and a raise of resistance, arise, and migration may fall conversely.

[Non-Patent Document 1] Owaki et al., `` Preferred Orientation in Ti Films Sputter-Deposited on SiO ₂ Glass: The Role of Water Chemisorption on the Substrate, '' Japanese Journal of Applied Physics, issued February 1, 1997, 36. Vol., P. L154-L157

1 is a schematic diagram showing an apparatus for manufacturing a semiconductor device according to a first embodiment of the present invention.

2 is a schematic diagram illustrating an apparatus for manufacturing a semiconductor device according to a second embodiment of the present invention.

Fig. 3A is a sectional view showing a vaporizer installed in the second embodiment, and Fig. 3B is a sectional view showing the inside of the pipe installed in the vaporizer.

An object of the present invention is to provide a manufacturing apparatus and a manufacturing method of a semiconductor device capable of forming a high melting point metal film with high orientation.

The apparatus for manufacturing a semiconductor device according to the present invention has a film forming chamber and metal film forming means for forming a metal film above the semiconductor substrate in the film forming chamber. The manufacturing apparatus further has a water supply means for containing water in the metal film only at the initial stage in forming the metal film by the metal film forming apparatus.

In the method of manufacturing a semiconductor device according to the present invention, H ₂ O in a gas or fog state is _first supplied to the surface of the semiconductor substrate while maintaining the temperature of the semiconductor substrate at 0 ° C. or lower in the pretreatment chamber. Next, the semiconductor substrate is transferred to the film formation chamber. A metal film is formed above the semiconductor substrate in the film forming chamber.

Best Modes for Carrying Out the Invention Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

(First embodiment)

First, the first embodiment of the present invention will be described. 1 is a schematic diagram showing an apparatus for manufacturing a semiconductor device according to a first embodiment of the present invention.

In this embodiment, the wafer stage 2 on which the wafer is mounted and disposed in the film formation chamber 1 and the target 3 used for sputtering, for example, a Ti target, are provided. In addition, a load lock chamber (not shown) is provided at the front end of the film formation chamber 1.

On the discharge side of the film formation chamber 1, a polymer turbopump 9 and a dry pump 10 are connected in series via a valve. Moreover, the quadrupole mass spectrometer (Q-mass) 4 which measures the water content in the film-forming chamber 1 based on partial pressure is also connected to the film-forming chamber 1 via a valve.

In addition, the supply line (first feeding means) of the Ar gas supply line and the H ₂ O with the addition of pure (純) Ar gas input side of the deposition chamber (1) is connected. Each of these supply lines is provided with a mass flow controller (MFC) 7 and 8.

The quadrupole mass spectrometer 4 controls the flow rate of the gas supplied to the film formation chamber 1 by controlling the amount of opening when the mass flow controllers 7 and 8 are turned on. The flow control device 5 is connected. The addition amount control means is comprised by the flow volume control apparatus 5 and the mass flow controller 8. Moreover, the apparatus control unit 6 which controls ON / OFF of the mass flow controllers 7 and 8 is connected to the flow volume control apparatus 5.

Next, an operation of the manufacturing apparatus of the semiconductor device configured as described above and a method of manufacturing the ferroelectric memory (semiconductor device) using the manufacturing apparatus will be described.

First, semiconductor elements such as control transistors, formation and planarization of interlayer insulating films, contact holes, formation of tungsten (W) plugs, and the like are performed on semiconductor wafers such as silicon wafers.

Next, a Ti film is formed by DC sputtering as a part of the lower electrode film of the ferroelectric capacitor using the above-described apparatus for manufacturing a semiconductor device. Table 1 shows the states of the mass flow controllers 7 and 8 when the Ti film is formed.

time MFC for Pure Ar Gas (7) MFC for Ar gas with H ₂ O (8) Gas stabilization For 3 seconds On On Formation of Ti film For 5 seconds On On For 5-10 seconds off off

When the Ti film is formed, the mass flow controllers 7 and 8 are turned on in order to stabilize the gas in the film formation chamber 1 after the semiconductor wafer is mounted on the wafer stage 2. The operation of turning on the mass flow controllers 7 and 8 is controlled by the device control unit 6.

After 3 seconds have elapsed since the mass flow controllers 7 and 8 are turned on, deposition of the Ti film is actually started. As film-forming conditions at this time, film-forming temperature is made into room temperature, for example, the thickness of a Ti film is set to 20 nm, DC power is 2.06 kV and the flow rate of Ar gas is 100 sccm. In addition, while the amount of opening of the mass flow controller 8 detects the amount of water in the film forming chamber 1 using the quadrupole mass spectrometer 4, the amount of water in the film forming chamber 1 is controlled by the flow rate control device 5. The predetermined value, for example, is controlled to be about 10 to 300 ppm.

Then, 5 seconds after actually starting the film formation of the Ti film, the mass flow controller 8 is turned off by the control by the apparatus control unit 6. That is, the water supply to the film formation chamber 1 is cut off, and only Ar gas is supplied.

When 5 to 10 seconds have elapsed after the mass flow controller 8 is closed, the film formation of the Ti film is finished.

In the film forming process of the series of Ti films, the mass flow controller 8 is turned on and then turned off. For this reason, in the period in which the mass flow controller 8 is turned on, moisture is contained in the sputtering gas and moisture is present in the film formation chamber 1. In addition, the amount of water in the film formation chamber 1 is controlled using the quadrupole mass spectrometer 4 in parallel with this. As a result, the Ti film having a strong C-axis orientation can be stably formed without being influenced by the attained vacuum degree of the film formation chamber 1, the processing lot number, and the like.

In addition, in order to align the orientation of the crystals, it is very important to control the orientation at the beginning of crystal growth, and if a strong orientation is initially obtained, there is no need to supply moisture thereafter. On the contrary, if water is continuously supplied, an oxide is formed in the Ti film, which may raise the resistance. For this reason, in the film-forming process of Ti film mentioned above, water is supplied initially, but after that, the mass flow controller 8 is turned off and water supply is stopped.

After the film formation of the Ti film, a Pt film is formed on the Ti film by DC sputtering as another part of the lower electrode film in a chamber different from the film forming chamber 1. As film-forming conditions at this time, film-forming temperature is 100 degreeC, for example, the thickness of a Pt film is 175 nm, DC power is 1.04 kPa, and the flow volume of Ar gas is 100 sccm. Moisture addition to Ar gas is not performed.

Subsequently, a PZT film is formed on the Pt film by the RF sputtering method as a capacitor film. As film-forming conditions at this time, film-forming temperature is made into room temperature, for example, the thickness of a PZT film is set to 200 nm, RF power is 1.0 kW and the flow rate of Ar gas is set to 15-25 sccm. At this time, the flow rate of Ar gas is appropriately controlled in order to adjust the Pb content in the PZT film. After the PZT film is formed, crystallization annealing is performed.

The PZT film can be formed by a sol-gel method, a MOCVD method, or the like, in addition to the RF sputtering method. In addition, impurities such as Ca, Sr, and La may be introduced into the PZT film, depending on the required capacitor characteristics.

After the formation of the PZT film, an IrO _x film is formed in two steps by the DC sputtering method as the upper electrode film of the ferroelectric capacitor. As the film formation conditions are, for example, and the film forming temperature to 20 ℃, and the IrO _x film thickness in 200㎚. In the first step, the DC power is 1.04 kW, the flow rate of Ar gas is 100 sccm, the flow rate of O ₂ gas is 100 sccm, and the film formation time is 29 seconds. In the second step, the DC power is 2.05 kW, the flow rate of Ar gas is 100 sccm, the flow rate of O ₂ gas is 100 sccm, and the film formation time is 22 seconds.

Thereafter, the IrO _x film, the PZT film, the Pt film, and the Ti film are processed into the shape of the ferroelectric capacitor by photography technique and etching. The ferroelectric memory is completed by forming and planarizing another layer, forming contact holes, and forming wirings.

According to this first embodiment, it is possible to detect the amount of water in the film formation chamber 1 using the quadrupole mass spectrometer 4, and feed this back to control the amount of water. Therefore, stable orientation can be obtained by appropriately controlling the amount of water contributing to the orientation of the Ti film.

As the flow rate control device 5, for example, a general-purpose personal computer provided with a control program can be used.

(Second embodiment)

Next, a second embodiment of the present invention will be described. 2 is a schematic diagram illustrating an apparatus for manufacturing a semiconductor device according to a second embodiment of the present invention. 3A is a cross-sectional view showing the vaporizer provided in the second embodiment, and FIG. 3B is a cross-sectional view showing the inside of the pipe provided in the vaporizer.

In this embodiment, as shown in FIG. 2, a load lock chamber (pretreatment chamber) 12 is connected to a front end of the film formation chamber 11 via a damper or the like. The load lock chamber 12 is connected with a pipe supplied with N ₂ gas and H ₂ O in a gas or fog state. This pipe is connected from the vaporizer (pre-film formation moisture means) 13.

The vaporizer 13 has a water tank (second addition means) 21, a drain pipe 22, and a drain pipe as shown in Figs. 3A and 3B. A pipe 23 is provided. A pipe 24 through which the N ₂ gas flows is disposed directly above the water tank 21. The opening part 25 is formed in the piping 24 in contact with the water surface of the accumulated water in the water tank 21. The pipe 24 is a pipe connected to the load lock chamber 12.

In the vaporizer 13 configured as described above, when N ₂ gas flows into the pipe 24 while water is supplied from the drain pipe 22 to the water tank 21 and the water tank 21 is filled, the water in the water tank 21 evaporates. Thus, water vapor floating on the surface of the water flows in the pipe 24 together with the N ₂ gas.

In the load lock chamber 12, a transfer unit (stage) 15 on which the wafers 20 are mounted and arranged is provided, and outside the load lock chamber 12, the transfer unit 15 is cooled using liquid nitrogen. The cooler 14 is arranged. The temperature of the conveyance part 15 is maintained at 0 degrees C or less, for example -4 degreeC. The conveyance part 15 is provided with a conveyance roller narrower than the wafer 20.

On the other hand, in the film formation chamber 11, the wafer stage 16 in which the wafer 20 is mounted, and the target 17 used for sputtering, for example, the Ti target, are provided. Moreover, the supply line of Ar gas is connected to the input side of the film-forming chamber 11. For example, a negative bias is applied to the target 17.

In addition, although not shown in figure 2, the pump (vacuum means) which reduces the pressure in the film-forming chamber 11 and the load lock chamber 12 to ^10-3 Pa or less is provided.

Next, the operation of the manufacturing apparatus of the semiconductor device configured as described above and the manufacturing method of the ferroelectric memory (semiconductor device) using the manufacturing apparatus will be described.

First, similarly to the first embodiment, the formation of semiconductor elements such as control transistors, formation and planarization of interlayer insulating films, formation of contact holes, formation of tungsten (W) plugs, and the like are performed on semiconductor wafers such as silicon wafers.

Next, a Ti film is formed by DC sputtering as a part of the lower electrode film of the ferroelectric capacitor using the above-described apparatus for manufacturing a semiconductor device.

At the time of forming a Ti film, the semiconductor wafer 18 is first mounted on the transfer section 15 and arranged. And water is supplied from the drain pipe 22 to the water tank 21 by the flow volume of 20 kPa / min, for example. Water overflowing from the water tank 21 is discharged from the drain pipe 23. In addition, the N ₂ gas is allowed to flow through the pipe 24 at a flow rate of 60 sccm. As a result, water vapor (H ₂ O gas) evaporated from the water tank 21 is supplied into the load lock chamber 12 together with the N ₂ gas. In addition, the temperature of the conveyance part 15 is maintained at -4 degreeC in parallel with these, for example.

As a result, in the load lock chamber 12, water vapor supplied from the pipe 24 is liquefied in a mist state. In addition, the temperature of the wafer 18 becomes 0 degrees C or less, and the N ₂ gas containing water is supplied to the surface. For this reason, after a water droplet adheres to the surface of the wafer 18, it solidifies.

Then, the semiconductor wafer 18 is conveyed to the film-forming chamber 11 in the state which cooled the conveyance part 15 continuously.

Then, Ar gas is supplied as the sputtering gas into the film forming chamber 11 to start film formation of the Ti film. Moisture adhered to the surface of the semiconductor wafer 18 and solidified is liquefied in the film forming chamber 11. In this state, since the Ti film starts to deposit, moisture is suitably accommodated in the Ti film. As a result, a Ti film with a strong C-axis orientation is formed. In addition, since water is mainly consumed at the initial stage of film formation of the Ti film, oxidation of Ti hardly occurs in most of the Ti film in the thickness direction. There is also some water evaporating in the deposition chamber 11, but they are absorbed in the Ti film to such an extent that they contribute little to the oxidation of Ti. Therefore, moisture hardly adheres to the jig in the film formation chamber 11, and abnormal discharge caused by this adhesion is prevented.

After the formation of the Ti film, the ferroelectric memory is completed by forming the Pt film, the PZT film, the IrO _x film, and the like as in the first embodiment.

According to this second embodiment, moisture is adhered to the wafer 18 in advance, instead of supplying moisture from the outside during the film formation of the Ti film, thereby preventing moisture from adhering to the jig in the deposition chamber 11. Can be. As a result, it is possible to prevent abnormal discharge. In addition, since moisture can be prevented from remaining for a long period of time, it is possible to avoid unnecessary oxidation and to prevent peeling of the Ti film and an increase in resistance. And since moisture is accommodated at the beginning of film formation of the Ti film, strong C-axis orientation is obtained.

Here, the characteristics of the Ti film formed by actually using the apparatus for manufacturing a semiconductor device according to the second embodiment will be described while comparing with the comparative example.

First, as a sample, a semiconductor wafer with a SiO ₂ film having a thickness of 100 nm was prepared on the surface. Then, a Ti film having a thickness of 100 nm was formed on the semiconductor wafer. At this time, in the embodiment, moisture was deposited on the semiconductor wafer by using the apparatus for manufacturing a semiconductor device according to the second embodiment, but in the comparative example, the baking was performed at 150 ° C. in a load lock chamber without depositing moisture. .

Adhesion was carried out under the following conditions. First, water was supplied to the water tank 21 at the flow volume of 20 kPa / min. In addition, N ₂ gas was caused to flow through the pipe 24 at a flow rate of 60 sccm. And the temperature of the conveyance part 15 was kept at -4 degreeC. The adhesion of moisture was started under such conditions, and the supply of N ₂ gas and water vapor was stopped when the observation window (not shown) provided in the load lock chamber 12 became cloudy. Then, the sample (semiconductor wafer 18) was conveyed to the film-forming chamber 11 in the state which cooled the conveyance part 15 continuously.

After the film formation of the Ti film, crystal orientation in the Ti film was analyzed by X-ray diffraction (XRD). The results are shown in Table 2. As shown in Table 2, according to the Example, strong C-axis orientation was obtained.

Peak intensity (cps) Half-degree C-axis orientation Ti <002> Orientation Orientation Ti <101> C-axis orientation Ti <002> Orientation Orientation Ti <101> Example 708 1502 0.49 0.60 Comparative example 1485 506 0.53 0.43

As the carrier gas in the vaporizer 13, other inert gas such as He gas, Ne gas, or Ar gas may be used instead of the N ₂ gas.

As the refrigerant in the cooler 14, instead of liquid nitrogen, an alternative Freon gas or He gas may be used.

Incidentally, in the first and second embodiments, a Ti film is formed as the metal film, but other high-melting-point metal films such as Ta, W, and Mo may be formed.

It is also possible to combine the first embodiment and the second embodiment. That is, the load lock chamber 12 shown in FIG. 2 etc. can also be provided in front of the film-forming chamber 1 shown in FIG.

In addition, the semiconductor device to be manufactured is not limited to the ferroelectric memory. For example, the present invention can be applied to the manufacture of another semiconductor device having Al wiring.

As described above in detail, according to the present invention, since water is supplied during the film formation of the metal film, a strong C-axis orientation is obtained. In addition, since the water supply can be performed only at the initial stage of film formation while controlling the amount thereof, the variation in the orientation can be suppressed, and the occurrence of abnormal discharge due to the supply more than necessary can be suppressed.

Claims (21)

Film forming chamber, Metal film forming means for forming a metal film above the semiconductor substrate in the film forming chamber; An apparatus for manufacturing a semiconductor device having water supply means for containing water in the metal film only at an initial stage when the metal film is formed by the metal film forming means. The method of claim 1, The metal film forming means, A sputtering target installed in the chamber, And a sputtering gas supply means for supplying a sputtering gas into the chamber. The method of claim 1, And the water supply means has a first addition means for adding H ₂ O gas to the sputtering gas supply means. The method of claim 3, wherein Measuring means for measuring the moisture content in the chamber; An apparatus for manufacturing a semiconductor device having an addition amount control means for controlling the amount of water added by the first adding means based on the content measured by the measuring means. The method of claim 4, wherein The said measuring means is a manufacturing apparatus of the semiconductor device which has a quadrupole mass spectrometer. The method of claim 4, wherein And said addition amount controlling means has a mass flow controller. The method of claim 6, The mass flow controller is a semiconductor device manufacturing apparatus provided in a pipe for supplying a mixed gas of H ₂ O gas and Ar gas to the chamber. The method of claim 2, The said sputtering target is a manufacturing apparatus of the semiconductor device which consists of a high melting point metal. The method of claim 1, A pretreatment chamber connected to the deposition chamber; Having a stage on which the semiconductor substrate is mounted and disposed; The water supply means, Pre-film formation moisture supply means for supplying gas or fog H ₂ O into the pretreatment chamber; The manufacturing apparatus of the semiconductor device which has cooling means which cools the temperature of the said stage to 0 degrees C or less. The method of claim 9, The metal film forming means, A sputtering target installed in the chamber, And a sputtering gas supply means for supplying a sputtering gas into the chamber. The method of claim 9, The film formation moisture supply means, An inert gas flows and is connected to the pretreatment chamber, Apparatus for manufacturing a semiconductor device having a second addition means for adding H ₂ O gas in the pipe. The method of claim 9, The cooling means is a device for manufacturing a semiconductor device that distributes a refrigerant inside the stage. The method of claim 9, An apparatus for manufacturing a semiconductor device, comprising vacuum means for setting the pressure in the film formation chamber and the pretreatment chamber to 10 ⁻³ Pa or less. The method of claim 10, The said sputtering target is a manufacturing apparatus of the semiconductor device which consists of a high melting point metal. The method of claim 10, The stage is an apparatus for manufacturing a semiconductor device having a conveying roller that is narrower in width than the semiconductor substrate. Supplying H ₂ O in a gas or fog state to the surface of the semiconductor substrate while maintaining the temperature of the semiconductor substrate at 0 ° C. or lower in the pretreatment chamber; Conveying the semiconductor substrate to the deposition chamber; A method of manufacturing a semiconductor device, comprising the step of forming a metal film above the semiconductor substrate in the film formation chamber. The method of claim 16, The manufacturing method of a semiconductor device which performs the process of forming the said metal film by sputtering method. The method of claim 17, The manufacturing method of the semiconductor device which uses what consists of high melting point metals as a sputtering target. The method of claim 16, The manufacturing method of the semiconductor device which uses the conveyance roller narrower than the said semiconductor substrate in the process of conveying the said semiconductor substrate. The method of claim 16, The process of conveying the said semiconductor substrate has the process of making the pressure in the said preprocessing chamber and the said film-forming chamber into 10 <^-3> Pa or less. The method of claim 16, The step of supplying H ₂ O to the surface of the semiconductor substrate includes a step of flowing an inert gas into a pipe connected to the pretreatment chamber while adding H ₂ O gas therein.