JP2663901B2 - Semiconductor wafer processing method and semiconductor wafer carrier changing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer processing method and a semiconductor wafer carrier changing machine.

[0002]

2. Description of the Related Art A predetermined number of semiconductor wafers in a semiconductor manufacturing process are collectively stored in a carrier, and are widely used for purposes such as transfer, wet processing, and temporary storage.
This type of carrier has a structure in which, for example, 24 or more semiconductor wafers are arranged inside with a predetermined gap. Such storage of the semiconductor wafer in the carrier, transfer of the carrier itself, transfer of the carrier into and out of the wet processing tank, removal of the semiconductor wafer from the carrier, and the like are performed automatically or semi-automatically semi-manually. I have.

[0003] A carrier containing a semiconductor wafer is introduced into the wet processing chamber, and the wet processing chamber is filled with an oxide film etching solution, an acid cleaning solution and the like required in a semiconductor manufacturing process.

When a predetermined circuit function is formed on the main surface of a semiconductor wafer, for example, when a gate oxide film is formed on the main surface, if particles such as impurities and contaminants are left on the main surface, a desired circuit function is formed. In some cases, characteristics cannot be obtained, and performing a wet treatment such as washing is an essential step in improving the production yield.

Here, the carrier accommodating the semiconductor wafer is required to have corrosion resistance to the processing solution. Therefore, the carrier for cleaning and the carrier for transfer and temporary storage (hereinafter referred to as a carrier for transport) are distinguished from each other. In many cases, a dedicated carrier is prepared for each. In this case, a change machine for transferring the semiconductor wafer from the carrier for transport to the carrier for cleaning or vice versa is required.

Referring to the side views of FIGS. 5A to 5E which sequentially show the state of semiconductor wafer replacement in such a changer, first, in FIG.
1. The transport carrier 34 is placed on the carrier stage 36 for wet processing and the carrier stage 35 for transport, respectively. In this case, a batch process is performed to transfer the semiconductor wafer 38 to the carrier 34 or the carrier 31 at once. The push-up device 33 is driven by a servomotor or the like, and gently slides upward through the openings (not shown) that are opened in the stage 35 and the carrier 34. At this time, the semiconductor wafer 38 is inserted into a groove (not shown) formed on the upper surface of the push-up device 33, and in this state, as shown in FIG. Is done. The holding device 37 is also formed with a groove for inserting each semiconductor wafer 38,
Even if the lifting device 3 is retracted downward, the semiconductor wafer 38 does not fall.

As shown in (C), the gripping device 37 horizontally moves from left to right, and stops at a predetermined position on the cleaning carrier 1. Next, the lower pusher 33 'ascends and releases each semiconductor wafer 38 into the groove formed on the upper surface of the pusher 33' at a time (D). Next, the push-up device 33 'slides gently upward to insert the semiconductor wafer 38 into the groove in the carrier 1 at a time.
Moves downward, and the gripping device 37 moves the semiconductor wafer 3
8 is released (E). Thus, the transfer from the transport carrier 34 to the cleaning carrier 41 is completed. Cleaning carrier 1 containing semiconductor wafer 8
Is mounted on a stage 36 and transferred to a washing tank (not shown) or the like, where various wet treatments are performed. After the processing is completed, the processing returns to the same or different prepared carrier 34 again from the stage 6 shown in FIG. In order to proceed to the next step, the carrier 34 on the stage 35 is transferred to another changer (not shown), and a carrier according to the process is prepared as appropriate.

As a known example of a semiconductor wafer refilling machine, referring to FIG. 6 described in Japanese Patent Application Laid-Open No. 4-332129, a first moving stage 45 dedicated to a carrier 48 for transport is provided. The semiconductor wafer 47 is transferred by sequentially moving the second moving stage 46 dedicated to the cleaning carrier 49, and the first push-up means 41 and the first holding unit 43 are dedicated to the cleaning wafer 49. And the second push-up means 42, the second gripper 44
Will be dedicated to the cleaned wafer, bringing dust and the like that have adhered to the carrier 48 into the cleaning process,
There is described an effect that impurities at the time of cleaning are not carried into the next step via the carrier 48.

[0009]

However, as described below, it has been found that particles attached to the main surface of the semiconductor wafer cannot be reduced uniformly in such a changer.

[0010] The semiconductor wafer in the cleaning carrier immediately after the completion of the cleaning process is taken out, and the number of particles attached to this surface is checked. Referring to FIG. 7, a predetermined circuit function is formed. The numerical value indicating the total number of attached particles (not the main surface opposite to the main surface of the wafer, that is, the one attached to the back surface) is shown as the vertical axis, and the horizontal axis represents the slot number (SLO) where the arranged semiconductor wafers exist.
T. No. ) Are shown in order from the first to the 25th. The main surface of the semiconductor wafer located at the first slot number faces substantially parallel to the inner surface of one side wall of the cleaning carrier, and the main surface of the semiconductor wafer is located between the side wall opposite to the one side wall and the first semiconductor wafer. , The semiconductor wafers located from the second to the 25th are interposed at a predetermined pitch,
Moreover, the main surfaces of the respective semiconductor wafers are commonly arranged so as to be substantially parallel to and opposed to the one side wall.

The back surface of the twenty-fifth semiconductor wafer faces the side wall opposite to the one side wall.

A method of irradiating a laser beam to the main surface of a particle mainly having a diameter of 0.2 μm or more and detecting and counting the scattered light, the total number of particles obtained is shown for each semiconductor wafer. ing. Three black circles are shown for each wafer, and this is data counted for each semiconductor wafer in the three carriers where the number of attached particles is particularly large. As is apparent from the figure, the total number of particles on the main surface of the semiconductor wafer located at the first slot number has reached 4 to 5 times as compared with the semiconductor wafer at the second transition. found. That is, the number of particles in the semiconductor wafer located at the first slot number having the main surface directly opposed to one side wall of the inner surface of the carrier is overwhelmingly large, and this is one of the main causes for lowering the manufacturing yield. Turned out to be. Moreover, it has been found that such particles are uniformly scattered on the main surface of the first semiconductor wafer.

As a first cause of the adhesion of the particles in such a state, the particles adhering particularly to the inner wall surface of the carrier are wetted toward the main surface of the semiconductor wafer located at the first slot number. It is conceivable that most of them are released by the treatment liquid and adhere to the main surface as they are. As a second cause of adhesion, a processing liquid having a relatively high flow velocity first collides with the first semiconductor wafer in the circulation path of the wet processing liquid containing particles, and at this time, particles of other parts are removed from the wafer. May adhere to the main surface. Further, as a third cause of adhesion, a vortex is locally generated when the processing liquid having a relatively high flow velocity first collides with the first semiconductor wafer, and the particles caught in the vortex are not discharged. It is conceivable that this is caused by the fact that it tends to remain on the main surface of the opposite wafer.

In order to eliminate the first cause of adhesion,
Each time a carrier is used, it is necessary to pass through a step of pre-cleaning the carrier itself, and thus there is a disadvantage that work efficiency is not improved. Further, even if a filter is provided in the circulation path in order to eliminate the second cause of adhesion, particles may be mixed in the processing liquid immediately after passing through the filter, and therefore, the filter alone cannot solve the problem. Further, when the flow path and the flowing direction of the processing liquid are changed so as to prevent the eddy current from occurring in order to eliminate the third cause of adhesion, the processing liquid does not uniformly rotate on the main surface of each semiconductor wafer.
A new problem of non-uniform processing arises.

In view of the above findings and problems, the present invention has the following problems.

(1) The number of particles adhering to the main surface of the semiconductor wafer should be kept below an allowable value.

(2) The control is not complicated, and only a simple uniaxial control device needs to be added.

(3) The carrier for transport and the carrier for cleaning need not be changed significantly.

(4) When each semiconductor wafer is moved so as not to be inserted into the groove located at the first position, the semiconductor wafer is not touched by the suction device,
Prevent new adhesion of particles.

(5) Each time the carrier is used, the carrier is not subjected to a washing step.

(6) Care must be taken to prevent a non-uniform processing solution from flowing around the main surface of each semiconductor wafer.

(7) To be able to manufacture semiconductor wafers with high reliability and high yield.

(8) Physical and chemical stresses that damage the main surface of each semiconductor wafer should not be applied.

(9) It is not necessary to add a step which causes an increase in particles.

[0025]

According to a first aspect of the present invention, there is provided:
A method of processing a semiconductor wafer, comprising a step of immersing a carrier containing semiconductor wafers in grooves arranged at a predetermined pitch in a wet processing liquid, wherein the carrier is closest to an inner side wall of the carrier facing a main surface of the semiconductor wafer. The above process is performed in a state where the dummy wafer is inserted into the groove at the position.

According to a second aspect of the present invention, there is provided a stage for mounting a carrier for inserting and storing semiconductor wafers in grooves arranged at a predetermined pitch, and for pushing up the semiconductor wafer stored in the grooves, A pusher for releasing the semiconductor wafer from the groove while maintaining a predetermined pitch, in a semiconductor wafer carrier changer, so that the main surface of the semiconductor wafer is separated from the inner side wall of the carrier, Control means for setting the semiconductor wafer at least at a pitch-moved state, and means for re-accommodating the semiconductor wafer moved by the control means in the carrier are provided.

A third structure of the present invention is characterized in that there is provided means for inserting a dummy wafer into a vacant groove created by the movement of the semiconductor wafer by the control means of the second structure.

In the second and third configurations, the control means is particularly provided in the stage or the push-up machine.

According to a fourth aspect of the present invention, there is provided a semiconductor device, comprising: first and third carriers for accommodating semiconductor wafers in grooves arranged at a predetermined pitch; In a semiconductor wafer carrier changing machine equipped with a push-up means and a gripping means for changing the wafer,
Control means for setting the semiconductor wafer so that the main surface of the semiconductor wafer moves at least one pitch in a direction away from the inner wall of the second carrier;
The second carrier is provided on any one of the stage on which the second carrier is placed, the push-up unit, and the holding unit.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 to FIG. 4 which sequentially show a change machine according to a first embodiment of the present invention, FIG. FIG. 2 is a cross-sectional view taken along the line AA ′ in FIG. 1, FIG. 3 is a cross-sectional view of the cleaning carrier showing a state of being refilled, FIG. It is sectional drawing of the washing | cleaning carrier which shows the state just before completion of refilling.

First, referring to FIG. 1 and FIG. 2, a change machine according to this embodiment includes a moving stage 2 on which a cleaning carrier 1 is mounted.
And a pair of stoppers 5 and 6 for defining a moving range of the stage 2, a fixed stage 4 to which the stoppers 5 and 6 are fixed, and a lifting machine 3.

Here, an opening 12 is provided at the bottom of the cleaning carrier 1, and the moving stage 2 and the fixed stage 4 also have openings corresponding to the opening 12. The pusher 3 can freely move up and down through these openings. In FIG. 1, the portions where the common structure is repeatedly provided on the left and right are omitted from illustration by using two break lines penetrating vertically. That is, the number of semiconductor wafers 9 to be housed is usually 10 or more and about 24, but only 10 are shown.
Correspondingly, the groove 7 of the lifting machine 3 is shown.

The carrier 1 contains 0.6 mm to 0.8 mm.
The ends of the semiconductor wafer 9 having a thickness of about 6 inches to about 8 inches are inserted into the grooves 8 formed at a pitch of 4.76 mm. , Are empty grooves into which the semiconductor wafer 9 is not inserted. Such a groove is not limited to a single groove, and two or more grooves may be present. In other words, the cleaning carrier 1 provided with the groove 8 in which one or more semiconductor wafers 9 are inserted at once is prepared in advance. In the semiconductor wafers 9 arranged at a predetermined pitch, the main surface, that is, the mirror surface on the side on which the circuit function is formed is all facing the left side. Therefore, the main surfaces of the inner wall 25 face each other.

The distance 23 between the side wall 24 and the center of the groove 8 of the semiconductor wafer at the closest position, that is, the first position of the slot number is about 14.53 mm, and the center of the last groove is about 14.53 mm. The distance 20 between the side walls 25 is also common to this. The gap 26 between the moving stage 2 and the stopper 6 is equal to the pitch of the groove 8.

Each of the grooves 7 formed at a predetermined pitch in the lifting machine 3 is formed with a taper 28 so that the semiconductor wafer 9 can be easily inserted. The moving stage 2 shown in FIG. 2 has a V-shaped cross section formed on the lower surface of the stage 2 so that the moving stage 2 does not move in the left-right direction and moves in the orthogonal direction. A V-shaped groove is formed in the fixed stage 4. Further, in FIG. 2, the left half is omitted since the center line 11 is set as a target axis and a line symmetry is established.

Next, as shown in FIG. 3, the push-up device 3 is gently moved upward, whereby the semiconductor wafers 9 are respectively inserted into the grooves 7, and the semiconductor wafers 9 inserted into the grooves are further inserted. Moves upward as it is, and rises until the semiconductor wafer 9 is separated from the groove 8. The carrier 1 from which the semiconductor wafer 9 has been released is moved leftward by an arrow 27 by a driving unit (not shown) and stopped by the stopper 6 on the left side. This moving distance corresponds to one pitch of the groove 8. Next, the pusher 3 is gently moved downward (in the direction of arrow 15) with the semiconductor wafer 9 placed thereon, and the semiconductor wafer 9 is stored in the groove 8 as shown in FIG. In the rightmost groove 8, the movement of the carrier 1 for one pitch causes
The semiconductor wafer 9 is stored. Therefore, the left groove 8, that is, the first groove 8 is an empty groove. As shown in FIG. 4, the semiconductor wafer 14 is inserted into the vacant groove from the direction of arrow 13 by means using tweezers, a suction device, or the like, or by hand league means.
Is inserted. The semiconductor wafer 14 is not a wafer to be incorporated into a semiconductor device later, but a so-called dummy wafer, and may be a trial or defective semiconductor wafer having substantially the same dimensions. May be formed so that symbols and numbers indicating the like can be visually recognized. This dummy wafer 14
Is stored in the wet processing liquid. Thereby, the flow path of the processing liquid flowing on the main surface of the semiconductor wafer 9 is uniformly adjusted, and is suppressed to be less than or equal to the number of adhered particles after the second in FIG.

As described above, the dummy wafer is placed in the first groove, and the wet processing common to the conventional one is performed.
There are no particles with a large number of particles attached, and all of the above-mentioned problems (1) to (9) are achieved.

As shown in FIG. 7, many particles adhere to the main surface of the first dummy wafer 14, but it is not a wafer to be manufactured and may be discarded. It is desirable to use the particles again after removing the particles.

When it is necessary to return the carrier after the wet processing to the arrangement of the semiconductor wafers shown in FIG. 1, the carrier is controlled to follow a path reverse to the above-described driving order.

In the above-described first embodiment, since the cleaning carrier 1 only needs to be moved by one pitch, there is no need to basically change the conventional driving method by adding a simple driving means. However, in addition to this, if the pusher 3 is moved rightward by one pitch without moving the mounting position of the carrier, and then the pusher 3 is stored again in the groove 8 of the carrier 1, The first groove is a vacant groove, and in this case, the above-described objects are achieved by inserting a dummy wafer into the groove.

The dimensions of the semiconductor wafer, the separation dimension, the pitch dimension, and the like shown in this embodiment are merely examples, and are not limited thereto. Needless to say, there are various variations. .

In the above embodiment, the same carrier 1 is placed so that a dummy wafer is stored in the first groove of the slot number.
In this embodiment, the sequence is rearranged and then sent to the wet processing step, but there is also an embodiment in which it is housed in another carrier.

This embodiment will be described as a second embodiment with reference to FIG. In the second embodiment, the stage 36 on which the cleaning carrier 31 shown in FIG. 5 is set is displaced from the stage 35 on which the transport carrier 34 is set by one pitch. For this reason, the holding device 31
When the wafer is accommodated in 1 (E), the first groove becomes an empty groove. A dummy wafer is inserted into this empty groove. Therefore, the cleaning carrier 31 having a number of grooves that is one or more than the number of grooves in the transport carrier 34 is easily provided.
Other driving orders are the same as those described with reference to FIG.

As the driving means of the second embodiment described above, the lifting device 33 may be shifted by one pitch so as to be gripped by the gripping device 37, or the gripping device 37 itself may be shifted by one pitch to perform another lifting. Or a pusher 3 into which a semiconductor wafer 38 has been inserted.
After shifting only 3 'by one pitch, the cleaning carrier 31 may be made to generate revenue. In short, the moving means of one pitch may be a moving means of a relative distance.

The second embodiment also achieves the above-mentioned objects (1) to (9). It is apparent that this embodiment can be appropriately incorporated in the known changer shown in FIG.

[0046]

As described above, according to the present invention,
By inserting the dummy wafer into the first groove of the slot number, it is possible to reduce the number of particles attached to the semiconductor wafer as a product, and to prevent scratches and contamination due to the use of tweezers and the like. ) To (9) are all achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state immediately before a change of a change machine of a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA 'of FIG.

FIG. 3 is a cross-sectional view illustrating a state of the first embodiment during replacement.

FIG. 4 is a cross-sectional view showing a state immediately before the end of the replacement according to the first embodiment.

5 (A) to 5 (E) are side views showing a sequence of changing a conventional changing machine.

FIG. 6 is an explanatory view of a known changer.

FIG. 7 is a characteristic diagram showing a state of particles adhering to a semiconductor wafer when wet processing is performed after using a conventional refilling machine.

[Explanation of symbols]

 1,31 Cleaning carrier 2,45,46 Moving stage 3,33,33 'Pusher 4 Fixed stage 5,6 Stopper 7,8 Groove 9,14,38,47 Semiconductor wafer 10,13,15,27 Arrow DESCRIPTION OF SYMBOLS 11 Center line 12 Opening 21 Wafer thickness 22 Pitch dimension 20, 23 Separation dimension 24, 25 Side wall 26 Gap dimension 28 Taper 34 Carrier 35, 36 Stage 37 Gripping device 41, 42 Pushing-up means 43, 44 Gripping portion 48, 49 Career

Claims (5)

(57) [Claims] 1. A method for processing a semiconductor wafer, comprising a step of immersing a carrier containing semiconductor wafers in grooves arranged at a predetermined pitch in a wet processing liquid, wherein the carrier is provided with a carrier facing a main surface of the semiconductor wafer. A method of processing a semiconductor wafer, wherein the step is performed in a state where a dummy wafer is inserted into a groove closest to an inner side wall. 2. A stage for mounting a carrier that inserts and stores semiconductor wafers in grooves arranged at a predetermined pitch, and pushes up the semiconductor wafer stored in the grooves to maintain the predetermined pitch. A semiconductor wafer carrier changer having a pusher for releasing the semiconductor wafer from the groove, wherein the semiconductor wafer is moved at least one pitch so that the main surface of the semiconductor wafer is separated from the inner side wall of the carrier. A semiconductor wafer carrier changer, comprising: a control unit for setting the semiconductor wafer; and a unit for re-storing the semiconductor wafer moved by the control unit in the carrier. 3. The semiconductor wafer according to claim 2, further comprising means for inserting a dummy wafer into a vacant space created by movement of said semiconductor wafer by said control means.
Carrier change machine. 4. The semiconductor wafer carrier changing machine according to claim 2, wherein said control means is provided on said stage or said push-up machine. 5. A first and a second carrier for accommodating a semiconductor wafer in grooves arranged at a predetermined pitch, and a push-up means for switching the semiconductor wafer from the first carrier into the second carrier. And a semiconductor wafer carrier changer equipped with gripping means, wherein the main surface of the semiconductor wafer is separated from the inner side wall of the second carrier,
Control means for setting the semiconductor wafer to be moved by at least one pitch is provided on any one of the stage on which the first and second carriers are mounted, the push-up means, and the gripping means. A semiconductor wafer carrier change machine characterized by the above-mentioned.