JPH11162851A - Method and apparatus for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize production of a high quality of thin film by preventing in advance an incident of a defective thin film caused by sputtering a substance other than the material for film formation. SOLUTION: A target surface state discriminating circuit 17 monitors a discharge characteristic (sputter current/voltage characteristic) of a film during sputtering formation of the film, compares the discharge characteristic with a previously acquired target surface state, and discriminates the target surface state and change on a real time basis. A target consumption estimating circuit 19 accurately estimates the target consumptions associated with the respective surface states and calculates a total target consumption. A target consumption limit discriminating circuit 20 compares its estimated result with a predetermined use limit value and adjusts it so as not to exceed the use limit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device and an apparatus for manufacturing a semiconductor, and more particularly to a technique which is effective when applied to the determination of a target life in a sputtering apparatus.

[0002]

2. Description of the Related Art Sputtering is a method for industrially forming a thin film, and has been widely used in recent years for manufacturing microelectronic components. In sputtering, a generally flat plate-like material (raw material) composed of a target thin film material called a sputtering target (hereinafter, referred to as a target) is converted into a low-pressure inert gas atmosphere (usually about several milliTorr. Ar gas), generate a plasma of an inert gas by glow discharge, apply a high negative voltage to the target to accelerate positive ions of the inert gas to collide with the target, and scatter by the impact. In many cases, the target material is deposited on a substrate placed close to the front of the target plate.

Since this sputtering needs to be performed in a low-pressure gas atmosphere, the target is contained in a vacuum vessel. This target will naturally wear out as you use it. In addition, there is a fast-wearing area on the target, which is called an erosion area. When the area is reduced to the thickness of the target plate, the life of the target is extended.

[0004] An accident caused by overuse of the target is that the target is already worn out and sputtering is performed with the backing plate for fixing the target exposed. In this case, the material of the backing plate is mixed into the sputtered film, and a predetermined film cannot be formed.

On the other hand, if the target plate is replaced too early,
Discarding the usable target plate not only results in a disadvantage in cost, but also causes an increase in replacement work and a deterioration in the operation rate.

Therefore, it is important to have a function of appropriately determining the replacement time of the target plate so as not to form the defective film.

[0007] As a method of appropriately determining the target replacement time of this target, for example, Japanese Patent Application Laid-Open No. 8-26 is disclosed.
As disclosed in Japanese Patent No. 0142, the target consumption coefficient is determined according to the component ratio of the introduced gas, which is one of the film forming conditions, and the target consumption coefficient and the power amount during the sputtering are determined. It is known to estimate the consumption of the target based on the following.

[0008]

However, it has been found by the present inventors that the above method for determining the target replacement time in sputtering has the following problems.

This method is for correcting an error caused by estimating the target consumption due to the difference in the target consumption ratio depending on the film formation conditions. It was found that the sensitive factor was the target surface state rather than the component ratio of the mixed gas introduced during sputtering.

In other words, it has been found that the degree of consumption of the target varies greatly depending on the surface condition of the target even when the sputtering is performed with the same component ratio of the mixed gas introduced. In addition, the thickness of the film generated on the film formation target substrate,
Since the change in the composition in the film thickness direction also strongly depends on the change in the surface state of the target, the management of the surface state of the target is important.

As a specific example of the above-mentioned phenomenon, for example, in the case where the target surface is oxidized or nitrided before film formation, the target surface is clean even by ordinary sputtering using only Ar (argon) gas. Even with the same amount of power, the target consumption ratio is clearly different.

The former state of surface oxidation is a phenomenon that cannot be avoided due to vacuum breakage caused by periodic replacement of the inside of the vacuum chamber, and the latter state of surface nitridation will be described later with reference to reactivity using N ₂ (nitrogen) gas. This is a phenomenon caused by sputtering.

In order to remove the oxide film and the like and expose a clean surface, an empty deposit using a dummy wafer is performed before entering a normal production deposit. This may cause an error between the estimated consumption amount and the actual consumption amount.

On the other hand, in terms of film quality management, the criterion for determining the number of empty deposits is to evaluate the film quality of the QC wafer after empty deposition and to determine whether the result is within the control value. It was poor.

Further, when a laminated film is formed by alternately using a normal sputtering of only Ar and a reactive sputtering in which a reaction gas is mixed, or by changing the component ratio, a typical example is to alternately use Ti and TiN. In such a case, the surface state of the target does not change immediately when the gas component ratio is switched, and the reaction layer is formed until the equilibrium state is reached or the reaction layer is sputtered and disappears. Delay time.

For this reason, there is a problem that the error in the estimated value is large because the change in the consumption rate of the target changes starting from the time when the change in the surface state of the target occurs.

An object of the present invention is to prevent a defective thin film from being formed due to spattering of a substance other than a material to be formed, thereby realizing production of a thin film having stable quality for a long time. An object of the present invention is to provide a semiconductor device manufacturing method and a semiconductor manufacturing apparatus.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0019]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, in the method of manufacturing a semiconductor device according to the present invention, the sputtering conditions including the sputtering voltage during sputtering, the sputtering current, the gas pressure in the film formation chamber, and the flow ratio of the sputtering gas introduced into the film formation chamber are monitored. A step of determining a surface state of a target made of a material to be formed during sputtering and a change in the change thereof based on the monitored sputtering conditions, and a step of determining the determined result, the monitored sputtering voltage and the sputtering. A step of selecting an appropriate consumption coefficient corresponding to the current based on a list of power consumption per unit electric power, which is a target consumption coefficient obtained in advance by measurement for each surface state of the target; Estimating the consumption of the target in time according to the target consumption coefficient, and estimating the total consumption of the target; A step of comparing the predetermined consumption limit value previously stored with the results estimated by the, and a step to stop the sputtering when the comparison result exceeds the consumption limit.

Further, the method of manufacturing a semiconductor device according to the present invention
The sputtering gas is composed of at least two types of a carrier gas and an active gas.

Further, in the method of manufacturing a semiconductor device according to the present invention, the carrier gas is Ar, the active gas is N ₂ , and the target material is Ti.

Further, the semiconductor manufacturing apparatus of the present invention comprises a voltage measuring means for measuring a sputtering voltage during sputtering, a current measuring means for measuring a sputtering current during sputtering, and a gas pressure in a film forming chamber during sputtering. Gas pressure measuring means
Flow rate control means for controlling a flow rate ratio of a sputter gas introduced into a film forming chamber during sputtering, a sputter voltage measured by the voltage measurement means, a sputter current measured by the current measurement means, and a gas pressure measurement Based on the sputtering conditions comprising information on the gas pressure measured by the means and the gas flow ratio controlled by the flow ratio control means, during sputtering, the surface state of the target made of the material to be deposited and its change Target surface state determining means for determining transition, target consumption estimating means for estimating the total consumption of the target based on the result determined by the target surface state determining means, and target consumption estimating means. The result is compared with a predetermined consumption limit value stored in advance, and when the consumption limit is exceeded, a predetermined signal is output. Is obtained by a more becomes the target monitoring means with the target consumption limit judging means for outputting.

Further, in the semiconductor manufacturing apparatus according to the present invention, the target monitoring means determines whether or not the surface state of the target is a desired surface state based on the determination result of the target surface state determination means. A warning means is provided for giving a warning when the surface condition of the target is not the desired surface condition.

Further, in the semiconductor manufacturing apparatus according to the present invention, the target consumption estimating means stores a target consumption coefficient which is a list of consumption per unit electric power obtained by measurement in advance for each surface state of the target. And a target consumption coefficient stored in the target consumption coefficient storage unit corresponding to the target surface state information input from the target consumption coefficient storage unit and the sputtering condition and the target surface state determination unit. A target consumption coefficient selecting section for selecting the target consumption coefficient, and a target consumption calculating section for temporally integrating the target consumption according to the target consumption coefficient selected by the target consumption coefficient selecting section and temporally integrating the target consumption. It consists of

Further, in the semiconductor manufacturing apparatus according to the present invention, the target monitoring means is provided with a spatter preventing means for preventing erosion of the target based on a predetermined signal output from the target consumption limit determining means.

Further, in the semiconductor manufacturing apparatus according to the present invention, the spatter preventing means comprises interlock means for stopping a sputter power supply for applying a voltage to a sputter electrode based on a predetermined signal from a target consumption limit judging means. is there.

As described above, the surface state of the target and its change can be determined during the film formation, and the life of the target can be estimated with high accuracy based on the determination. It is possible to prevent an accident of forming a defective thin film due to sputtering.

Further, since the target can be exchanged at an optimum time, stable thin film production can be realized for a long period of time, and the quality of a semiconductor device as a product can be greatly improved.

[0030]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of a sputtering apparatus according to one embodiment of the present invention, FIG. 2 is an explanatory diagram for judging the surface condition of a target according to one embodiment of the present invention, and FIG. FIG. 4 is an explanatory diagram of target consumption estimation in normal sputtering according to an embodiment of the present invention, and FIG. 4B is an explanatory diagram of target consumption estimation in reactive sputtering.

In this embodiment, a sputtering apparatus (semiconductor manufacturing apparatus) 1 in which film formation of Ti (titanium) film by ordinary sputtering and film formation of TiN (titanium nitride) by reactive sputtering are performed in combination. Is
A chamber (film forming chamber) 2 is provided as a reaction chamber for keeping the vacuum atmosphere while shielding the outside air during the film forming.

The sputtering apparatus 1 is provided with a cylindrical cathode 3 at an upper part in the chamber 2.
A semiconductor wafer W to be formed is formed in a lower portion of the chamber 2.
Is provided, and the cathode 3 and the substrate holder 4 form a sputter electrode. Below the cathode 3, there is provided a magnetic field generator 5 composed of N-pole and S-pole magnets for generating a rotating magnetic field.

Further, below the magnetic field generating unit 5, a backing plate 6, which is a target holding plate described later, is provided. The surface of the backing plate 6 is made of a film forming material so as to face the semiconductor wafer W. A target 7 made of Ti is attached to the cathode 3 after being fixed by, for example, metal bonding. The target 7 is cooled by cooling the surface of the backing plate 6 opposite to the surface on which the target 7 is fixed with a cooling medium such as water.

Next, an introduction pipe 8 for supplying Ar gas (carrier gas) and an introduction pipe 9 for supplying N ₂ gas (active gas) are provided below the chamber 2.
The mixed gas is introduced through these introduction pipes 8 and 9.

Gas flow controllers 10 and 11 for controlling the flow rates of the respective gases and flow ratio controllers (flow ratio control means) 12 for adjusting the flow ratio of the gases are provided in the introduction pipes 8 and 9. Is provided.

Further, an exhaust pipe 13 for exhausting the inside of the chamber 2 is provided below the chamber 2, and one end of the exhaust pipe 13 is connected to a vacuum pump, and is connected to the vacuum pump. A predetermined atmosphere is maintained during the sputtering by the exhaust pipe 13 thus formed.

Next, the sputtering apparatus 1 is provided with a sputtering power supply 14 for generating a high direct current (DC) voltage for applying a negative potential of about -300 V to -2000 V to the target 7, for example.

The sputtering apparatus 1 has a voltmeter (voltage measuring means) 15, an ammeter (current measuring means) 16, and these voltages for monitoring the voltage and current supplied from the sputtering power supply 14 to the target 7 in real time. A target surface state determination circuit (target surface state determination means) 17 to which a sputter voltage and a sputter current during film formation measured by the meter 15 and the ammeter 16 are input in real time is provided.

Further, on the side of the chamber 2 of the sputtering apparatus 1, a gas pressure gauge (gas pressure measuring means) 18 for measuring the gas pressure in the chamber 2 is provided. The gas pressure gauge 18 is provided in the target surface state determination circuit 17.
The measurement result of the target and the information on the gas flow ratio in the gas flow ratio controller 12 are used in real time to determine the target surface condition.
7 has been entered.

Then, the target surface state determination circuit 17
Stores sputter current-voltage characteristics corresponding to various target surface states obtained in advance by measurement, and stores these data and the sputter current during film formation described above.
By comparing the voltage characteristics, the surface state of the target 7 can be determined.

Here, the target surface state determination circuit 17
Will be described.

The target surface state determination circuit 17 utilizes the fact that the discharge characteristics are sensitive to the target surface state in order to know in real time a change in the target surface state during film formation. Since the secondary electron emission coefficient strongly depends on the surface state of the target, a property that the discharge state of the plasma is different even at the same applied voltage or the same applied power is used.

That is, when a target surface on which an oxide film is sufficiently formed after opening to the atmosphere or a reactive sputtering is used together, for example, a target surface which is nitrided by reactive sputtering with N ₂ (this is a reaction surface). Voltage, sputter current, gas pressure in the chamber 2 during sputtering used in production depots in each state of the clean target surface after formation of a vacant sputter (deposited by reactive sputter) and after a normal empty depot has been sufficiently performed. In addition, discharge characteristic data (for example, sputtering current-sputtering voltage characteristic) under normal sputtering conditions and reactive sputtering conditions (for example, Ar gas pressure, input power, and the like) including a flow ratio of a sputtering gas, are measured in advance. By comparing the data with the discharge characteristics at the production depot, the target surface can be cleaned. It can be determined whether the or another state or a surface.

In particular, the discharge characteristics during the period from discharge ignition until the discharge is stabilized characteristically show the target surface state. Further, even if the discharge is stable, the change in the target surface state appears as a change in the sputter voltage or the sputter current under constant power control. Similarly, in the case of constant voltage control, it appears as a change in sputter current or sputter power.

As described above, by monitoring the transition of the discharge characteristic parameter during sputtering and comparing it with the discharge characteristic of each target surface state acquired in advance, it is possible to know the target surface state and its change in real time. Becomes possible.

Next, the sputtering apparatus 1 is provided with a target consumption estimating circuit (target consumption estimating means) 19 for estimating the consumption of the target 7.

Further, the target consumption estimating circuit 19
Is a target consumption coefficient storage unit 19 that stores a list of target consumption coefficients (consumption per unit power) obtained in advance for each surface state of the target 7.
a, an appropriate consumption coefficient is selected based on the target consumption coefficient list stored in the target consumption coefficient storage unit 19a in accordance with the film formation conditions and the surface state information of the target 7 input from the target surface state determination circuit 17. The target consumption amount is temporally integrated according to the target consumption coefficient selection unit 19b and the consumption coefficient, and the consumption coefficient is reselected when the change of the surface state is input, whereby the target consumption amount is temporally reduced. It comprises a target consumption calculator 19c for integrating.

The result of the judgment by the target surface condition judging circuit 17 is inputted to a target consumption coefficient selecting section 19b.
Sputtering voltage during film formation measured by the ammeter 16;
The sputter current is input in real time.

Here, the target consumption estimating circuit 19 will be described.

First, the degree of consumption of the target surface in each state may be determined, for example, per unit area of atoms constituting a target material in a film formed on a target substrate such as a semiconductor wafer per unit time in advance. It is converted based on the number of atoms (which can be measured by X-ray fluorescence or the like).

Therefore, it is necessary to compare this value with the amount actually consumed per unit time (the thickness change of the target) at least once. If this value is converted per unit input power (value per unit power), and the target consumption coefficient in each surface state is calculated, the total target consumption in each surface state is equal to the sputtering The total consumption of the target is calculated as the sum of the total consumption in each surface state, which is calculated by the product of the deposition time, the input power, and the consumption coefficient of the surface.

Next, the sputtering apparatus 1 includes a target power limit determining circuit (target power limit determining means) 20 for determining a target power limit and a sputtering power source based on a control signal input from the target power limit determining circuit 20. An interlock circuit (sputter prevention means, interlock means) 21 for stopping the sputtering by stopping the operation is provided.

The target consumption limit determination circuit 20 receives the target consumption estimation value estimated by the target consumption estimation circuit 19.

Then, the target consumption limit determination circuit 20
Compares the target consumption limit value optimally determined in advance with the target consumption estimation value, and if the consumption limit value is exceeded, immediately sends a control signal indicating that fact to the interlock circuit 21. input. As a result, the interlock circuit 21 performs a protection operation such as stopping the power supply.

Further, in order to control the film quality of the laminated film based on the judgment result of the target surface state judgment circuit 17, if the target surface state cannot obtain a desired thin film, the sputtering apparatus 1 Interlock circuit (warning means) to prevent film formation
22 are provided.

For example, when the surface state of the target 7 is not in a state where a desired film can be formed, a warning lamp is turned on, and the surface state of the target 7 becomes a state in which a desired film can be formed. In such a case, the operator is notified by turning off a warning light or the like, or the surface of the semiconductor wafer is covered with a shutter or the like, and the shutter is not opened until the surface state of the target 7 becomes a state where a desired film can be formed. It is.

The flow ratio controller 12, voltmeter 15, ammeter 16, target surface state determination circuit 17,
The gas pressure gauge 18, the target consumption estimating circuit 19, the target consumption limit judging circuit 20, the interlock circuit 21, and the interlock circuit 22 constitute a target monitoring means TM.

Next, a method of forming a film on the semiconductor wafer W will be described.

First, the semiconductor wafer W is placed on the substrate holder 4, Ar gas is introduced into the chamber 2 evacuated to form a Ti film, and a high DC voltage is applied by the sputtering power supply 14. Generates plasma.

Here, the TiN film is formed on the surface of the semiconductor wafer W after the Ti film is formed. In this case, the surface of the target 7 has a T
After the TiN on the surface of the target 7 is sputtered, the surface of the target 7 becomes Ti, and a Ti film is formed.

When the TiN film is formed, the surface state of the target 7 does not change at the same time when the composition ratio of the N ₂ gas or the like is switched, and the Ti film is formed after the TiN is sputtered until reaching the equilibrium state. become.

Further, the sputtering voltage generated at this time,
The sputter current is measured by the voltmeter 15 and the ammeter 16, respectively, and is input to the target surface state determination circuit 17 and the target consumption calculator 19c.

Then, the target surface state determination circuit 17
Determines whether the surface state of the target 7 during sputtering is Ti or TiN based on the information of the input sputter voltage, sputter current, gas pressure and gas flow ratio.

Here, the target surface state determination circuit 17
The surface state determination method will be described with reference to FIG.

First, in FIG. 2, curves C1, C2, C
3 and C4 show sputter current-voltage characteristics for each target surface state under two kinds of film forming conditions.

Curves C1 and C2 show examples of sputter current-voltage characteristics when the target surface is Ti and TiN under film forming conditions A (Ar gas pressure) for normal sputtering. Curves C3 and C4 show examples of sputter current-voltage characteristics when the target surface is Ti and TiN under the reactive sputtering condition B (total gas pressure, gas flow ratio).

Each target surface state has sputter current-voltage characteristics corresponding to such film formation conditions, and current and voltage information input from the voltmeter 15 and the ammeter 16 are plotted on this graph. Thus, the target state at that time can be immediately determined.

That is, if the point determined by the voltage and current values input at a certain point during the sputtering under the film forming condition A is near the curve C1, the target surface state is Ti,
If it is near the curve C2, it can be determined that the target surface state is TiN.

If a point (hereinafter referred to as a state point) determined by a voltage and a current value input at a certain point during sputtering under the film forming condition B is near the curve C3, the target surface state is Ti. If it is near the curve C4, the target surface state can be determined to be TiN, and a change in the target surface state can be determined by moving the state point.

For example, when a voltage is applied at a constant voltage of 500 V, if the surface state of the target 7 (FIG. 1) is TiN before the film formation, the state point of the target 7 (FIG.
Follow 1 and reach point a. After that, the surface condition becomes TiN
Can be known by the state point following the process K1.

In the case where sufficient time is required to reach the set voltage, the state point may show a behavior approaching the curve C2 without reaching the point a. Finally, it can be determined that the target surface has become Ti by reaching the point b. When only the constant voltage control is performed, the target surface state can be determined by monitoring the sputtering current after reaching the set voltage.

In the case of constant power control, it is possible to determine that the state has changed to Ti by following the process K2 and finally reaching the point c. In this case, after reaching the set power, the target surface state can be determined by monitoring the voltage or the current.

Further, the case where the reactive sputtering is performed can be similarly determined. That is, if the surface state is Ti, the film formation condition B follows the curve C4 simultaneously with the start of film formation, and the state point changes to the curve C3 when the surface state changes to TiN. Eventually, it can be determined that TiN has been changed to point e in the case of the constant power control of 500 V and to point f in the case of the constant power control of 8 kW.

As described above, the surface state of the target 7 can be determined based on the coordinates of the state point.

Since the change time of the target surface state is very short, it is considered that the target consumption in this process is small. Therefore, as information to be passed from the target surface state determination circuit 15 to the target consumption estimation circuit 16, coordinates that can be taken by the state point are set to Ti, Ti within an appropriate range.
N or TiN
It is considered sufficient as street.

Then, the target surface state determination circuit 17
The determination of the surface state of the target 7 determined by
The sputter voltage and the sputter current during the film formation are input in real time to the target consumption calculator 19c as described above.

The target consumption estimating circuit 19 determines whether the target surface 7 is Ti or not based on these data.
Calculation of the integrated consumption of the target 7 in the case of iN is performed.

Here, a method of estimating the consumption of the target consumption estimating circuit 19 will be described.

First, FIG. 3A shows a sputter power profile during normal sputtering in the constant power mode when the target surface state was TiN before the start of film formation. This corresponds to the process K2 in FIG. Before the change in the sputtering voltage occurs, the surface of the target 7 is TiN. Therefore, the consumption coefficient is determined by multiplying the consumption coefficient corresponding to TiN by time integration up to t1 to obtain a target when the target surface is TiN. The consumption is calculated.

After the sputtering power is changed, the target surface is Ti, so that the consumption coefficient can be calculated by multiplying the power and t2 by using the consumption coefficient corresponding to Ti. .

FIG. 3B shows a sputter current profile during the reactive sputtering in the constant voltage mode when the surface state of the target 7 was Ti before the start of film formation. This corresponds to step K3 in FIG.

Similarly, the target consumption by this process can be estimated by properly using the consumption coefficients of Ti and TiN before and after the change of the current. The target consumption in each process is calculated by such a method, and the total target consumption is sequentially obtained.

The total target consumption calculated by the target consumption estimating circuit 19 is output to the target consumption limit determining circuit 20. The target consumption limit determination circuit 20 compares the target consumption limit value previously determined optimally with the input target total consumption as described above, and exceeds the preset consumption limit value. If so, a control signal indicating that fact is output to the interlock circuit 21 immediately.

When a predetermined control signal is input,
The interlock circuit 21 performs a protection operation such as stopping the power supply, and stops the sputtering.

Thus, according to the present embodiment, the target consumption estimating circuit 19 of the target monitoring means TM can accurately detect the target 7 even when both normal Ti sputtering and TiN reactive sputtering are used.
And the optimal replacement time of the target 7 is determined, so that defective film formation due to excessive use of the target 7 can be reliably prevented, the quality of the semiconductor device as a product is improved, and the film formation cost is significantly reduced. Can be reduced.

In the present embodiment, the case where both the normal Ti sputtering and the TiN reactive sputtering are used is described. For example, even when only the reactive sputtering of TiN is performed, the above-described target monitoring means can be used. By providing the target, the consumption amount of the target can be estimated with high accuracy.

Even when only this reactive sputtering is performed,
The sputtering apparatus 1 has the same configuration as in FIG.

In the sputtering apparatus 1 that performs only reactive sputtering, the target 7 is nitrided on the surface of the target 7 by a nitride such as titanium nitride. And periodically clean the surface of the target 7.

Therefore, even when reactive sputtering of TiN is used in combination with the empty deposition for periodically cleaning the surface of the target 7 by the target monitoring means TM of the sputtering apparatus 1, the consumption of the target 7 can be accurately determined. By estimating and determining the optimal replacement time of the target 7, defective film formation due to excessive use of the target 7 can be reliably prevented, the quality of the semiconductor device as a product is improved, and the film formation cost is significantly reduced. Can be.

The above-mentioned empty deposition needs to be performed even when the surface of the target 7 is oxidized due to replacement of the target 7 or the like.
A target surface state determination function that turns on the warning lamp when the surface of the target 7 is oxidized in the empty depot and turns off the warning lamp when the surface of the target 7 is no longer oxidized. May be used.

Although the invention made by the inventor has been specifically described based on the embodiments of the present invention, the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the scope of the invention. Needless to say, it can be changed.

For example, in the above-described embodiment, the case where the Ti ordinary sputtering and the TiN reactive sputtering are used together has been described. However, this application can be applied to other materials. Further, not only the DC sputtering described in the above embodiment, but also RF (high frequency) sputtering can be applied.

In the present embodiment, the discharge characteristics are used for the determination of the target surface state. However, other means, such as plasma spectroscopy, may be used as a means for determining this.

[0095]

Advantageous effects obtained by typical ones of the inventions disclosed by the present application will be briefly described as follows.
It is as follows.

(1) According to the present invention, the surface condition of the target and its change transition are determined during film formation, and the target life is estimated with high accuracy based on the determination, so that human errors or equipment errors are caused. This prevents the formation of a defective film due to misuse of the target due to a malfunction of the device, and prevents the occurrence of a defective thin film due to spattering of a substance other than the material to be formed.

(2) In the present invention, the target can be replaced at an optimum time, so that the operation rate of the semiconductor manufacturing apparatus can be greatly improved, and the production efficiency and the yield can be improved.

(3) Furthermore, the target monitoring means can judge the surface condition of the sputter target and its change during the film formation and estimate the target life based on the judgment with high accuracy. Therefore, it is possible to prevent an accident of forming a defective thin film due to sputtering of a substance other than the material to be formed.

(4) According to the present invention, (1)
According to (3), stable thin film production can be realized for a long time, and the quality of a semiconductor device as a product can be greatly improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a sputtering apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram for judging a surface condition of a target according to an embodiment of the present invention.

FIG. 3A is an explanatory diagram of target consumption estimation in normal sputtering according to an embodiment of the present invention, and FIG.
FIG. 4 is an explanatory diagram of target consumption estimation in reactive sputtering.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sputtering apparatus (semiconductor manufacturing apparatus) 2 Chamber (deposition chamber) 3 Cathode 4 Substrate holder 5 Magnetic field generation part 6 Backing plate 7 Target 8,9 Introducing piping 10,11 Gas flow controller 12 Flow ratio controller (Flow ratio control Means 13 Exhaust pipe 14 Sputter power supply 15 Voltmeter (Voltage measuring means) 16 Ammeter (Current measuring means) 17 Target surface state determination circuit (Target surface state determining means) 18 Gas pressure gauge (Gas pressure measuring means) 19 Target consumption Estimation circuit (target consumption estimation means) 19a Target consumption coefficient storage section 19b Target consumption coefficient selection section 19c Target consumption calculation section 20 Target consumption limit judgment circuit (target consumption limit judgment means) 21 Interlock circuit (spatter prevention means, inter Locking means) 22 a. Turlock circuit (warning means) TM target monitoring means W semiconductor wafer

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hideshi Kobayashi 5-20-1, Josuihoncho, Kodaira-shi, Tokyo In the semiconductor division of Hitachi, Ltd.

Claims (8)

[Claims] A step of monitoring sputtering conditions including a sputtering voltage during sputtering, a sputtering current, a gas pressure in a film forming chamber, and a flow ratio of a sputtering gas introduced into the film forming chamber, and based on the monitored sputtering conditions. Determining the surface state of the target made of the material to be formed during sputtering and the transition of the change, and an appropriate consumption coefficient corresponding to the determined result and the monitored sputtering voltage and sputtering current. Sorting based on a target consumption coefficient per unit power consumption list, which is a target consumption coefficient obtained in advance by measurement for each surface state of the target, and the target consumption coefficient according to the selected target consumption coefficient. Estimating the total consumption of the target in time, and calculating the estimated result and a location stored in advance. The method of manufacturing a semiconductor device which consumes a limit value and comparing the, characterized in that a step to stop the sputtering when the comparison result exceeds the consumption limit of. 2. The method of manufacturing a semiconductor device according to claim 1, wherein said sputtering gas is composed of at least two kinds of a carrier gas and an active gas. 3. The method of manufacturing a semiconductor device according to claim 2, wherein said carrier gas is Ar and said active gas is N _2.
Wherein the material of the target is Ti. 4. A voltage measuring means for measuring a sputtering voltage during sputtering; a current measuring means for measuring a sputtering current during sputtering; a gas pressure measuring means for measuring a gas pressure in a film forming chamber during sputtering; Flow rate control means for controlling a flow rate of a sputter gas introduced into a film forming chamber inside; a sputter voltage measured by the voltage measurement means; a sputter current measured by the current measurement means; and a gas pressure measurement means. Based on the gas pressure measured by the above and the sputtering conditions consisting of the information of the gas flow ratio controlled by the flow ratio control means, the surface state of the target made of the material to be formed during the sputtering and the transition of the change are shown. Determining the target surface condition based on a result determined by the target surface condition determining device; Target consumption estimating means for estimating the total consumption of the unit, and comparing the result estimated by the target consumption estimating means with a predetermined consumption limit value stored in advance. A semiconductor manufacturing apparatus comprising: a target consumption limit determining unit that outputs a predetermined signal; and a target monitoring unit that includes a target consumption limit determining unit. 5. The semiconductor manufacturing apparatus according to claim 4, wherein the target monitoring means determines whether or not the surface state of the target is a desired surface state based on the determination result of the target surface state determination means. And a warning unit for issuing a warning when the surface condition of the target is not a desired surface condition. 6. The semiconductor manufacturing apparatus according to claim 4, wherein said target consumption estimating means is a list of consumption per unit electric energy obtained by measurement in advance for each surface state of said target. A target consumption coefficient storage unit in which a target consumption coefficient is stored, and an appropriate target consumption coefficient corresponding to the sputtering condition and the target surface state information input from the target surface state determination unit. A target consumption coefficient selection unit for selecting based on the stored target consumption coefficient, a target consumption amount is temporally integrated according to the target consumption coefficient selected by the target consumption coefficient selection unit, and the consumption amount of the target is reduced by time. And a target consumption calculation unit that performs a cumulative integration. Semiconductor manufacturing equipment. 7. The semiconductor manufacturing apparatus according to claim 4, wherein said target monitoring means erodes said target based on a predetermined signal output from said target consumption limit determining means. A semiconductor manufacturing apparatus provided with a spatter preventing means for preventing spatter. 8. A semiconductor manufacturing apparatus according to claim 7, wherein said spatter preventing means is interlock means for stopping a sputter power supply for applying a voltage to a sputter electrode based on a predetermined signal from said target consumption limit judging means. A semiconductor manufacturing apparatus characterized in that: