JP2002110568A - Method of controlling wafer process and processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of controlling a wafer process and a processor used therefor which can detect a failure in a process in situ during processing and immediately feed it back. SOLUTION: When a gas is introduced into a chamber 1 to react the gas therein, thereby treating a wafer surface (not shown) disposed in the chamber 1, a mass analyzer (QMS) 2 is mounted in the chamber 1 to measure the change of a specified element in the chamber 1 by the analyzer 2, thereby controlling the condition of the process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for managing a process of forming a film on a wafer surface or performing an etching process in a semiconductor device manufacturing process or the like, and a process apparatus used therefor. More specifically, the present invention relates to a wafer process management method capable of performing a process while monitoring a process status on the spot while performing a process in a chamber, and a process apparatus used therefor.

[0002]

2. Description of the Related Art Conventionally, in order to check whether or not processes such as a film forming process and an etching process in a semiconductor device manufacturing process are performed according to design values, a monitor portion is provided in a wafer or a lot unit is used. Perform a series of processes using a test wafer separately from the original product wafer,
After a series of processes are completed, a monitor portion and a test wafer are disassembled to check whether a predetermined process is being performed.

[0003]

However, in recent semiconductor devices, the process control has become extremely complicated along with the miniaturization and high integration of circuits, and severe conditions have been required. The possibility of variation is increasing. Furthermore, with complicated processes and high integration,
If the cost per chip becomes high and the feedback on the abnormality that occurs in the manufacturing apparatus or the like is delayed, there is a problem that the loss becomes very large and the cost increases.

[0004] The present invention has been made to solve such a problem, and it is possible to use a method in which a process is performed.
It is an object of the present invention to provide a method of managing a wafer process, which can detect an abnormality in a process and can immediately provide feedback, and a process apparatus used for the method.

[0005]

The inventor of the present invention has proposed a method of introducing a gas into a chamber such as plasma etching or plasma CVD to carry out a process such as silane (Si).
H ₄₎ and oxygen (O ₂₎ silicon oxide film by introducing a gas (U
When forming a SGG film, a mass spectrometer is connected to the chamber to detect and integrate H ₂ ⁺ , which is a residual ion after the reaction, to know the thickness of the formed USG film. It was found that the progress of the process could be accurately known in real time based on the reaction amount.

A method of managing a wafer process according to the present invention is directed to a wafer process for introducing a gas into a chamber and causing the gas to react in the chamber to process a surface of a wafer provided in the chamber. A management method, wherein a mass analyzer is attached to the chamber, and the state of the process is managed by measuring a change of a specific element in the chamber by the mass analyzer.

Here, the term "processing" means a process of introducing a gas such as plasma etching, plasma CVD, or thermal CVD into a chamber to form a film or perform etching.

By using this method, it is possible to detect a substance remaining after the reaction or a substance generated by the etching. Therefore, by calculating the integral value, the amount of the film formed by the reaction on the wafer can be detected. Also, the amount removed by the etching can be accurately known, and the accurate processing amount can be detected. Or, instead of the integral,
By monitoring and detecting a change in signal intensity, it is possible to determine the end point of the etching process. In addition, since the amount can be accurately known while performing the process, if an abnormality occurs in the process, etc., it can be fed back on the spot without a time lag, and the accurate process can be performed without producing defective products. Can be continued.

[0009] By integrating the ion current of the specific element by the mass spectrometer, it is possible to know an accurate reaction amount, it is possible to know the completion time of a predetermined amount of the process, and to determine the end of the process. It is possible to process the film thickness and the etching amount with a very accurate amount.

The process apparatus according to the present invention comprises a process chamber for introducing a gas and causing a reaction inside, and a mass analyzer for introducing a part of the gas in the process chamber. The structure is such that the state of the reaction in the process chamber can be detected.

The process chamber has a plurality of chambers, the mass analyzer comprises one, and each of the plurality of chambers is connected to the mass analyzer via a valve. By adopting a structure in which each process in the plurality of chambers can be monitored by the operation, the entire series of processing steps can be accurately monitored only by providing one mass analyzer in the series of processes.

[0012]

Next, a description will be given of a method of managing a wafer process according to the present invention and a processing apparatus used therein. In the method for managing a wafer process according to the present invention, a gas is introduced into a chamber 1 as shown in FIG. 1 showing an embodiment of a process apparatus for performing the method according to the present invention. When processing a wafer surface (not shown) provided in the chamber 1 by reacting a gas, a mass analyzer (QMS) 2 is attached to the chamber 1 and the inside of the chamber 1 is specified by the mass analyzer 2. The process state is managed by measuring a change in an element.

FIG. 1 shows an example of a cluster in which three chambers 1 for performing a process are provided, and an example in which a mass analyzer 2 is connected to each of the chambers 1 is shown. The mass analyzer 2 is connected to an exhaust line 3 of each chamber 1, and each exhaust line 3 is connected to the chamber 1 via a valve 4.
It is connected to the. In FIG. 1, reference numeral 5 denotes a transfer chamber, which is an apparatus for sequentially loading and unloading wafers loaded from a loader 6 into and out of each process chamber 1. For example, a wafer is set in the first chamber 1 to deposit SiO _2, and The wafer can be taken out from the first chamber 1, the wafer can be set in the second chamber 1 and then etched, for example. It is transported to the unloader 7 and sent from the unloader 7 to the next step.

As the mass analyzer 2, for example, a quadrupole mass analyzer or a magnetic field deflection type mass analyzer is suitable.
The quadrupole mass spectrometer includes, for example, four electrode rods 21 to 24 and an ion detector 26 provided on the outlet side as shown in a schematic diagram in FIG. 2, and a pair arranged in the x-axis direction. A DC voltage and a high-frequency voltage are applied in a superimposed manner between the electrode rods 22 and 24 and a pair of electrode rods 21 and 23 arranged in the y-axis direction, and ions are quadrupled along the z-axis. When incident on the center of the pole, only ions of a specific mass determined by the voltage and the high-frequency voltage can stably pass through the quadrupole, and ions 25 of other masses diverge on the way, thereby causing a specific It detects only mass ions. The mass passing through the quadrupole can be scanned in order from light to heavy.

In the apparatus having such a structure, for example, when the chamber 1 is a chamber for performing a PECVD process, and the SiH ₄ /
When a USG film is formed by introducing O ₂ gas, the intensity of H ₂ ⁺ ion, which is a reaction product, is monitored using a quadrupole mass analyzer 2. FIG. 3 shows the relationship between the value obtained by integrating the H ₂ ⁺ ion intensity and the actually measured thickness of the USG film at that value. As shown in FIG. 3, the thickness of the USG film is substantially proportional to the integral value of the H ₂ ⁺ ion intensity.
By monitoring an integral value of ₂ ⁺ ionic strength, USG
The thickness of the film can be known, the film formation speed can be controlled in situ, and the film thickness can be monitored in real time. As a result, a change in the film thickness due to a change over time in the film forming speed can be corrected by changing the film forming time. Alternatively, an abnormality related to film formation can be quickly detected, and the response can be made. When the ion intensity and the film forming speed are not completely proportional to each other, the film thickness can be monitored by converting the ion intensity into the film forming speed every minute time and integrating over time.

Further, SiH_Four/ PH_Three/ O_TwoIntroduce gas
Therefore, when forming a PSG film, a quadrupole mass analyzer 2 is used.
The reaction product PH_Three ⁺Measuring ionic strength
Can control the concentration of phosphorus (P) in the PSG film
it can. This PH_Three ⁺The value obtained by integrating the ionic strength,
The relationship between the measured value and the P concentration in the PSG film at that value is shown below.
As shown in FIG. As shown in FIG. 4, the P concentration in the PSG film was
The degree (au) is PH _Three ⁺Almost constant with integral value of ion intensity
And if this relationship is checked in advance, PH_Three ⁺I
By monitoring the integrated value of the ON intensity, the PSG film
P concentration can be known and film quality can be controlled in situ.
Can be.

In the above-mentioned example, the P concentration in the PSG film was controlled. Similarly, when forming the BSG film or the BPSG film, the BSG film or the BPSG film was measured by measuring the BH ₃ ⁺ ion intensity. The concentration of boron (B) in the film can be controlled.

This method is not limited to the above examples, and can be similarly used for forming a polysilicon film, a metal thin film or the like by a plasma CVD method, a thermal CVD method, or the like, a plasma etching process, and the like. In
Can be managed in situ.

In the example shown in FIG. 1, the mass analyzer 2 is attached to each process chamber.
Is an example in which one mass analyzer 2 is attached to a plurality of chambers of a cluster. That is, after passing through the valve 4 of the exhaust line 3 connected to each chamber 1, it is connected to one exhaust line 8, and the mass analyzer 2 is attached to the exhaust line 8. With this structure, by sequentially controlling the valves 4, it is possible to detect the reaction products in each of the chambers 1 and to sequentially detect and manage the ions in each chamber. With this structure, it is only necessary to attach one mass spectrometer to one cluster having a plurality of process chambers, and the cost can be reduced.

[0020]

According to the present invention, the contents can be controlled while the process is being performed. Therefore, even if there is a variation between the wafers in the process and a variation between the chambers, the manufacturing is always performed with a constant quality. be able to. Moreover,
Even if an abnormality occurs in the equipment, the abnormality can be immediately detected and fed back, so that a large number of defective products will not be manufactured. it can. Therefore, as compared with off-line management, useless manufacturing processes such as defective products can be omitted, which greatly contributes to the improvement of product quality and cost reduction.

[Brief description of the drawings]

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

FIG. 2 is a configuration explanatory view of an example of the mass analyzer shown in FIG.

FIG. 3 is a diagram showing a relationship between a measured value of H ₂ ⁺ ion intensity and a USG film thickness when a USG film is formed according to the present invention.

FIG. 4 is a diagram showing a relationship between a measured value of PH ₃ ⁺ ion intensity and a P concentration when a PSG film is formed according to the present invention.

FIG. 5 is an explanatory view showing another embodiment of the process apparatus according to the present invention.

[Explanation of symbols]

 1 chamber 2 mass spectrometer

Claims (4)

[Claims] 1. A method for managing a wafer process in which a gas is introduced into a chamber and the gas reacts in the chamber to process a surface of a wafer provided in the chamber. A method of managing a wafer process, wherein a mass analyzer is attached to the wafer and the state of the process is managed by measuring a change of a specific element in the chamber by the mass analyzer. 2. The method according to claim 1, wherein an end of the process is determined by integrating an ion current of the specific element by the mass analyzer. 3. A process chamber for introducing and reacting a gas therein, and a mass analyzer for introducing a part of the gas in the process chamber. A process device that can detect the status of the reaction. 4. The process chamber has a plurality of chambers, the mass analyzer comprises one, and each of the plurality of chambers is connected to the mass analyzer via a valve. 4. The process in each of the plurality of chambers can be monitored by the switching operation.
Process equipment as described.