JP2003272984A - Manufacturing method for semiconductor equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for semiconductor equipment, in which secondary, tertiary damages are prevented from occurring. <P>SOLUTION: In the manufacturing method for semiconductor equipment in the use of a treating apparatus for processing a transported wafer, a sound collector is provided inside the apparatus for detecting sounds in the apparatus. Waveform of the detected sound is analyzed to detect a damage of the wafter. Thus, when a wafer is broken due to thermal stress, etc., the breakage can be so promptly detected that effect on other wafers or devices by foreign matters produced by the breakage of the wafer can be minimized. <P>COPYRIGHT: (C)2003,JPO

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 more particularly to a technique effectively applied to prevent damage to a wafer.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, a plurality of semiconductor elements or wiring patterns are collectively formed in a plurality of element forming regions provided on a wafer such as single crystal silicon to form a predetermined circuit, and adjacent elements are formed. The wafer is cut in the scribing region between the formation regions, and dicing is performed to separate each element formation region into individual semiconductor chips, and the individual semiconductor chips thus separated are fixed to, for example, a base substrate or a lead frame. A semiconductor device is completed through a mounting process such as die bonding and wire bonding and a sealing process such as resin sealing.

As described above, a semiconductor device is manufactured by subjecting a wafer to various treatments. In the process, the human body becomes a source of generation of foreign matter. Therefore, the wafer is stored in a cassette between steps. It is transported in a state of being sealed in a box or accommodated in a closed pod (FOUP: Front Opening Unified Pod), and the processing equipment is automated to promote unmanned operation for cleanliness.

[0004]

The various treatments applied in this way can result in damage to the wafer. For example, when a thin film is formed by heat treatment in a batch type vertical furnace, the wafer may be damaged due to an abnormality in the device. In particular, the wafer may be cracked by the thermal stress generated by the contraction of the wafer during cooling after the heating.

The diameter of the wafer is being increased in order to reduce the unit cost due to the increase in the number of simultaneous acquisitions. For example, when the diameter of the wafer is increased from 200 mm to 300 mm, the thickness is from 725 μm. Since the diameter is 775 μm, there is no corresponding increase in thickness with an increase in diameter. Therefore, assuming equivalent conditions, the bending stress generated on a 300 mm diameter wafer is about twice that of a 200 mm diameter wafer.
The wafer is more likely to be damaged.

Further, due to the increase in the diameter of the wafer, it becomes difficult to uniformly heat the entire surface of the wafer when heat-treating the wafer, which increases thermal stress due to uneven temperature distribution. Since the self-weight increases, the stress due to the self-weight also increases, so that the damage of the wafer becomes a greater problem.

When a wafer is damaged, in addition to a temporary damage in which the wafer is damaged by stress or the like, a secondary damage or a tertiary damage in which an adjacent wafer is damaged by fragments scattered from the damaged wafer may occur. Even if damage due to scattered debris does not result in damage, by continuing to process the wafer with debris adhered, for example, in the formation of an oxide film, the debris that has adhered may be an obstacle to oxidation, and conversely oxygen from the debris that adheres In some cases, a defect such as excessive supply of oxygen and excessive oxidation may occur. Further, the fragments of the scattered wafers due to the breakage may remain, which may affect the wafers of the next lot to be loaded, resulting in defects in other wafers.

The present inventors analyzed the cause of defective wafers, and in the data, about 40% to 45% of the causes of defects were caused by the device, and 18% of them were About 20%, that is, about a little less than half of the defects caused by the equipment, was due to the secondary damage and the tertiary damage.

Since the processing apparatus is unmanned as described above, the wafer is hard to be touched by human eyes, and no means for detecting damage to the wafer is provided. For this reason, continuing the processing without noticing the damage causes the damage to spread,
Alternatively, since the processing is continued even if the wafer is damaged, wasteful processing reduces the actual operating rate of the apparatus.

An object of the present invention is to solve these problems and to provide a technique capable of detecting damage to a wafer to prevent secondary damage and tertiary damage due to wafer damage. The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0011]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows. In a method of manufacturing a semiconductor device using a processing apparatus for processing a wafer that has been carried in, a wafer is damaged by providing sound collecting means for detecting a sound in the processing apparatus and analyzing a waveform of the detected sound. To detect.

According to the present invention described above, when a wafer is damaged due to thermal stress or the like, the damage can be quickly detected, so that the foreign matter caused by the damage of the wafer affects other wafers or devices. Can be minimized.

Embodiments of the present invention will be described below. In all the drawings for explaining the embodiments, the same reference numerals are given to those having the same function, and the repeated description thereof will be omitted.

[0014]

1 is a plan view showing the configuration of a vertical heating furnace used in a method of manufacturing a semiconductor device according to an embodiment of the present invention. A wafer 1 to be processed by using this heating furnace is sealed in a box while being housed in an open cassette 2, or a sealed pod (FOU).
P) and is carried into the cassette stage 3. The loaded wafer 1 is moved to the cassette shelf 5 by the robot arm 4 while being accommodated in the cassette 2.

The wafer 1 is transferred to the boat 8 in a lowered state by the wafer transfer machine 7 which moves up and down by the elevator 6. When the transfer of the wafers 1 is completed, the boat 8 is lifted by the elevator 9, and the boat 8 is moved to the inside of the heater 10 provided at the upper part and is heated.

When the temperature raising / heating / cooling processing is completed at a predetermined temperature / time, the boat 8 is lowered and the wafer 1 after the processing is returned to the cassette 2 by the wafer transfer machine 7.
The cassette 2 containing the wafer 1 is moved to the cassette stage 3 by the robot arm 4 and transferred to the next step.

In this heating furnace, the cassette stage 3-is used as a sound collecting means 11 for monitoring the sound generated during processing.
A microphone 11 a is attached between the cassette shelves 5, a microphone 11 b is attached to the wafer transfer device 7, and a microphone 11 c is attached to the boat 8. The microphone 11a may be attached to the robot arm 4, or the microphone 11b may be attached to the boat 8-.
It may be attached at an appropriate position between the cassette shelves 5. Further, since the microphone 11c attached to the boat 8 is heated to a high temperature, it may be a pickup that extracts the sound wave propagating in the boat outside the heater 10.

These sound collecting means 11 are connected to a detection device 13 housed in a control box 12 for controlling the temperature, time, etc. of heat treatment. The detection device 13 is provided with an analyzer that analyzes the waveform of the signal sent from the sound collecting means 11. When a waveform exceeding a certain time width and a predetermined peak value is generated, it is determined as an abnormal sound, A waveform analysis is performed to extract characteristics such as the time width and peak value of the abnormal sound, and it is determined whether or not the damage has occurred by comparing it with the waveform generated when the wafer is damaged, which is previously converted into data. In addition, although noise peculiar to the device is generated in the processing device, for example, a rotating fan of a cooling fan or an operating noise of an arm, the waveform of environmental noise is also recorded in advance as data. .

Next, detection of wafer breakage according to the present embodiment will be described with reference to the flow shown in FIG. 2 by taking the processing by the heating furnace as an example. When the wafer is loaded and processing is started, the monitor is started, and when abnormal sound is detected by the sound collecting means, the waveform of the abnormal sound is analyzed by the detection device and compared with the waveform of damage or the waveform of environmental noise which is made into data. Determine whether the wafer is damaged. As a result of the analysis, if it is not determined to be damaged, the process is continued as it is. Then, the operation of the cooling fan is stopped to prevent the secondary damage and the tertiary damage, or the operation of the robot arm or the transfer machine is stopped.

In the abnormal sound waveform analysis, the degree of breakage can be known to some extent by the strength of the peak value of the waveform, and the abnormal sound is analyzed from the characteristics that multiple peak values appear. It is possible to estimate whether or not fragments are scattered due to breakage and the size of the scattered fragments. In consideration of the extent of such damage and the progress of the treatment such as how far the heat treatment is progressing, the progress of the treatment such as the continuation of the treatment or the stop of the treatment is judged and a command is issued to the control device. After the processing is stopped, or after the processing is continued and the processing is completed, the processed wafers are collected, or the damaged wafers and fragments are collected, and the inside of the apparatus is cleaned.
By performing necessary measures such as washing, it becomes possible to restart the process promptly.

When a wafer is damaged, the waveform of the sound generated at the time of the recorded damage is registered as waveform data and converted into data, so that the subsequent judgment of damage can be performed with higher accuracy. Will be possible.

The manufacturing flow of a semiconductor device is shown in FIG. 3 as an example of a basic structure in which a MISFET is formed on the main surface of a semiconductor substrate and is connected by a wiring layer. In manufacturing a semiconductor device, first, a semiconductor substrate made of single crystal silicon or the like is prepared, impurities are implanted using a mask on which an oxide film is formed and patterned, and the implanted impurities are annealed by heat treatment to fill the buried layer. Alternatively, a well or the like is formed. Then, a nitride film is formed and an oxide film to be a field insulating film is formed using this nitride film as a mask.

Next, the nitride film and the oxide film in the element formation region are removed to form a thin gate insulating film, and then a metal film is laminated on the semiconductor film and patterned to form a gate. An insulating film is formed to cover the substrate, a source region and a drain region are formed by implanting impurities using the gate as a mask, and the implanted impurities are annealed by heat treatment to form an FET on the semiconductor substrate.

After that, an insulating film is formed and processed to form sidewalls, etc., an interlayer insulating film such as an oxide film is formed, a metal film to be wiring etc. is formed, and a protective film covering the whole is formed. Then, an opening such as a pad is provided in this protective film to complete the semiconductor device.

As described above, in the manufacture of a semiconductor device, a thin film formed and processed into an arbitrary shape is used as a constituent element of an element, or impurities are repeatedly injected through the thin film to form an element, and a protective film is formed. Complete the device by covering it. In addition to the formation of an oxide film by heating among these various treatments, the wafer is heated by many treatments such as heat treatment such as annealing and thin film formation treatment such as CVD (see FIG. 3).
In the drawing, the process of receiving heat is underlined), and the wafer is subjected to thermal stress due to contraction.

According to the present invention, when a wafer is damaged by such thermal stress, the damage can be detected promptly, so that the influence of foreign matter caused by the damage of the wafer on other wafers or devices can be minimized. It is possible to limit it. Further, even if the process does not receive heating, the wafer may be damaged when the wafer is handed over, etc. By applying the present invention, damage due to the wafer damage can be minimized.

In particular, in the case of batch type processing in which a plurality of wafers are processed at the same time, damage caused by affecting a damaged wafer to another wafer being processed at the same time can be minimized. It is valid. Further, in the case of the single-wafer processing, since the processing is continued even if the wafer is damaged, the actual operating rate of the apparatus is not lowered by performing wasteful processing, It is possible to prevent the processing from proceeding without noticing the damage of the wafer and to prevent the remaining pieces of the wafer from affecting the wafers to be processed later.

Although the present invention has been specifically described based on the above embodiment, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. Of course.

[0029]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows. (1) According to the present invention, there is an effect that it is possible to detect damage to a wafer that occurs during processing. (2) According to the present invention, due to the above effect (1), it is possible to minimize the influence of foreign matter caused by wafer damage. (3) According to the present invention, due to the above effect (2), there is an effect that the process yield can be improved. (4) According to the present invention, the effect (2) can improve the quality. (5) According to the present invention, due to the above effect (2), there is an effect that the operating rate of the device can be improved.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of a heating furnace used in an embodiment of the present invention.

FIG. 2 is a diagram showing a flow of detection of wafer breakage, which is an embodiment of the present invention.

FIG. 3 is a diagram showing a flow of manufacturing a semiconductor device.

[Explanation of symbols]

1 ... Wafer, 2 ... Cassette, 3 ... Cassette stage, 4
... Robot arm, 5 ... Cassette shelf, 6, 9 ... Elevator, 7 ... Wafer transfer machine, 8 ... Boat, 10 ... Heater, 1
1 ... Sound collecting means, 11a, 11b, 11c ... Microphone, 12
... control box, 13 ... detection device.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Teruo Sanji             5-20-1 Kamimizuhonmachi, Kodaira-shi, Tokyo Stock             Ceremony Company within Hitachi Semiconductor Group F-term (reference) 4K030 CA04 CA12 JA00 KA24 KA39

Claims (5)

[Claims] 1. A method of manufacturing a semiconductor device using a processing apparatus for processing a loaded wafer, wherein a sound collecting means for detecting a sound in the apparatus is provided in the processing apparatus. Production method. 2. A method of manufacturing a semiconductor device using a processing apparatus for processing a loaded wafer, wherein a sound collecting means for detecting sound in the apparatus is provided in the processing apparatus, and a waveform analysis of the detected sound is detected. A method for manufacturing a semiconductor device, characterized in that the damage to a wafer is detected by the device. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the treatment is a treatment involving heating. 4. The method of manufacturing a semiconductor device according to claim 1, wherein the process is a batch process. 5. The method according to claim 1, wherein when the damage of the wafer is detected, the subsequent processing is stopped.
The method for manufacturing a semiconductor device according to any one of 1.