JP3050284B2 - Semiconductor wafer etching equipment - 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 etching apparatus, and more particularly, to a wafer support boat having a support portion for supporting a semiconductor wafer for etching, cleaning and drying the semiconductor wafer in a reaction chamber. The present invention relates to a semiconductor wafer etching apparatus to be rotated.

[0002]

2. Description of the Related Art Generally, wet etching and dry etching are performed for etching an oxide film or the like on the surface of a semiconductor wafer.

In recent years, as the degree of integration of semiconductor devices has increased, it has become very strict to check for dust generated during the etching process and foreign substances and attached substances remaining on the semiconductor wafer surface after the etching process.

Therefore, in recent years, dry etching is generally performed rather than wet etching.

[0005] However, depending on the etching target, by-products remain on the surface of the semiconductor wafer after dry etching, so that cleaning and drying treatment after dry etching may be required.

[0006] The mainstream of the drying process after cleaning the semiconductor wafer is a spin dry method in which the semiconductor wafer is rotated and the moisture on the surface of the semiconductor wafer is sputtered by the centrifugal force. It is very important to balance during rotation of the wafer support boat supporting the wafers. For example, a rotation speed of 100
At 0 rpm, a balance in gram units is required.

Therefore, conventionally, in order to balance a wafer supporting boat supporting a rotating semiconductor wafer,
The weight and the hole are provided in a part of the wafer support boat.

The conventional wafer support boat provided with weights and holes in advance is designed to balance the rotating wafer support boat when supporting a certain number of semiconductor wafers. (Hereinafter referred to as orientation flat), the center of gravity of the semiconductor wafer is decentered from the rotation axis of the wafer support boat,
In addition, the weight of the semiconductor wafers supported by the wafer support boat varies depending on the number of wafers and the presence or absence of the orientation flat, and the weight of the wafer support boat changes for each etching process.

For this reason, during rotation, the balance of the wafer support boat is lost, and the wafer support boat vibrates and causes dust generation, and the semiconductor wafer jumps out of the wafer support boat due to centrifugal force. Was.

[0010] On the other hand, in the drying treatment without using the spin dry method, the use of isopropyl alcohol has been considered, but the fact that isopropyl alcohol is flammable,
There is a problem that organic matter remains on the surface of the semiconductor wafer after drying.

FIGS. 3A and 3B show a prior art wafer support boat used in a semiconductor wafer etching apparatus.

The wafer support boat shown in FIG. 3 is designed such that the center of gravity of the semiconductor wafer is shifted from the rotation axis of the wafer support boat in order to prevent the semiconductor wafer from jumping out due to centrifugal force during rotation of the wafer support boat. The wafer is supported by a support 13 'provided on the post 15'.

As described above, since the center of gravity of the semiconductor wafer is eccentric from the rotation axis of the wafer support boat, the weight 17 and the hole 18 for correcting the balance are provided on the roof in order to balance the rotating wafer support boat. 16 '(see FIG. 3A).

In such a wafer support boat, it is impossible to design a wafer support boat capable of achieving a perfect balance before manufacturing the wafer support boat. A balancing operation has been performed by using a support provided on the post or using an acceleration sensor.

In the balancing operation using the acceleration sensor, the "test weight" is attached and the wafer support boat is rotated, and the position of the "test weight" when the vibration of the rotating wafer support boat is minimized is determined by trial and error. It required a lot of trouble and time-consuming work such as finding the position of the weight and hole to correct the balance, and this work was costly.

Therefore, an object of the present invention is to eliminate the need for a balancing operation, to be free from the presence or absence of an orientation flat and the number of processed wafers, and to perform drying by a spin dry method without removing a semiconductor wafer from an etching apparatus after dry etching. Another object of the present invention is to provide an inexpensive etching apparatus which can be performed in the same apparatus.

[0017]

In order to solve the above problems, the present invention provides a method for etching a semiconductor wafer.
In a semiconductor wafer etching processing apparatus for rotating a wafer support boat having a support portion for supporting a semiconductor wafer in a reaction chamber, a center of gravity of the semiconductor wafer supported by the wafer support boat is positioned on a rotation axis of the wafer support boat. It is characterized by making it.

Here, the support portion is provided on each of the first and second support members that are detachably opposed to the wafer support boat, and the semiconductor wafer is provided on the first and second support members. It is supported by the support provided in each.

Further, spacers detachably disposed on the wafer support boat are arranged on the wafer support boat together with the first and second support members, and the number of semiconductor wafers to be processed and the distance between the semiconductor wafers (ie, , Pitch) can be changed.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a wafer for supporting a semiconductor wafer for etching, cleaning, and drying the semiconductor wafer and rotating the semiconductor wafer in a reaction chamber (see reference numeral 20 in FIG. 4). In a semiconductor wafer etching apparatus having a support boat (see reference numeral 10 in FIG. 4), as shown in FIG. 1A, the center of gravity of a semiconductor wafer supported by the wafer support boat is set on a rotation axis a of the wafer support boat. Is characterized in that

Here, a corrosion-resistant material is used for the wafer support boat to prevent corrosion of the wafer support boat during processing.

In order to balance the rotating wafer support boat by positioning the center of gravity of the wafer support boat when the support members 11 and 12 are disposed coaxially with the rotation axis a of the wafer support boat, Shape and support member 1
The shapes 1 and 12 are designed to be point-symmetric with respect to the rotation axis a. This eliminates the need for a balancing operation after the manufacture of the wafer support boat.

As shown in FIG. 1B, the support members 11 and 12 include a first support member 11 and a second support member 12, and the first and second support members 11 and 12
The wafer is removably opposed to the wafer support boat,
The semiconductor wafer is supported by support portions 13 provided on each of the second support members 11 and 12.

Here, the first and second support members 11, 1
When the first and second support members 11 and 12 are arranged on the wafer support boat facing each other, as described above,
The wafer support boats are arranged so as to be point-symmetric with respect to the rotation axis a.

The support members 11 and 12 are provided with through holes (see reference numeral 13c in FIG. 3) similar to the cross-sectional shape of the post 15, so that the support members 11 and 12 are provided.
2 can be detachably mounted on the wafer support boat.

Further, by arranging spacers 14 having through holes (not shown) having the same diameter as the through holes 13c together with the support members 11 and 12 through the posts 15, the support members 11 and 12 arranged on the wafer support boat are provided. And the distance between the support members arranged adjacent to each other in the vertical direction can be appropriately changed. That is, the number of semiconductor wafers to be processed and the pitch of the semiconductor wafers supported by the support member can be appropriately changed.

For example, when the support member supports 25 8-inch silicon wafers having an orientation flat, the weight of the silicon wafer without the orientation flat is 53 g, and the weight of the orientation flat portion is 0.29 g. So, 7.
The orientation flat side becomes lighter by 25 g, and is located at a position shifted by 0.55 mm from the center of the circular semiconductor wafer having the orientation flat to the opposite side of the orientation flat.

The shape of the support portion provided on the support member is a circle having the same shape as that of the semiconductor wafer.
When the center of the semiconductor wafer of inches is supported by the supporting portion such that the center of the semiconductor wafer is positioned on the rotation axis of the wafer support boat, the height of the wafer is 0.
It is designed to be 100.5 mm to allow 5 mm play. This play relates to the automatic transfer accuracy of the robot for transferring the semiconductor wafer to the support of the support member.

One wafer is 0.5 m from the center of the support.
In the case of a shift of m, a shift of 0.17 g occurs due to the above-mentioned play, but it is difficult to imagine that all 25 wafers are shifted in the same direction, and this shift is offset by the shift of the individual wafers. The center of gravity of the semiconductor wafer is located on the rotation axis of the wafer support boat when the semiconductor wafer is supported on the support portion of the support member arranged on the wafer support boat.

The support members 11 and 12 are made of wear-resistant engineering plastic such as Vespel (trade name, manufactured by DuPont).

When the supporting portion is designed so that the center of gravity of the semiconductor wafer having the orientation flat is located on the rotation axis of the wafer support boat, the rotation axis of the wafer support boat and the support member when the wafer is placed on the wafer support boat are designed. Although the center of the support portion is shifted, when such a wear-resistant engineering plastic is used for the support portion, since the specific gravity is 1.5 or less, the difference in weight between the front and rear sides of the support portion is reduced. Is 0.
Since the weight is about 015 g, this difference can be ignored.

When a corrosion-resistant metal such as Monel is used for the support portion, since the specific gravity is 8 or more, the difference in weight between the front and rear portions of the support portion due to the above-mentioned displacement is 0.3 g. For example, the front and rear portions of the support portion can be balanced by changing the thickness of the support portion at the time of design.

As described above, the first and second support members 1
When the first and second support members 11 and 12 support semiconductor wafers when the center of gravity of the wafer support boat coincides with the rotation axis a of the wafer support boat when the first and second support members are arranged on the wafer support boat. Since the center of gravity of the semiconductor wafer is positioned on the rotation axis a of the wafer support boat, the wafer support boat does not vibrate during rotation of the wafer support boat, and the semiconductor wafer does not fly out due to centrifugal force.

Further, the semiconductor wafer surface is efficiently exposed to an environment such as an etching gas introduced into the reaction chamber through a space between the first and second support members 11 and 12 disposed on the wafer support boat facing each other. The semiconductor wafer can be brought into good contact with each other, and at the time of drying after cleaning, the cleaning liquid or the like on the surface of the semiconductor wafer efficiently flows out through this space due to the centrifugal force of the wafer support boat.

FIGS. 2A, 2B and 2C show a support member arranged on a wafer support boat used in the semiconductor wafer etching apparatus of the present invention. The illustrated first and second support members 11, 12 each have a shape that is point-symmetrical with respect to its rotation axis when placed on a wafer support boat, and the support portions have abrasion resistance. Engineering plastic is used and the center of the support is on the center of gravity of the semiconductor wafer and the rotation axis of the wafer support boat.

The illustrated first and second support members 11 and 12
Have stepped portions 13a each having a shape corresponding to the peripheral shape of the semiconductor wafer and substantially matching the thickness of the semiconductor wafer.
A support surface 13b extending from the lower end of the step portion 13a to the center for mounting a semiconductor wafer; and a through hole having a shape similar to the cross-sectional shape of the post 15 provided on the wafer support boat. 13c and a through passage 13d having substantially the same height as the surface of the semiconductor wafer when the semiconductor wafer is supported, and penetrating the support members 11 and 12.

Here, the supporting surface 13b for mounting the semiconductor wafer has a plurality of claw-shaped supporting surfaces (reference numeral 13b in FIG. 2A) that extend from a part of the step portion 13a to the center.
Or a support surface having a shape extending from the lower end of the step 13a along the shape of the step 13a (see reference numeral 13b in FIG. 2B), Further, a support surface (a reference numeral 13b in FIG. 2C) in which a claw-like surface as shown in FIG. 2A is extended from a part of a portion extended from the lower end of the step 13a along the shape of the step 13 See also).

Since the semiconductor wafer etching processing apparatus of the present invention has the above-mentioned wafer support boat, a series of processing of semiconductor wafer etching, cleaning and drying can be performed by the same apparatus.

The semiconductor wafer etching apparatus of the present invention and the etching process will be described below. [Semiconductor Wafer Etching Processing Apparatus] The semiconductor wafer etching processing apparatus of the present invention is characterized in that the center of gravity of the semiconductor wafer supported by the above-mentioned wafer support boat is positioned on the rotation axis of the wafer support boat. As shown, SUS for etching a semiconductor wafer
+ Reaction chamber 20 made of Teflon or Ni-based corrosion-resistant alloy
And a wafer support boat 1 for supporting semiconductor wafers
0, the wafer support boat driving means 40 for rotating the wafer support boat 10, and the movement of the wafer support boat 10 to the inside and outside of the reaction chamber 20 (the direction of arrow M in FIG. 4).
Elevator means (not shown) for moving the door 30 for closing and opening the reaction chamber 20 at the same time
Consisting of

The wafer support boat 10 vertically stacks semiconductor wafers at regular intervals, and provides sealing means 3 provided on the door 30.
1 is connected to the wafer supporting boat driving means 40 via a shaft 41 passing through the wafer supporting boat driving means 4.
Rotated by zero.

Into the reaction chamber 20, an etching gas or pure water for cleaning is introduced into the reaction chamber 20 (FIG. 4).
Injector 21 for exhausting gas (see arrow F), and an exhaust port 22 for exhausting gas (see arrow G in FIG. 4).
And a drain port 23 for draining the cleaning liquid (see arrow L in FIG. 4). Here, the reaction chamber 2
Although the introduction of the etching gas and the pure water for cleaning into 0 is performed through one injector 21, an injector (not shown) for introducing the etching gas is provided as necessary.
Injectors (not shown) for cleaning and purging may be provided independently of each other.

The inner wall of the reaction chamber 20 is preferably
A cylindrical thin tube (not shown) connected to the injector 21 and having a large number of small holes is provided so as to surround the wafer support boat 10, and efficiently supplies an etching gas or the like to the semiconductor wafer disposed on the wafer support boat 10. Can be contacted. [Etching Processing] An etching processing method using the semiconductor wafer etching processing apparatus of the present invention includes the following steps (1) to (5).

(Step 1) Elevator means (not shown)
The wafer support boat 10 is moved to the outside of the reaction chamber 20 together with the door 30, and the desired number of semiconductor wafers are transported and supported on the wafer support boat 10 by the elevator means. Then, the reaction chamber 20 is hermetically closed by the door 30, and the inside of the reaction chamber 20 is substantially evacuated through the exhaust port 22.

(Step 2) Etching gas (HF or H
F / H 20) is introduced into the reaction chamber 20 through the injector 21. At this time, the HF gas has a purity of 9
More than 9.999% is used, and the ratio of HF / H20 is (0.001 to 100) / (99.999 to 0.0)
It is. The pressure at the time of etching is 5Pa-80000P
a, preferably 10 Pa to 13300 Pa.

(Step 3) After the completion of the etching, nitrogen gas is introduced through the injector 21 and the reaction chamber 20 is introduced.
The inside is returned to the atmospheric pressure, and then pure water for cleaning is introduced through the injector 21 to clean the semiconductor wafer. At this time, the wafer support boat driving means 40 rotates the wafer support boat 10 in order to uniformly clean the semiconductor wafer. Here, the rotation speed of the wafer support boat during cleaning is optimally 1 rpm to 1000 rpm.

(Step 4) After the cleaning, the injector 2
The wafer supporting boat 10 is rotated by the wafer supporting boat driving means 40 while introducing nitrogen gas through 1 to remove moisture on the surface of the semiconductor wafer by centrifugal force. The rotation speed of the wafer support boat 10 during drying is optimally 500
rpm to 2000 rpm. In order to promote the drying, a heater may be provided around the reaction chamber 20 and the door 30 to heat the introduced nitrogen gas to perform the drying. Drying may be carried out by reducing the pressure inside 20.

(Step 5) After the drying is completed, the wafer support boat 10 is moved to the outside of the reaction chamber 20 by the elevator means, and the semiconductor wafer is taken out from the wafer support boat 10.

[Brief description of the drawings]

FIG. 1 shows a wafer support boat of the present invention used in a semiconductor wafer etching processing apparatus, and FIG.
FIG. 1B is a plan view of a wafer support boat, and FIG.
It is a side view of a wafer support boat.

FIGS. 2A, 2B, and 2C are plan views of a support member provided on the wafer support boat of FIG. 1 for supporting a semiconductor wafer, respectively.

FIG. 3 shows a prior art wafer support boat used in a semiconductor wafer etching apparatus,
FIG. 3A is a plan view of the wafer support boat, and FIG.
FIG. 4 is a side view of a wafer support boat.

FIG. 4 is a schematic view of a semiconductor wafer etching processing apparatus.

[Explanation of symbols]

 10. . . Wafer support boat 11. . . First support member 12. . . Second support members 13, 13 '. . . Support 13a. . . Step 13b. . . Support surface 13c. . . Through hole 13d. . . 13. Passageway . . Spacers 15, 15 '. . . Post 16, 16 '. . . Roof 17. . . Balance correction weight 18. . . Balance adjustment hole 20. . . Reaction chamber 21. . . Injector 22. . . Exhaust port 23. . . Drain 30. . . Door 31. . . Sealing means 40. . . Boat driving means 41. . . Shaft a. . . F. Rotation axis of wafer support boat . . Introduction of processing gas etc. . . Exhaust of gas L. . . Drainage of washing water . . Door moving direction

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI H01L 21/68 H01L 21/68 T (56) References JP-A-63-104418 (JP, A) JP-A-1-302815 ( JP, A) JP-A-4-251956 (JP, A) JP-A-7-106271 (JP, A) JP-A-61-201340 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , (DB name) H01L 21/306 C23F 4/00 C23G 3/00 H01L 21/304 351 H01L 21/68

Claims (2)

(57) [Claims] 1. A semiconductor wafer etching process in which a series of processes of etching, cleaning, and drying of a semiconductor wafer is performed by the same apparatus by rotating a wafer support boat supporting a semiconductor wafer about a rotation axis in a reaction chamber. In the apparatus, the wafer support boats each have a support portion for supporting a semiconductor wafer on the wafer support boat, and are vertically stacked and arranged so as to be capable of loading and unloading semiconductor wafers in a horizontal direction. A plurality of sets of first and second support members, wherein the shapes of the first support member and the second support member disposed on the wafer support boat are symmetric with respect to a plane including the rotation axis, Each of the support portions of the first and second support members has a stepped portion having a shape corresponding to the shape of the periphery of the semiconductor wafer, and extends horizontally from the lower end of the stepped portion. The semiconductor wafer is disposed on the wafer support boat.
Each support of the first support member and the second support member
The semiconductor wafer is placed on
Wherein the to support in contact with the step portion, the step portion, the center of gravity of the semiconductor wafer is placed is provided so as to be positioned on the rotary shaft to the support surface, the first and second support members Wherein the center of gravity of the wafer support boat on which is disposed is located on the rotation axis. 2. A semiconductor wafer etching process in which a series of processes of etching, cleaning, and drying of a semiconductor wafer are performed by the same apparatus by rotating a wafer support boat, which supports the semiconductor wafer, about a rotation axis inside the reaction chamber. In the apparatus, the wafer support boats each have a support portion for supporting a semiconductor wafer on the wafer support boat, and are vertically stacked and arranged so as to be capable of loading and unloading semiconductor wafers in a horizontal direction. A plurality of sets of first and second support members, and the wafer support boat,
The wafer support bottle together with the first and second support members
Includes vertical stack to over preparative, spacers are arranged, the shape of the wafer the disposed in the support boat first support member and the second support member is symmetrical about a plane containing said rotation axis, said first Each of the support portions of the first and second support members comprises: a step portion having a shape along the periphery of the semiconductor wafer; and a support surface projecting horizontally from a lower end of the step portion. A center of gravity of the semiconductor wafer placed on the surface is provided on the rotation axis, and a center of gravity of the wafer support boat on which the first and second support members are arranged is located on the rotation axis. Semiconductor wafer etching equipment.