JPH0541353A - Method of discriminating apparatus for wafer process use - Google Patents

Abstract

PURPOSE:To easily specify, for each wafer, a process apparatus used in a manufacturing process when the cause of an abnormality or a defect in a wafer process including a wafer treatment process is traced and investigated by using the process apparatus which utilizes a plasma. CONSTITUTION:When a wafer 1 is treated inside a process apparatus utilizing a plasma, a recessed and protruding part SR having a pattern peculiar to the apparatus is formed at the inner circumference of a ring-shaped clamp jig 15 which carries and holds its peripheral edge part. During its treatment, the pattern of the recessed and protruding part SR is transferred automatically to the peripheral edge part of the wafer 1 from the clamp jig 15. The process apparatus which has executed the treatment can be specified from the pattern of the transferred recessed and protruding part SR and from the position with reference to an orientation flat 1a of the wafer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer process including a step of processing a wafer in a plasma utilizing process device, and a device used for the wafer process for each wafer for managing a process device and a process using the process device. It relates to an advantageous method for identification.

[0002]

2. Description of the Related Art Plasma etching apparatus, plasma CV
As is well known, a process device utilizing plasma such as a D device and a sputtering device performs various processes such as etching and film formation on a semiconductor wafer by a so-called dry process, and management of process conditions is easier than a wet process. It is easy to use, has high processing accuracy, and has the advantage of being able to simplify post-processing such as cleaning. Therefore, it has been more and more widely adopted for a wafer process in mass production of semiconductor devices, particularly integrated circuit devices.

In the wafer process, of course, the process conditions are controlled for each step and the process is carried out while performing necessary measurements in the main steps, and a precise characteristic test is performed on the wafer after all the steps. Abnormalities may be discovered during measurement or testing during or after the end of the process.If an abnormality leads to poor performance or characteristics, it is necessary to thoroughly investigate the cause of the occurrence by tracing back the process up to that point in order to prevent recurrence. There is. Conventionally, this follow-up investigation is usually carried out while carefully comparing the measurement and test results for the wafer in question with the record of the process conditions of the process equipment used for the wafer process.

[0004]

However, in a mass production site of semiconductor devices, various process devices are used in a wafer process line, and a plurality of process devices are often used for the same process. In the follow-up investigation of the cause of the abnormality or defect, it may not always be easy to accurately pinpoint the process that actually has a problem in the process and the process equipment used for it.

One of the reasons why the follow-up investigation is difficult is that the cause of the abnormality or defect may extend over a plurality of steps. In this case, the cause should be as accurate as possible for each process step and the process equipment used for it. Need to be separated.
Another reason peculiar to the manufacturing of the semiconductor device is that the cause of the failure is often contamination in the process equipment. Of course, in this case, it is necessary to accurately identify the process equipment as the contamination source. In either case, it is important to separate each process or process device that causes an abnormality or defect, but the fact that this separation has been insufficient in the past has been a bottleneck in follow-up investigations.

In view of the above circumstances, an object of the present invention is to facilitate the identification of the plasma-using process equipment used in the main process of each wafer when the cause of abnormalities or defects in the wafer process is traced and investigated. is there.

[0007]

According to the method for identifying a process apparatus of the present invention, the object is to provide an inner circumference of an annular clamp jig used to hold a peripheral portion of a wafer in a plasma-utilized process apparatus. By forming unevenness peculiar to the device on the wafer, this unevenness is transferred from the clamp jig to the peripheral edge of the wafer during the process in the device, and the unevenness transferred to the wafer through the wafer process is changed to the wafer process. It is achieved by enabling identification of the process equipment used for each step in.

The unevenness provided on the clamp jig in the above-described structure is set as a tooth profile representing a code pattern unique to a process device, and the number of teeth and the arrangement pitch are made different for each device, or the unevenness is formed as a groove. It is advantageous to make the width of the jig in the inner circumferential direction different for each device. In addition, since the wafer always has a notch portion called an orientation flat at the periphery for positioning or the like, the circumferential position of the unevenness representing the code pattern unique to each device with respect to the orientation flat is determined as a step or a step in the wafer process. It is very advantageous to set different factors for each process type in order to accurately separate the factors for each process in the follow-up investigation of the cause of defects and the like.

[0009]

According to the present invention, the plasma utilizing process apparatus uses the annular clamp jig for holding the peripheral edge of the wafer for holding and cooling the wafer, and after performing a predetermined process on the wafer in the apparatus. The focus is on the fact that there is a clear difference between the part hidden under the jig and the part exposed from the jig to the extent that it can be easily distinguished even at a glance. As described above, by simply providing unevenness representing the code pattern unique to each device on the inner circumference of this annular clamp jig, the clamp can be performed without taking any special measures when performing a predetermined process in the device. By automatically transferring this code pattern from the jig to the peripheral portion of the wafer, the process equipment used in the wafer process and the steps performed by it can be easily specified later. Those were.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 (a) is a cross-sectional view illustrating a plasma-utilized process apparatus for carrying out the method of the present invention, FIG. 1 (b) is a top view of a clamp jig and a wafer portion thereof, and FIGS. )
FIG. 3 is a top view showing respective aspects of code patterns transferred to a wafer by the method of the present invention.

The process apparatus 10 shown in FIG. 1 (a) is, for example, a plasma etching apparatus, and its vacuum container is generally used.
In this embodiment, in which the wafer 1 is placed inside 11, a lower electrode 12 and an upper electrode 13 facing the lower electrode 12 are provided, and a high frequency power source 20 is connected to a lead led out of the upper electrode 13 to the outside of the vacuum container 11 via an insulation 13a. By applying a high-frequency voltage by the plasma, plasma is generated in the depressurized space between the electrodes 12 and 13. The vacuum container 11 is provided with an introduction pipe 11a for the process gas PG to be ionized in the plasma and an exhaust pipe 11b connected to the vacuum V for decompressing the inside.

The lower electrode 12 is fixed to the bottom of the vacuum chamber 11 via a base 14 as shown in the figure, for holding the wafer 1 at a regular position on the upper surface thereof and keeping it in good contact with it to maintain a predetermined temperature. A clamp jig 15 is provided for this purpose. The clamp jig 15 is formed in an annular shape so as to hold the peripheral edge of the wafer 1 together with the lower electrode 12, and is illustrated by an operation mechanism (not shown) housed in the base 14 via a plurality of thin pins 15a. It is operated in the vertical direction shown in UD. The peripheral portion of the wafer 1 held by the clamp mechanism is usually within the range of 2 to 3 mm.

To load the wafer 1 onto the lower electrode 12,
The clamp jig 15 is usually first lifted upward by pneumatic operation by the above-mentioned operation mechanism, and then placed on the lower electrode 12 from the window 16 of the vacuum container 11 by a wafer loading / unloading device as usual. Then, the clamp jig 15 is downwardly operated by air pressure to clamp the wafer 1 on the upper surface thereof with a predetermined pressure. The removal of the wafer 1 to the outside of the vacuum container 11 after the completion of the process is, of course, performed in the reverse order.

In the present invention, as shown in FIG. 1 (b), the inner periphery of the portion of the clamp jig 15 that contacts the peripheral portion of the wafer 1
The unevenness SR is provided on 15b and has a shape representing a code pattern unique to the process apparatus 10. In the illustrated embodiment, the unevenness SR has a tooth shape, and a simple code pattern P2 having, for example, two teeth is represented. It is preferable that the tooth profile of the unevenness SR has a pitch or size of, for example, 1 to several mm, which is easily visible, and the tooth profile is smaller than the size of the chip formed in the wafer 1 and the integrated circuit of the chip. By making the size larger than the pattern, it is possible to easily identify the code pattern P2.

The method of the present invention is different from the conventional one in that the unevenness SR is provided on the clamp jig 15 in this way, and there is no difference in the operation of the process apparatus 10 from the conventional one. In the embodiment of FIG. The insulating film or the metal film may be etched in a plasma atmosphere under a reduced pressure of a normal fluorine-based or chlorine-based process gas PG. Of course, this etching process does not cover the wafer 1
Since it is considered to be the surface of the clamp jig 15, the unevenness SR of the clamp jig 15 is unique to each process device 10 due to the insulating film and the metal film left unetched on the peripheral portion of the wafer 1 taken out from the process device 10 after the processing. The code pattern P2 is transferred.

FIG. 2 shows some aspects of imparting this code pattern to the wafer 1. In the example of the embodiment shown in FIG.
Similarly, the code patterns P1 to P3 represented by tooth shapes are given to the peripheral edge of the wafer 1, but the number of teeth thereof is set to 1 to 3 peculiar to each process apparatus, and its position relative to the orientation flat 1a. Are shifted in the circumferential direction according to the order of steps in the wafer process. When the wafer 1 is loaded into the process apparatus 10 of FIG. 1 (a), the wafer loading / unloading device and the like described above position the wafer 1 with reference to the orientation flat 1a. The circumferential position of the code patterns P1 to P3 with respect to the orientation flat 1a can be easily set by the position where the unevenness SR is formed and placed on the 15b. In this way, by making the code pattern different for each device as well as for each process, it is possible to further easily identify the process device.

In the embodiment shown in FIG. 2B, the code pattern Q1
Same as (a) in the figure, the position of Q3 is shifted relative to the orientation flat 1a for each process, but the width in the different circumferential direction for each process device is, for example, 1 to 3 times the ratio. Is set to. In this embodiment as well, it is possible to easily specify the process device from the widths of the code patterns Q1 to Q3, and further to specify the process sequence during the wafer process from those positions.

As can be seen from these embodiments of FIG. 2, in the method of the present invention, the clamp jig 15 of each process apparatus 10 is used.
With respect to the unevenness SR provided on the inner circumference 15b, various selections regarding the shape, pattern, position, etc. can be made within the above-mentioned summary. Further, although the process apparatus is a plasma etching apparatus in the embodiment of FIG. 1, it is not limited to the method of the present invention, but a general process for performing etching or film formation on a wafer by a plasma utilizing process apparatus such as a plasma CVD apparatus or a sputtering apparatus. Applicable to

[0019]

As can be seen from the embodiments described above, in the method for identifying a wafer processing apparatus according to the present invention, the inner periphery of an annular clamp jig that holds the peripheral edge of the wafer of the plasma processing apparatus is used. By forming and placing the unevenness unique to the device and automatically transferring this unevenness from the clamp jig to the peripheral edge of the wafer during the process in the device, a predetermined process is performed on the wafer in each process device during the wafer process. Even if no special measures are taken when performing the process, the unevenness or code pattern unique to the device is automatically applied to the peripheral edge of the wafer to trace the cause when a process abnormality or defect occurs. It is possible to easily and accurately specify the process equipment used in the wafer process for the investigation.

Furthermore, if the circumferential position of the unevenness of the wafer provided on the clamp jig with respect to the orientation flat is made different for each process, it is possible to easily specify the order of processes using the apparatus within the wafer process.

[Brief description of drawings]

FIG. 1 shows an embodiment of the identification method of the present invention, where FIG. 1 (a) is a cross-sectional view of a process device as an object of its implementation, and FIG. 1 (b).
[Fig. 3] is a top view of the clamp jig and the wafer.

FIG. 2 is a top view of a wafer illustrating an uneven pattern transferred onto a wafer by the method of the present invention, and FIGS. 2 (a) and 2 (b) show different aspects thereof.

[Explanation of symbols]

 1 Wafer 1a Wafer orientation flat 10 Plasma etching device as a process device 15 Clamping jig 15b Clamping jig inner circumference SR Concavity and convexity P1 Code pattern represented by irregularity P2 Code pattern represented by irregularity P3 Code pattern represented by irregularity Q1 Code represented by irregularity Pattern Q2 Code pattern represented by unevenness Q3 Code pattern represented by unevenness

Claims (3)

[Claims] 1. In a wafer process including a step of processing a wafer in a plasma utilizing process apparatus, the apparatus is unique to the inner circumference of an annular clamp jig that holds the peripheral edge of the wafer during the process in the apparatus. A wafer process characterized in that various peripheral irregularities are formed and placed, and the device used for the process can be specified by the irregularities transferred from the clamp jig to the peripheral edge of each wafer that has undergone the wafer process. Device identification method. 2. The method for identifying a wafer processing apparatus according to claim 1, wherein the unevenness provided on the clamp jig is a tooth profile representing a code pattern unique to the apparatus. 3. The wafer process apparatus according to claim 1, wherein the circumferential position of the unevenness of the wafer provided on the clamp jig with respect to the orientation flat is changed for each process using the apparatus. Method.