KR100244920B1 - Method for manufacturing semiconductor wafer - Google Patents

Abstract

The present invention relates to a method of manufacturing a semiconductor wafer.

In the method of manufacturing a semiconductor wafer, (1) forming a plurality of silicon rods in a plurality of single crystal growth groups, (2) slicing the silicon rods of (1) to a predetermined thickness and a plurality of wafers Forming (3) forming display means on which the history of the sliced wafer is recorded; and (4) simultaneously placing and grinding portions of the display means on which the same history is recorded in the step (3). (5) simultaneously batch-wrapping the ground wafers of (4), (6) simultaneously batch-polishing the wrapped wafers of (5), (7) the wrapped wafers of (6) Forming marking means for marking the history of the wafers on each wafer surface with reference to the display means of (3) on the wafer; and (8) cleaning the marked wafers of (7). It is done by

Therefore, even after the semiconductor device fabrication process, the history of each wafer can be traced to remove the cause of defects in the semiconductor device fabrication process.

Description

Method of manufacturing a semiconductor wafer

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a semiconductor wafer, and more particularly, to a method of manufacturing a semiconductor wafer which enables tracking of the wafer history such as the position of the wafer in the silicon rod even after the semiconductor device manufacturing process.

In general, a semiconductor device is constructed on a wafer, wherein the wafers used are thinly sliced single crystal silicon rods formed by the Czochralski crystal growth method or the Float Zone crystal growth method. It is then manufactured through subsequent processes such as grinding and lapping.

First, in the Czochralski crystal growth method, first, polycrystalline silicon is melted in a single crystal growth apparatus at about 1415 ° C., then the single crystal growth apparatus is rotated, and an arm with silicon seed crystals is transferred into the single crystal growth apparatus. Slowly descend to allow the silicon seed crystals to contact the surface of the molten silicon. When the lower end of the seed crystal starts to melt by contact with the molten silicon, the arm is slowly moved upward. As the arm moves upwards, the seed crystal and a part of the molten silicon in contact with the seed are pulled up, and in the process, the seed crystal is gradually grown by crystallization due to cooling of the molten silicon near the contact surface of the seed crystal. As a result, a single crystal silicon rod having the same crystal structure as the seed crystal is formed. One end of the silicon rod thus formed is called a seed part and the other end thereof is called a tail part.

In the float zone crystal growth method, a seed crystal is positioned inside, a polycrystalline silicon rod is introduced into a single crystal growth device supplied with an inert gas, and then the radio frequency coil formed outside the single crystal growth device is slowly rotated in one direction. As the polycrystalline silicon rod is melted as it moves, it is solidified again to form a silicon rod of the same single crystal as the seed crystal.

1 is a process chart for explaining a conventional method of manufacturing a semiconductor wafer using the single crystal growth method, Figure 2 is a graph showing the distribution of oxygen concentration from the seed region to the tail region of the silicon rod formed by the single crystal growth method, Figure 3 Is a graph showing the distribution of the number of COPs from the seed region to the tail region of the silicon rod formed by the single crystal growth method, and FIG. 4 is a graph showing the yield of a semiconductor device formed on a wafer formed by slicing the silicon rod formed by the single crystal growth method. to be.

Referring to FIG. 1, first, a plurality of single crystal silicon rods are formed in a plurality of single crystal growth phases by using the Czochralski crystal growth method or the float zone crystal growth method described above, and then a predetermined region of the silicon rods is removed to a subsequent process. This allows the flat zone of the wafer to be formed. In the single crystal silicon rod, a D-defect forming an octahedral void space may be formed by various causes such as a temperature difference in the single crystal growth group during the growth process, and during the subsequent polishing process, The upper portion of the D-fect may be cut and exposed to form Crystal Originated Particles (COPs) that are grooved in the wafer surface. In addition, as the oxygen (O ₂ ) component is included in the molten polycrystalline silicon inside the single crystal growth device, OP (Oxygen Precipitates) may occur in the wafer.

Subsequently, a slicing process of cutting the silicon rods at intervals of about 1 mm to form a plurality of wafers is performed. When the slicing process is performed, the amount of the single crystal silicon to be sliced is minimized.

Subsequently, the plurality of wafers are divided into a plurality of cassettes in the order of their position in the silicon rods, and a unique number of a single crystal growth group in which the single crystal growth process is performed on the surface of the cassette, and a unique number of silicon rods formed in the single crystal growth group. The label, which records the history of the wafer such as the number, the position of the wafer in the silicon rod, and the resistance of the wafer, is attached to the position where the subsequent process proceeds.

Next, the wafer contained in the cassette is taken out, followed by a grinding process of grinding the edges of the sliced wafer according to the crystallization direction of the single crystal silicon rod, and then divided into a cassette and moved to a position where the subsequent process proceeds. . The grinding process is performed because the surface of the wafer is roughened by the slicing process described above.

Subsequently, after the lapping process of taking out the wafer contained in the cassette and processing the thickness of the formed wafer about 1 mm is about 0.75 mm, the wafer is divided into cassettes and moved to a position where the subsequent process proceeds.

Subsequently, after the wafer contained in the cassette is taken out, the label attached to the cassette is referred to, and a single crystal growth process in which a single crystal growth process is performed on the flat zone of the polished wafer using a laser is performed. After the hard marking process for displaying the history of the wafer such as the unique number, the unique number of the single crystal silicon rod formed in the single crystal growth machine, the position of the wafer in the silicon rod, etc. with a specific code, the film is divided into the cassette again. Move to the position where the subsequent process proceeds. The marking depth is formed to about 40㎛.

Next, a polishing process of finely processing the surface of the wafer is performed.

Finally, the wafer fabrication process is completed by performing a cleaning process of removing impurities adsorbed on the surface of the wafer on which the marking process is performed using chemical.

However, in the silicon rod formed after the process of growing the single crystal silicon rod, as described in FIGS. 2 and 3, the oxygen component and the COP, that is, the defect are different from each other according to the position of the silicon rod, and thus, the wafer is manufactured. It can be seen that the semiconductor device fabricated on the wafer formed by the process shows different yields for each position of the silicon rods as shown in FIG. 4.

Therefore, the single crystal growth machine in which the wafer in which the semiconductor device manufacturing process has been performed has been processed with reference to the marking formed on the flat zone of the wafer by the above-described marking process, the silicon rod formed in the single crystal growth machine, the position of the wafer in the silicon rod, and the like. An analysis process is underway to determine the history of wafers.

However, if the wafers formed in different single crystal growth groups and different silicon rods are mixed with each other due to various causes during the slicing, grinding and lapping processes, and several wafers are damaged during the process, the damaged wafers are discarded. A single crystal growth machine, a silicon rod grown in the single crystal growth machine, and a silicon rod grown in the single crystal growth machine because other wafers are placed inside a cassette in which the processed and discarded wafer is to be placed, and thus the correct wafer history is not marked on the wafer by the marking process. There was a problem that it is not possible to easily trace the position of the wafer in the rod to eliminate the cause of the low yield.

In addition, by using a laser to mark the unique number of the single crystal growth group, the unique number of the single crystal silicon rod formed in the single crystal growth group, and the like on the flat zone of the wafer at a depth of about 40 μm. The semiconductor device formed on the flat zone of the wafer must be disposed of, and the wafer is impacted by the marking process with a depth of about 40 μm, which causes the defect of the semiconductor device formed by the subsequent semiconductor device manufacturing process. There was a problem acting.

An object of the present invention is to fabricate a semiconductor device on a wafer fabricated by slicing silicon rods formed by single crystal growth, and then to form a single crystal growth group in which a wafer is formed and a silicon rod formed from the single crystal growth group, and a wafer in the silicon rods. It is to provide a method of manufacturing a semiconductor wafer that can easily track the history of the wafer, such as the position.

Another object of the present invention is to provide a method of manufacturing a semiconductor wafer which can solve the problem of disposing of the semiconductor device formed on the surface of the wafer on which the marking process is performed.

Another object of the present invention is to provide a method of manufacturing a semiconductor wafer which prevents the wafer from being impacted by the progress of the marking step.

1 is a process chart for explaining a conventional method for manufacturing a semiconductor wafer.

Figure 2 is a graph showing the distribution of oxygen concentration from the seed region to the tail region of the silicon rod formed by the single crystal growth method.

Figure 3 is a graph showing the distribution of the number of COP from the seed region to the tail region of the silicon rod formed by the single crystal growth method.

4 is a graph showing the yield of a semiconductor device formed on a wafer formed by slicing a silicon rod formed by the single crystal growth method.

5 is a flowchart illustrating an embodiment of a method of manufacturing a semiconductor wafer according to the present invention.

In the method of manufacturing a semiconductor wafer according to the present invention for achieving the above object, in the method of manufacturing a semiconductor wafer, (1) forming a plurality of silicon rods in a plurality of single crystal growth apparatus, (2) said (1) Slicing a silicon rod to a predetermined thickness to form a plurality of wafers, (3) forming display means on which the history of the sliced wafers are recorded, and (4) the same history is Simultaneously batch-grinding the portion on which the written indicators are formed, (5) simultaneously batch-wrapping the ground wafers of (4), (6) simultaneously batch-polishing the wrapped wafers of (5) (7) forming marking means for marking the history of the wafers on each wafer surface with reference to the display means of (3) on the wrapped wafer of (6), and (8) the (7) marking And cleaning the wafers.

The display means of (3) can be formed on the surface of the cassette for moving the plurality of wafers formed by slicing the plurality of silicon rods to a subsequent process position.

The marking means may have a depth of about 1.5 μm to 3.5 μm on the edge of the wafer using a laser.

In addition, the step (7) may be performed immediately before the step (6) proceeds.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5 is a process chart for explaining an embodiment of a method of manufacturing a semiconductor wafer according to the present invention using the single crystal growth method.

Referring to FIG. 5, first, a single crystal silicon rod is formed by using Czochralski crystal growth method or float zone crystal growth method, and then, a predetermined region of the silicon rod is removed to form a flat zone portion of the wafer by a subsequent process. To help.

Subsequently, the slicing process is performed to cut the silicon rods at intervals of about 1 mm to form a plurality of wafers. When the slicing process is performed, the amount of the single crystal silicon to be sliced is minimized.

Subsequently, after dividing the plurality of wafers formed by the slicing process into the plurality of cassettes in the order of position in the silicon rod, the unique number of the cassette on the surface of the cassette, the unique number of the single crystal growth group in which the single crystal growth process is performed, A label in which the history of the wafer, such as the unique number of the silicon rod formed in the single crystal growth machine, the position of the wafer in the silicon rod, the resistance of the wafer, and the like is attached, is attached, and moved to a position where a subsequent process proceeds. At this time, when the wafer is broken by the slicing process described above, the position inside the cassette in which the broken wafer is located is kept empty.

Next, a batch grinding process is performed in which the edge of the wafer is polished according to the crystallization direction for each wafer formed by slicing the wafer inside the cassette and slicing the same silicon rod, and then dividing the wafer into the cassette for subsequent processing. Move to the position where the process proceeds. The grinding process is performed because the surface of the wafer is roughly formed by the slicing process described above. When the wafer is broken during the process, the inside of the cassette in which the broken wafer is to be placed is kept empty.

Subsequently, a batch lapping process is performed in which the wafers contained in the cassette are taken out, and the same silicon rods are sliced to process the thickness of the formed wafer about 0.7 mm by about 1 mm for each formed wafer. Move to the location where the subsequent process proceeds. If a broken wafer occurs during the batch-lapping process, the position inside the cassette where the broken wafer will be placed is left empty.

Subsequently, the wafers contained in the cassette are taken out, and the same silicon rods are sliced to perform a batch-polishing process for more precisely processing the surface of the wafer for each formed wafer, and then divided into cassettes and moved to a position where the subsequent process proceeds. . At this time, the upper part of the D-defect that can be formed during the single crystal growth process is cut and exposed to form COP. When a wafer is broken during the batch polishing process, the inside of the cassette in which the broken wafer is to be located is located. Keep the location empty.

Next, a unique number and a single crystal of the cassette for transporting the wafer to the edge of the polished wafer, that is, the dummy pattern is formed in a subsequent process, by taking out the wafer contained in the cassette and using a laser. Soft Marking that displays the history of the wafer, such as the unique number of the single crystal growth machine, the unique number of the single crystal silicon rod formed in the single crystal growth machine, and the position of the wafer in the single crystal silicon rod, using a specific code that can be recognized by the operator. After proceeding with the process, it is divided into cassettes and moved to the position where the subsequent process proceeds. The marking depth is formed in the range of about 1.5 μm to 3.5 μm, and after the soft marking process is performed after the batch-polishing process, the marking depth is lowered as compared with the conventional 40 μm. Although the sign is worn out, it may proceed before the batch-polishing process, depending on the intention of the manufacturer.

Finally, the wafer fabrication process is completed by taking out the wafer contained in the cassette and removing the foreign matter adsorbed on the surface of the wafer on which the marking process is performed using chemical.

If an abnormality such as an inoperability of the semiconductor device formed on the wafer occurs by a subsequent semiconductor device manufacturing process, the position of the wafer in the silicon rod is traced by referring to the history of the wafer marked on the wafer. Eliminate the cause.

Therefore, according to the present invention, a subsequent process of batch processing a plurality of wafers formed by slicing a plurality of silicon rods by silicon rods prevents mixing between different single crystal growth groups and wafers formed from different silicon rods until the soft marking process. By referring to the marking marked by the marking process, the unique number of the single crystal growth group, the unique number of the single crystal silicon rod formed in the single crystal growth group, and the position of the wafer in the single crystal silicon rod are tracked after the semiconductor device manufacturing process. There is an effect that can eliminate this low cause.

Since the marking depth of the marking process performed on the wafer is 1.5 μm to 3.5 μm, the marking depth is lower than that of the conventional about 40 μm, so that the wafer is impacted by the marking process and formed on the wafer by the subsequent process. There is an effect that can be prevented to act as a cause of failure.

In addition, since the marking process formed on the wafer proceeds to the edge portion of the wafer, that is, the portion where the dummy pattern is formed by the subsequent process, the semiconductor device formed in the region on the wafer where the marking process is performed has to be disposed of. There is an effect that can improve the yield by solving.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (6)

A method of manufacturing a semiconductor wafer, comprising the steps of: (1) forming a plurality of silicon rods in a plurality of single crystal growth groups, and (2) slicing the silicon rods of (1) to a predetermined thickness to form a plurality of wafers. (3) forming display means in which the history of the sliced wafer is recorded, (4) simultaneously placing and grinding a portion in which the display means in which the same history is recorded in the step (3) are formed, (5 ) Simultaneously batch-wrapping the ground wafers of (4), (6) simultaneously batch-polishing the wrapped wafers of (5), (7) onto the wrapped wafer of (6) (3) forming marking means for marking the history of the wafers on the surface of each wafer with reference to the display means of (3) and (8) cleaning the marked wafers of (7). My Way. The method of manufacturing a semiconductor wafer according to claim 1, wherein the display means of (3) is formed on a surface of a cassette for moving a plurality of wafers formed by slicing the plurality of silicon rods to a subsequent process position. The method of claim 1, wherein the marking means is formed using a laser. The method of claim 3, wherein the marking means is formed at an edge of the wafer using a laser. The method of claim 4, wherein the marking means is formed at a depth of about 1.5 μm to 3.5 μm at an edge portion of the wafer using a laser. The method of manufacturing a semiconductor wafer according to claim 1, wherein the step (7) is performed immediately before the step (6) proceeds.

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