JPS62165931A - Ashing device - Google Patents

Abstract

PURPOSE:To obtain a device ashing and removing a film adhered on a wafer at high speed by forming a gas-flow space containing O3, brought into contact with the wafer and selecting O3 content at 3-5wt%. CONSTITUTION:A gas outflow section 22 is oppositely arranged separated at a set interval from a wafer, a large number of holes are disposed equally to a plate section in the outflow section or a locus in which a porous substance or a tubular material is turned horizontally is used, and a gas is fed uniformly onto the surface of the wafer. A cooler is mounted to the outflow section 22. O2 is supplied and O3 is generated and a flow rate is controlled, O3 content in O3+O2 is brought to 3-5wt%, the temperature of the gas is cooled at 15-50 deg.C, the gas is fed equally onto the wafer 28 temperature-controlled 6 at 150-500 deg.C, and a reaction product gas is discharged 4. The wafer or the outflow section 22 can be moved vertically. According to the device, a film applied onto the wafer is exposed efficiently to O radicals conducting an extremely strong oxidative effect, thus allowing ashing treatment at a high speed.

Description

[Detailed Description of the Invention] [Field of Application of Sanmata 1.] This invention relates to an ashing device (ashing device) for removing a film deposited on a wafer η, and in particular, the present invention relates to an ashing device (ashing device) for removing a film deposited on a wafer η. The present invention relates to an ashing device suitable for single-layer processing for removing a photoresist film (hereinafter referred to as "resist") by oxidizing it.

[Prior art] 1. Formation of fine patterns on conductor integrated circuits is performed by using a resist film of organic polymer formed on the wafer [-1] as a mask by exposure and development. This is done by etching the underlying film.

Therefore, the resist film used as a mask needs to be removed from the surface of the wafer after the etching process. Ashing processing is performed to remove the resist in such a case.

This ashing process is called registry stripping.

It is also used for cleaning wafers and masks, removing ink, removing solvent residue, etc., and is suitable for dry cleaning in the ``1'' conductor process.

Ashing processing for resist removal is generally performed using oxygen plasma.

In Rennost asson/g using oxygen plasma, a wafer with a resist film is placed in a processing chamber, and the oxygen gas introduced into the processing chamber is turned into plasma by a high-frequency electric field, and the generated oxygen source ranocal is applied to a percussion tool. This method utilizes the action of oxidizing a certain renost to decompose it into carbon dioxide, carbon oxide, and water, which are then vaporized.

However, in the ashing process using oxygen plasma, the wafer is irradiated with ions and electrons accelerated by the electric field existing in the plasma, which has a negative effect on the electrical characteristics of the conductor integrated circuit. There are drawbacks.

To avoid such drawbacks, UV light (
There is a device that generates oxygen radicals by irradiating 116 UV rays and performs an ashing process by punching. Compared to plasma processing, this type of apparatus has the advantage of being able to perform efficient stripping and cleaning without damaging the elements, since there is almost no damage to the elements caused by the electric field.

FIG. 17 shows a conventional ashing process using ultraviolet irradiation.

A large number of wafers toi,i are placed in the processing chamber 100.

1... are arranged vertically at predetermined intervals, and the processing chamber 1...
Ultraviolet rays from an ultraviolet light emitting tube 103 installed in the 1st part of the processing chamber 100 are irradiated through a transparent window 102 made of quartz or the like provided in the first part of the processing chamber 100 to excite the oxygen filled in the processing chamber 100. to generate ozone. Oxygen atom radicals generated from this ozone atmosphere are then made to act on the wafer 101 to carry out an unwinding process.

Incidentally, in recent years, wafers have tended to have a diameter of 1-1 mm, and in response to this trend, a wafer processing method in which wafers are processed one by one is becoming common.

[Problems to be Solved] Although the ashing process using ultraviolet irradiation described above has a considerable advantage in preventing damage to the wafer, it has disadvantages in that it is a batch process. Moreover, since it works in an ozone atmosphere called tll-, the rental song speed is 500 to 1500 people/
It is only about mln.

However, in single wafer processing suitable for the human L1 diameter, the processing speed is usually 1 μm to 2 μm/min.
Conventional equipment that emits ultraviolet rays at 11 (1 minute) cannot handle single wafer processing at 1 minute.

Furthermore, since ultraviolet rays are used, the device has to be large and expensive.

[Purpose of the Invention] This invention has been made in view of the problems of the prior art. listen,
An object of the present invention is to provide an ashing device that does not require the use of ultraviolet rays or the like.

[Means for Solving the Problems] The first stage of the ashing apparatus of the present invention to achieve the above object is to provide a flow space in contact with the wafer through which a gas containing ozone flows. Is it coated on the wafer surface? The film is removed by oxidation, and the ozone content is in the range of 3% to 5%.

[Operation: For example, an ozone outlet is provided at a position facing the wafer at a predetermined distance to form an ozone + oxygen gas flow space between the wafer and the ozone content to be 3% by weight. By setting the ozone in the range of ~5 tons M%, new ozone can be efficiently continuously supplied to the wafer, promoting the oxidation chemical reaction between oxygen atomic radicals and the film deposited on the wafer, and Non-radical oxygen (0
By 2), carbon dioxide, -carbon oxide, water, etc. generated after the reaction can be moved and discharged from the wafer surface in a vaporized state.

As a result, the reaction surface of the film 9 deposited on the wafer 1-, for example, any film, can be efficiently exposed to the oxygen source r-Ranchal, which has an extremely strong oxidizing action. .

Therefore, it is possible to carry out high-speed ashing processing, and it is possible to realize an ashing apparatus suitable for single-wafer processing.

[Example Code] An example of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of an ashing processing system according to an embodiment to which the ashing apparatus of the present invention is applied, and FIG. 2 is a block diagram of another similar embodiment, showing the overall configuration including a wafer transport mechanism. 3 (a) and (b)
) is a specific explanatory diagram of the electrostatic chuck in the wafer transfer mechanism, in which (a) is a cross-sectional view taken along line I-i in (b) of the same figure, (b) is a cross-sectional view of The figure is an enlarged explanatory diagram of the reaction part, Figure 5 (a) is a diagram explaining the relationship between reaction and movement by oxygen atom radicals, and Figure 5 (b) and (C) are the amount of diffusion, respectively. 1] FIG. 6 is a graph explaining the relationship between the decomposition half-life of ozone and the 11+λ degree of the diffusion opening.

Furthermore, FIG. 7 is a graph explaining the relationship between the ashing rate and the gas flow [4] at a wafer surface temperature of 300°C, and FIG. FIG. 9 is a graph explaining the relationship between ashing speed, and FIG. 10 is an explanatory diagram showing the relationship between gas temperature and resist removal rate.
), (b), (c), and (d) are the opening l of the diffuser plate, respectively.
Explanatory diagram of a specific example of -1, Fig. 11 (a), (bL (
c) and (d) are explanatory diagrams of a 3-1 example of the gas cooling structure in the injection part, respectively. Fig. 12 (a) is an explanatory diagram of a method for rotating the gas injection part, and Fig. 12 (b) 13 is an explanatory diagram of the ashing effect when the wafer side is not rotated. FIG. 14 is a block diagram of an embodiment of the ashing processing system that determines the end of the ashing process. FIG. 15 is a graph of changes in the concentration of carbon dioxide in gas, and FIG. 16 is a graph illustrating the relationship between the ashing rate and the ozone rate.

In FIG. 1, reference numeral 1 denotes an ashing processing station t, which includes an ashing device 2, an ozonator oxygen gas supply device 3 that supplies oxygen gas containing ozone to the ashing device 2, and 1 to the ashing device 2. The heat generation state of the connected υl-air device 4, the lowering device 5 for moving the wafer mounting table 21 disposed inside the ashing device 2 upward, and the heating device 21a installed inside the wafer mounting table 21. and a temperature regulator 6 that controls the temperature of the wafer by adjusting the temperature of the wafer.

The ozone + oxygen gas supply device 3 includes a gas flow M regulator 3
a, an ozone generator 3b, and an oxygen supply source 3C. container 3b, oxygen supply source 3c,
υ1: Adjusted in relation to the air device 4.

The ozone concentration supplied to the ashing device 2 for the cows is adjusted by the ozone generator Z3b and set to a predetermined value.

Further, the wafer mounting table 21 disposed inside the ashing device 2 holds the wafer 28 by suction.
The 1KrL degree of the wafer 28 subjected to X+,'r is 7! u1
It is maintained at a predetermined value by the degree adjuster 6.

-1 part of the wafer 28 has a surface area of 0.5 to 20
A cone-shaped injection part 22 is provided that injects ozone + oxygen gas at intervals of about mm,
The interval 111 is set to a predetermined value by raising the wafer mounting table 21 by the chemical lifting device 5. In this case, the injection part 22 side may be moved down by 1.0 kV using a kV lowering device.

The injection ffl< 22 is made of SUS (stainless steel) or AJI, and opposite to the wafer 28 is a disc-shaped diffusion plate f parallel to the surface of the wafer 28.
fl<22a. In order to process the loading and unloading of the wafer 28, the wafer mounting table 21 is lowered by the IiC unloading device 5, the space between the diffusion plate section 22 and the wafer 28 is expanded, and the wafer transport mechanism is placed in the space. This is done by the intrusion of the arm.

Now, for the ashing process, the wafer 28 on the wafer mounting table 211 is heated in a range of about 150°C to 500°C,
The wafer is then heated to a specific temperature of 200 DEG C. to 350 DEG C., and the mixing ratio of ozone and oxygen produced by the ozone is adjusted to 1 by the ozone generator 3c. And oxygen gas impregnates this ozone.

For example, a culm of 3λ to 15λ/min is sent into the chamber of the ashing device 2, which is a processing chamber. The gas pressure inside the ashing device 2 at this time is, for example, 700 to 200 Torr.
Set it to a range of about r.

Next, loading and unloading processing of the wafer 28 into and out of the processing chamber of the ashing apparatus 2 will be specifically explained based on the ashing apparatus 30 shown in FIG. Note that this ashing device 30 is similar to the ashing device 2 shown in FIG.
Therefore, instead of moving the wafer mounting table upward, a configuration is adopted in which the injection unit is moved 1F.

In FIG. 2, the ashing device 30 includes a processing chamber 20 and loader/unloader sections 23a and 2 disposed on both sides thereof.
3b and these loader/unloader ffl<23a, 2
Belt conveyance mechanisms 2'4a each installed inside 3b
, 24b.

Here, the loader/unloader section 23a and the belt conveyance mechanism 24a are the side that carries in the wafer, and the loader/unloader section 23b and the belt conveyance mechanism 241) are the side that carries out the ashed wafer. Either side may be used as the loading side or the loading side. Further, there may be only one loader/unloader section.

Although not shown, the belt conveyance mechanisms 24a, 2
A cartridge for storing wafers stacked at predetermined intervals is installed at the opposite end of 4b, and as the cartridge moves two degrees, unprocessed wafers are sequentially transferred from the cartridge to the belt. Mechanism 24a
is sent to the loader/unloader i<23 a. The ashed wafer is transferred to the loader/
The materials are sequentially stacked and stored in the cartridge from the unloader section 231) through the bell transport mechanism 241).

Now, the processing chamber 20 is made of, for example, SUS, AJ, or TiN.
The wafer mounting table 205 is provided with a chamber 29 coated with A, 2, etc., and a wafer mounting table 205 is installed at the center inside thereof. Then, at a predetermined interval, the gas injection unit 2221 moves 1-
It is supported on the ceiling side.

Here, the gas injection part 22a has a conical shape consisting of a disc-shaped diffusion plate 200 and a cone part 203 connected to the second part, and the cone part 203 has an ozone + oxygen gas introduction pipe. 202 is connected at a part thereof, and the introduction pipe 202 is connected to a metal bellows 20 made of SO8 or the like.
It is hermetically surrounded so that it can move up by 1, and seven waves of ozone and oxygen scum are introduced from this introduction pipe 202 into the reaction for ashing.

204 is a cooler for ozone + oxygen gas that spirally surrounds the outer circumference of the cone portion 203;
03 with heat conductive cement or the like. In the cooler 204, the refrigerant is introduced from the lower side of the cone portion 203, is discharged at the point of ζ, and is guided to the outside (14 times).

On the other hand, as shown in FIG. 4, the diffuser plate 200 has a slot 31 for blowing out fj gas, and uniformly distributes the cooled ozone and oxygen gas onto the wafer 28. It blows out onto the surface.

The diffuser plate 200 is supported at three points around its periphery by pole screw mechanisms 231, 232, and 233 at approximately 120° intervals, and is moved up and down.

It is driven by pole screw mechanisms 231, 232.
The gears formed on the ball parts 234, 235, and 238 (not shown in the figure) of the motor 233 are connected to the motor 23.
This is done by meshing with a worm gear carved into the rotating shaft 236 of the 0.

Note that the elevating mechanism for the injection part 22a is not a combination of such a motor, a ball screw, and a gear, but may be configured to directly move it up and down using an air cylinder or the like.

At the position shown in the figure, the injection ffi<22a is on the upper side 11. In this state (standby position), the wafer X28 is loaded into or unloaded from the wafer mounting table 205. - On the other hand, as shown in FIG. 4, the injection part 22a
When the wafer is lowered, the blowout of the diffuser plate 200 is spaced from the wafer surface by 0.5 to several millimeters, or about 10-odd millimeters (reaction position), and is positioned at the L part of the sea urchin/1 mounting table 205. , the gas is supplied to the surface of the wafer 28 on the wafer mounting table 205I-.

Note that a heating device 206 is installed inside the wafer mounting table 205 to heat the wafer mounting table 205. Further, in this example, in addition to the gas containing ozone, the chamber 29 also includes an IJ that affects the flow of gas from the diffusion plate 200, and N2 to cover it.
2 gases are introduced.

Now, 26a is a suction chuck part supported on the tip side of the transfer arm 25a, and loa is a suction chuck part 28 that moves up and down with respect to the main body of the suction chuck part 28a.
This is an electrostatic chuck supported by a. In the figure, wafer 2
8 is shown being attracted to the electrostatic chuck 1°a. In this case, the wafer may be attracted by negative pressure, or may be mechanically clamped or held.

The other end of the transfer arm 25a is fixed to a support 27a disposed in the loader/unloader section 23a, and the transfer arm 25a is a front-knob transfer mechanism type that moves back and forth between the loader/unloader section 23a and the wafer mounting table 205 of the processing chamber 2o. It is an arm. Note that this transfer arm 25a may be constructed of a magnetic cylinder, an air cylinder, or the like.

Here, the reason why the frog leg transport mechanism is used is that the transport mechanism section can be made smaller, and, for example, ashing processing chambers are provided on both sides of the loader/unloader section, so that the support 27a of the frog leg transport mechanism can be rotated. if,
Since the frog leg transport mechanism can be directed to the desired chamber side, there is an advantage that wafers can be selectively transported or unloaded to both chambers.

In addition, if a loader/unloader section is provided in a straight line between the belt transport mechanism and the chamber, and the support 27a is made rotatable, the wafer can be similarly picked up and rotated from the belt transport mechanism side, and then reversed. It is also possible to transport the device to the chamber side, and even in such a case, the entire device can be realized as a small II;41 device.

The loader/unloader section 23b is also provided with a similar frog-leg transfer mechanism-type transfer arm 25b, a suction chuck m528b, its electrostatic chuck 10b, and a support 27b in a symmetrical relationship. In addition, in the figure, the electrostatic chuck 10b includes a processed wafer 28.
is adsorbed.

Therefore, the wafer mounting table 205 is provided with a plurality of holes 220 for negative pressure suction. In addition, the wafer mounting table 2
Around the ring plate 222, a plurality of exhaust volumes 0219, 219, .
The ring plate 222 is fitted into the outer peripheral side of the wafer mounting table 205 at a position slightly lower than the two sides of the wafer mounting table 205.

221 and 223 are exhaust pipes that air the chamber 29 at 01°, and are connected to the 4 pumps of the υI° air system. Two or more exhaust pipes 221, 223 are provided so that the air is evenly distributed, but the number of exhaust pipes 221, 223 may be one. Further, 224 and 225 are gate valves, respectively.

Further, 226 and 227 respectively indicate the belt conveyance mechanism 24.
A and 24b are conveyor belts, and 217 and 218 are chambers of the loader/unloader sections 23a and 23b.

Here, this loader/unloader ff1s23a, 23b
The channels 217 and 218 may also be pumped up and evacuated according to the internal pressure of the chamber 29.

Next, to explain the operation of this device, 1 direct ray $2
It is assumed that 2a is set to 1, the raised state, held in the standby position, and the gas introduction valve R-1202 is closed.

When the gate valves 224 and 225 are closed, the pressure inside the chamber 201 is close to normal pressure and almost reduced to zero.

In addition, in the case where the utensil installation stand 21 shown in FIG. Yaku 1st place 21
There are many ways to lower it and set it to the standby position. However, the loader/unloader department's 1 father, 1 section &! This is similar to the case shown in FIG.

Now, in this state, with gate l<lub 224 open~), loader/unloader section ζ23 is
The Ueno 128 carried into a is placed in its static chuck 1.
0a is lowered, a voltage is applied to it, and the suction 7t chuck 28a attracts it. And this h'1 electric chuck 1
0a to L Yr- and pick up Ueno) 28. Next, the transport arm 25a is extended and the adsorbed sea urchins 1128 are transferred from the loader/unloader section 923a to the processing chamber 2.
The electrostatic chunk 10a is transferred to the zero position and positioned at the wafer 1 placement table 205 [-, and the electrostatic chunk 10a is moved to the ll5- mode, and the applied voltage is lowered and the wafer 28 is allowed to fall. The wafers are then placed on the wafer mounting table 205 by suctioning them with negative pressure on the side of the wafer mounting table 205.

Next, after raising the electrostatic chuck 10a, the transport arm 25a is contracted and the suction chuck 26a is returned to the loader/unloader section 23a. After the suction chuck 26a moves around the loader/unloader section, the gate valve 224
is closed, the injection parts 22 and 1 are lowered to the reaction position, and the diffusion plate 200 is set at the reaction position shown in FIG.

In the case of the ashing device 2 shown in FIG. 1, the wafer 28 is placed at the reaction position by moving the wafer mounting table 21 upwards from the upper portion 511 of the device 5.

Here, the temperature of the wafer 2B is monitored, and when it reaches a predetermined ashing processing temperature, the gas introduction II 202 is started.
The valve is opened, and ozone and oxygen gas are uniformly sprayed onto the surface of the wafer 28 placed on the wafer mounting table 205.

As a result, the resist on the wafer 28 is oxidized, and the gases generated by this chemical reaction, such as carbon dioxide, carbon oxide, and water, are passed through the υ1° trachea 221, 223 by the exhaust device 4 together with the oxygen after the reaction. υ1: Noticed.

When the ashing process is completed (for example, l min to several min), close the valve of the gas inlet 202 and move the diffusion plate 200 to the standby position (first
In the figure, the wafer mounting 205 is lowered to the standby position), the gate valve 225 is opened, and the transfer arm 25b is moved from the loader/unloader section 23b to the processing chamber 20.
Extend the holder 26b and place it on the wafer mounting table 20.
5, lower the electrostatic chuck 10b on the tip side, and apply a voltage to it. Then, the ashing-processed wafer 28 is adsorbed by the wafer mounting table 2051-, and the electrostatic chunk 10b is -17,! I'll let you ri', then I'll make a fuss. And electrostatic chuck 10aG,, LshiI
' After that, the transport arm 25b is contracted and the processed wafer 128 is transported to the loader/unloader jms 23b.

In this way the loader/unloader i? The wafer carried out to 23b is transferred from the loader/unloader section 23b to the belt conveyance mechanism 24b, and is stored in a cart and a flatbed, and the ashed wafer is taken out of the apparatus.

Here, the electrode portion of the electrostatic chuck will be explained. Note that in FIG. 1, the electrostatic chunk 10211tab has the same configuration, so in the following description, the electrostatic chunk 10 will be explained, and its electrode portion will be referred to as the electrostatic chuck electrode portion 17.

Now, as shown in FIGS. 3(a) and 3(b), the electrode part 17 of the electrostatic chuck IO for wafer suction is located inside the back surface.
- A first electrode 11.1 made of a conductor such as a disk-shaped metal, provided with circular depressions 11a and 12a, respectively;
2.

By the way, when automatically transporting a wafer, it is overwhelmingly often modified to suck the wafer from the front side and transport it part-time. Therefore, the electrode section 17 is attached as an electrostatic chuck in a state where it is suspended from a wafer transfer device so that its suction surface side faces downward.

Here, these first. The second electrode 11.12 is the insulating film 1
3.14, and are arranged at predetermined intervals. This gap 1) may be left as a void, or an insulator may be inserted depending on the structure. The selection may be determined based on the overall structure of the electrostatic chuck 10.

1st. As shown in FIG. 3(a), the second electrodes 11 and 12 have a substantially semicircular outer periphery with a radius R, leaving a portion of width W, and the inside is concave (depth h). The part W is the suction part 15.187 of the conductor wafer. Adsorption ff
The insulating film 1 is formed on each surface where l<15.16.
3.14, insulating films 15a and lea are provided as coated layers, and these insulating films 15a
, lea are determined based on the suction force of the wafer, etc. The thickness of the insulating films 13 and 14 other than this portion is determined in consideration of the fact that this electrode portion has sufficient breakdown voltage when it comes into contact with other metal portions.

Next, the ashing reaction will be explained in detail according to FIGS. 4, 5(a), and 6.

As shown in FIG. 4, in the ashing process, the ozone supplied from the ozone + oxygen gas supply device 3 enters the following thermal parallel state inside the injection section 22a (or the same applies below the injection section 22). It has become.

OJ:02+.

In this case, the lifetime of the oxygen atom radical 0 obtained by decomposing ozone depends on the temperature, and as shown in Figure 6, the lifespan of oxygen atom radical 0 is 25°
It becomes very long near C.

However, as the temperature rises, its lifespan rapidly shortens.

- On the other hand, the ashing process using oxygen atom radicals is an oxidation chemical reaction, which becomes faster at higher temperatures.

Moreover, it takes a certain amount of time for the oxygen atomic radicals to act on the wafer surface. So wafer 28
An important issue is how to efficiently continue to supply oxygen source r radicals to the surface of the substrate.

The ashing process proposed in this invention effectively supplies oxygen radicals to the surface of the wafer 28 and rapidly removes reaction products from the wafer surface. In the synergistic treatment with the supply of oxygen source r radicals, the ashing process can be increased to a processing speed suitable for single wafer processing.

Therefore, it is easy to create an appropriate gas flow space that supplies oxygen atomic radicals and removes reaction products.

In this embodiment, as shown in FIG.
00.

The distance between the wafer mounting table 205 and the diffusion plate 200 is relatively narrow, and if the wafer 28 is heated to a high degree of 7AJ, the distance between the wafer mounting table 205 and the diffusion plate 200 should be approximately 0.5 to several mm from the wafer surface. Is required. Further, the outermost opening position (the position of the slit 31a in FIG. 4) is determined so that the injected gas is blown outward by at least 5II1 m from the outer shape of the wafer 28.

By blowing the gas outward from the outer circumference of the wafer 28 in this way, a negative pressure area is formed by the gas flow on the outer side of the wafer periphery, and the generated gas from the center side is transported outward from the wafer periphery more quickly. , is something that is discharged.

As a result, it is possible to facilitate the supply of ozone and the contact of oxygen atom radicals to the wafer surface, thereby promoting the oxidation reaction.

Now, the ozone + oxygen cooled by the cooler 204 is
For example, it is cooled to about 25 to 50°C.

Therefore, the oxygen atom radicals are transferred to the cone part 20 of the injection part 22a.
3. The rate held internally increases.

As soon as ozone (03,02+O) and oxygen 02 are injected from the opening of the diffuser plate 200, they are exposed to a high z and l atmosphere, but before their lifespan ends, they reach the wafer surface together with oxygen. Ashing (ashing) the film deposited on the wafer surface.

that is, oxidized and removed from the wafer surface).

As shown in FIG. 5(a), carbon dioxide, -carbon oxide, and vaporized water generated by ashing rise simultaneously to form oxygen (02) and non-radical ozone (03) that are spouted out from the diffuser plate 200. Riding on the flow, it is removed from the surface, carried through the exhaust opening 219 of the ring plate 222 to the υF trachea 221, 223, and sequentially evacuated by the exhaust device 4.

Therefore, an environment can be created in which the surface of the wafer 28 is constantly exposed to oxygen atomic radicals.

In FIG. 5(a), 28a is the surface portion of the wafer 28, 28b is the portion of the resist adhered to the sea urchin I\28, and the arrow 32 is the ozone emitted from the diffusion plate 200. + Shows the flow of oxygen gas.

Here, the wafer temperature is set at 300°C, and the standard state at the opening of the diffuser plate 200 ( When measuring the ashing speed with respect to the gas flow rate under normal crystal conditions and normal pressure conditions, as shown in Fig.
In the range of s1 (Sλ: flow rate converted to normal temperature and normal pressure), particularly high-speed ashing processing is possible, and 40s/n+
It gradually becomes saturated from about In.

In order to make this flow rate correspond to a general wafer diameter, if we convert it to the flow rate per medium area of the wafer, it will be 0°01~
0.25'sJ! /min *an? becomes.

Furthermore, when the relationship between the ashing speed and the gap between the diffuser plate and the wafer surface is determined by fill using the gas flow 1i as a parameter at a wafer surface temperature of 300°C, as shown in Fig. 8, when the gap is 20 mm or more i-, Regardless of the gas injection flow rate, it exhibits a characteristic that converges toward a constant value.

Furthermore, regarding the relationship between the temperature of the gas ejected from the diffusion plate 200 and the resist removal rate, the gap to the wafer (the distance from the surface of the wafer 28 placed on the wafer mounting table 205 to the surface of the diffusion plate 200) 2111. When the reaction time is l min, and the characteristics are measured using the gas flow M as a parameter, as shown in Figure 9, it is found that it is difficult to remove the gas when the temperature is -1-glow at about 200 °C. It can be understood.

Therefore, when the reaction is carried out by heating the wafer side to 200° C. or higher, it is preferable to cool the injected gas (ozone + oxygen). As a particularly preferable range, the temperature of the outflow gas of the diffuser plate 200 is 15 to 50.
It is at ℃.

This can be seen in Figure 6, where ozone decomposition) ['.

This is consistent with the characteristics of a reduced sentence.

In addition, as shown in Figure 16, when we investigate the relationship between the ozone concentration and the ashing rate, we find that the ozone concentration is
As the ashing speed is increased, the ashing speed increases by f9+'. However, if the condition becomes 10 or more severe, the force shifts to saturation. Note that this characteristic is for a 6# wafer, the temperature is 250°C, and one gas flow is 5 s/min.
The resist was hardened by plasma irradiation in the etching process, and the IF force in the chamber was about 700 Torr.

As can be understood from the respective characteristic graphs, by forming a flowing gas space in a portion of the wafer and injecting or flowing gas containing ozone onto the wafer, the ashing process can be performed at several μm/min per portion. Becomes Noh. This realizes ashing suitable for single wafer processing and processing of large diameter wafers.

FIGS. 10(a) to 10(d) are explanatory diagrams of specific examples of a diffusion plate 200 that evenly injects ozonated oxygen gas onto the surface of a wafer.

In FIG. 10(a), four arcuate slits 311 are formed in a circular and concentric solid shape, and these grooves may be perpendicular to the east of the wafer, but there is no gas on the outside. Diagonal slots are used to allow gas to flow outward to form a flow.

In FIG. 10(b), a hole 312 is provided in the center of a circle, and slots 313 are arranged radially with respect to the hole 312. In FIG. 10(C), holes 314 are provided radially, and the name tag 314 becomes slightly more visible toward the outside. FIG. 10(d) shows a case where a sintered alloy 200a is used as a diffusion plate 200, and porous holes 31 are formed over the entire surface of the plate.
5 are uniformly C1.

In FIG. 10(e), the jet 1131B is formed in a spiral shape, and in FIG. 10(f), a small hole 317 is formed in a circular shape.

Here, in order to examine the effect of uniformly and uniformly outflowing gas from the diffusion plate 200, we will examine the case where holes are sparsely opened as shown in FIG. Comparing this with the case where the porous pores are uniformly distributed as shown in t), in the case of 1), as shown in FIG. 5 (1)), the lent portion 28b is Ashing occurs in response to the gas flow 32 (Amakawa), and the ashing becomes uneven with gentle waves.On the other hand, when porous pores are uniformly distributed as in the latter sintered alloy, As shown in FIG. 5(C), uniform ashing is performed.

Therefore, it is best to provide a gas injection port to make the gas more uniform.This has the advantage that the processing time until complete ashing can be shortened, and that the wafer 1 is not easily damaged even when ozone is applied to the wafer surface. be. In addition, in FIGS. 5(b) and 5(C), the portion indicated by the dotted line is the surface position (thickness) of the resist before ashing.

Now, as seen in the characteristic graphs in Figure 6, etc., gas (
It is better to inject ozone + oxygen from a diffuser plate in a state as cool as possible.

By the way, the distance between the wafer mounting table 205 and the diffusion plate 200 is relatively short. On the other hand, the wafer mounting table 205 and the wafer 28 are heated by the heating device 206 to the reaction temperature. Therefore, the diffusion plate 200 is heated by radiant heat emitted from the wafer mounting table 205 and the wafer 28 side, and the temperature of the surface of the diffusion plate 200 tends to rise.

As a result, the temperature of the gas is 11 Y'y'+ around 1 for injection.
' i of the oxygen atom radicals supplied to the wafer surface
'i1 will decrease. In particular, if the gear is large, the effect of heat will be somewhat reduced, but the time taken for the oxygen atom radicals to travel will be longer (so that the wafer temperature, including the effect of temperature - h') will be reduced.
The number of oxygen atom radicals whose lifetime ends before reaching the surface of 8 also increases. Also, if the gear knob is too small,
Directly affected by the temperature on the side of the wafer mounting table 205, the temperature 1゛511 on the surface of the diffuser plate 200 tends to be higher (111).Furthermore, the temperature 1゛511 on the surface of the diffuser plate 200 tends to be higher than that. ．The values also differ.

For this reason, there are more optimal conditions for ashing processing. In the reaction pattern shown in Figure 4,
When the wafer temperature is about 200°C to 350°C, the more optimal gap is about 1 to 3mm, and the gas flow rate is about 6# wafer at room temperature and normal pressure.
It is about 5.5 to 17 sJ/min. Therefore, this is a wafer? When converted to the flow h1 of the 11th surface area weight, it becomes cJ of 0.03 to 0°1 sJI/min.

In addition, carbon dioxide reacted by oxygen atom radicals, -
Considering that reaction products such as carbon oxide, water, etc. are carried away from the wafer surface by 1 submerged oxygen (02), there is a 111% weight of ozone and oxygen which is more efficient.

That is, if the amount of ozone (03) is low, the ashing rate (the rate of decrease in rll relative to the film thickness) will be low, the uniformity will be poor, and the efficiency will be poor. On the other hand, ozone (03
) is high (and oxygen (O2) is low), the rate increases, but stagnation of reaction products occurs on the wafer surface and the reaction rate slows down.

Taking these points into consideration, the optimal ozone IRj
i! For %, 3'T<Lt% to 5'n j
, l: about % is suitable.

Now, taking these matters into consideration, the Kure system of the cooling structure of the injection part, which injects gas at the lowest possible temperature as well as uniform gas injection, will be explained next.

The injection part 22b shown in FIG. 11(a) has a cooling pipe 204a made of a coiled pipe also arranged on the inner surface of the diffusion plate 200, and communicates with the cooler 204. This is arranged in a meandering manner while avoiding the slit 318 for this purpose.

In addition, the injection part 22b shown in FIG.
A cooling pipe 2 made of a coiled pipe is installed on the outer surface of the 00 (wafer 28 side).
04b is disposed and communicated with the cooler 204, and similarly follows the slit 318 in a meandering manner while avoiding the slit 318. In this case, the cooler 204 disposed around the cone i'l<203 in FIGS. 11(a) and 11(b) may not be provided.

By doing so, even if there is heat radiation from the wafer mounting table 205 side, the surface of the diffusion plate 200 can be suppressed to a low state, and the temperature of the injected gas can be suppressed to make it easier to It is possible to perform effective a/ing processing under condition F.

The injection part 22e seen in FIGS. 11(c) and 11(d) has a circle X1
It has a cylindrical shape rather than a cylindrical shape, and has a dome 22d for gas diffusion in a part, and after the gas is diffused in advance with this dome part, a diffusion plate 311 having slits or a sintered The bonded metal 200a is sent to the diffusion plate.

In particular, in FIG. 11(C), a serpentine cooling tube 204c is built into the cylindrical part, and in FIG.
b is filled inside. Incidentally, although these are not provided with a cooler on the outside, it goes without saying that a cooling pipe may be provided on the outside of the cylindrical portion as in FIGS. 11(a) and 11(b).

Next, an example will be described in which the wafer and the diffusion plate are rotated relative to each other in order to blow gas more uniformly onto the wafer surface and further promote the oxidation reaction.

The injection part 33 shown in FIG. 12(a) has a gas introduction pipe 35 that communicates with a diffusion pipe 34 at its center, and the gas introduction pipe 36 is rotatably supported on the ceiling side of the chamber 29. has been done.

Here, both ends of the diffusion tube 34 are closed, and the injection 1-136.38. ... are arranged at predetermined intervals. Furthermore, inject L' to the position opposite to the side surface of the end (the side facing east with the wafer surface) with your back turned to the side surface.
+37.38 is provided, and when gas is injected from there, the diffusion tube 34 rotates by itself due to the reaction. Moreover, the gas injected from both ends of the wafer 28
It is located outside the outer periphery of the camera and also plays the role of continuously photographing the asoning products outward. Note that instead of injection n 36,
A porous material may be used for the surface of the diffusion tube 34.

In the example shown in FIG. 12(b), the wafer mounting table 205 is supported by a shaft, this shaft is pivotally supported on the floor side of the chamber 29, and the wafer mounting table 205 is rotated by a motor. It is. In addition, the injection part 22a is shown in FIG.
) or rod-shaped.

Comparing the effects of using and not using such a rotation operation, we found that when using the rotation method,
The processing time during which the resist on the wafer is removed is reduced. In other words, if we compare this with the same process as the rotation method, 11, and the case where the wafer is not rotated, as shown in FIG.
Although the resist is divided by υ1, there is a phenomenon in which the remaining 4° of the resist is not removed and remains as a striped pattern around it. Note that this was done for a 6# wafer.

For this reason, the rotation process is effective in shortening the ashing process time, and can be said to be effective in ashing the peripheral area of the wafer except for the central area. In particular, it is effective for 1 diameter wafers for people with sizes 6# to 1o''.
In this case, since the gas injection part automatically rotates, there is an advantage that the device becomes intermediately pure, or it is necessary to inject a large amount of gas. On the other hand, in the case of FIG. 12(b),
Although the apparatus is somewhat complicated because the wafer mounting table 205 side is rotated, it has the advantage that the amount of gas to be injected is small.

Next, the end detection of the ashing device, which is related to the overall control when performing single wafer processing, will be described.

As shown in Figure 14, the end r of the ashing device is ↑J
A gas analyzer 7 is installed in the F gas equipment 4.

Then, carbon dioxide (CO2) obtained from the gas analyzer 7 is
) The detection signal corresponding to the concentration is manually input to the end point judgment/control device 8 to monitor the concentration of carbon dioxide, and when this concentration becomes zero or less than a predetermined value, the processing is completed. It is determined that it is a thing.

Here, the end point determination/control device 8 has an internal comparator, a microprocessor, and a controller composed of a sensor. Sourcing device 2. Gas introduction, the gas valve of the N6 pipe (see gas introduction pipe 202 in Figure 2) and the lowering device 5 (
In FIG. 2, a motor 230) is controlled.

That is, when the end point is detected, a signal is generated to close the valve of the gas introduction nozzle, and the gas injection is controlled to be stopped. Is this poor and 5 at the same time? A wafer mounting table 2 is placed on the unloading device 5.
By sending out the conical bow of 1 and controlling this, the gap between the diffuser plate and the urchin/1 mounting table is filled (and the urchin 1 mounting table (in the embodiment shown in Fig. 2) is , injection unit) to the standby position.

η1 - Received standby position setting signal from unloading device 5 11.
At point +i, the end point determination/control device 8 connects the loader/unloader unit on the wafer unloading side (loader/unloader ff in FIG.
A control signal -j is sent to the ashing device 2 to open a gate valve (gate valve 225 in FIG. 2) communicating with the ashing device (see i<23b). The unloading device 2, which has received this success, opens its gate valve and communicates the chamber (chamber 29 (D) in FIG. 2) with the loader/unloader section on the wafer unloading side.

Next, the end point determination/control device 8 sends a signal to the ashing device 2 to operate the unloading side wafer handling mechanism (transfer arm 25b in FIG. 2).

Upon receiving this signal, the ashing device 2
At the same time, the UNO X28 on the wafer mounting table 21 (see wafer mounting table 205 in Figure 2) is pink-amplified and removed from the chamber. Then, the wafer is transferred to a belt conveyance mechanism (see belt conveyance mechanism 24b in FIG. 2).

On the other hand, when the wafer handling mechanism on the unloading side completes unloading of the wafer from the chamber, the ashing device 2 sends a completion signal to the end point determination/control device 8. At the time of receiving this completion signal, the end point determination/control device 8 sends a control signal-J to close the gate valve (gate valve 225) communicating with the loader/unloader section on the unloading side of the sea urchin/1. The wafer is delivered to the ashing device 2, and its knob is closed to disconnect the loader/unloader of the wafer unloader 1. Next, the loader/unloader section on the wafer loading side (see loader/unloader 1 section 23a in FIG.
Valve communicating with (1) (valve 224 in Figure 2)
A control signal for releasing the ashing device 2 is sent to the ashing device 2.

The ashing device 2 opens its valve and communicates the chamber with the loader/unloader section.

Next, the end point determination/control device 8 sends a signal to the ashing device 2 to operate the carry-in side sea urchin/h handling mechanism (transfer arm 25a in FIG. 2).

The ashing device 2 operates the carrying-side Ueno 1 No. 1 handling mechanism, picks up Ueno The wafer 1 is placed on the wafer mounting table 21 (wafer mounting table 205).

Then, the wafer mounting table 21 attracts and holds this.

Wafer loading side r of the wafer handling mechanism on the loading side
When the ashing device 2 completes and the arm etc. returns to the loader/unloader, the end point determination/control device 8
Send a delivery completion message to.

Upon receiving this signal 5, the end point determination/control device 8 sends a control valve to the ashing device 2 that closes the valve communicating with the loader/unloader section on the wafer loading side, and also sends a control valve to the ashing device 2. Place the sea urchin/X mounting table 21 on the unloading device 5.
The rising signal (in FIG. 2, the falling signal (ci) of the injection unit 22) is sent out.

Upon receiving the control signal to close the valve, the ashing device 2 closes the valve and closes the channel and the loader/loader on the loading side.
Separate from the unloader section. On the other hand, the wafer mounting table 21, which has been given the title, controls the wafer mounting table 21 and sets the gear between the diffusion plate and the wafer mounting table to the gap required for the reaction. (set to reaction position).

Ke11. 11, which received a reaction position setting signal from the descending device 5;
At point 5, the end point determination/control device 8 generates a signal to open the gas introduction/X'l valve and controls the start of gas injection. Then, exhaust gas is monitored and end point determination processing begins.

Figure 15 shows υ1 in this case. It is a graph showing the C degree change of carbon dioxide in air gas.

As shown in the figure, as the ashing process time progresses, the degree of carbon dioxide gradually increases until it reaches a constant value, and the temperature of the gear, tube and gas flow 1 in the oxidation reaction space, and the gas flow 1 are in the optimum range. Under conditions of It rapidly approaches zero.

Therefore, the end point of the ashing process can be determined by using a comparator to compare and detect the carbon dioxide concentration based on ff and lj based on a constant value of zero or close to zero.

By the way, the detected gas for the final determination is not limited to carbon dioxide, but water and carbon oxide have almost similar characteristics. Therefore, the end point of the ashing process may be determined by measuring the amount of gas.

On the other hand, as seen in this graph, the tendency of the gas generation to start decreasing from a constant value and then reaching zero has almost the same characteristics in the case of υ1゛ gas. Therefore, the point A where this characteristic changes or the point B where it decreases below a certain value
By detecting , the final point r can be measured as f.

The decreased point B can be detected by changing the quasi-values of the comparators, and the p survey path γ point can be easily determined by adding a fixed time to this detection point. .

Further, the detection of the change point A can be realized during a song by combining a differential circuit or a peak detection circuit with a comparator.

By the way, when detecting that Bl of tJl gas is less than a predetermined value, gas analysis 1.17 shown in FIG.
The determination unit of the end point determination/control device 8 includes a detector (gas sensor) that detects a specific gas [crosspiece] at a specific value or a specific range, and an end point determination circuit that determines the end point from the detection signal. (judgment processing using a comparator, a single logic circuit, or a microbrosé/zosa) is sufficient. on the other hand,
When detecting the change point of υI gas, use a +i I/ull device, sensor, or only the change state to generate +i I/ull device, a sensor, or a sensor 7+ that corresponds to i, 1-1j of a specific gas. A sensor is required.

1. As explained above, in the embodiment, the diffusion plate is placed at the 1st position of the wafer;
- In a suspended configuration, a configuration may be adopted in which gas is blown upward from the diffuser plate side or from the door. It may also be placed in the same position.

'Unfortunately, these placement relationships are not limited to upper C; It is enough to play A and face each other.

Moreover, any handling mechanism may be used to carry the wafer into and out of the annong apparatus, and it is needless to say that the present invention is not limited to the embodiment.

In the embodiment, in order to carry in the sea urchin/X, either the sea urchin/X mounting table or the diffusion plate is relatively moved to secure insertion space for the handling arm.

However, they may also move upward at the same time.

Furthermore, if a configuration is adopted in which the wafer is sent to the wafer mounting table using a belt transfer mechanism and a pu-nonya, etc., the diffusion plate and the wafer 1. The distance from the mounting table may be narrow, and the expanded space into which the handling arm etc. enter will become unnecessarily foggy.
A one-way movement mechanism for the wafer mounting table or the diffusion plate is not essential.

In the example, a case is described in which gas is injected, but in this case, it is sufficient that only the ozone + oxygen gas flows into the reaction space (11). Therefore, it is sufficient that the gas only flows out into the reaction space.

In addition, in the embodiment, the structure of the injection part is conical 2
A circular shape and a tubular shape are listed, but for example, a disk-shaped shape or a nozzle-like device may be used to inject or flow out raw ozone gas (various shapes are also available). The following are applicable.

Therefore, in this specification, the deck section includes a rod-shaped object whose locus forms an even flow of gas with the plate by rotating it.

The condenser may be adopted depending on the reaction conditions, and is not necessarily necessary. In addition, the structure is based on the case where the refrigerant flows through the pipe, but it is also possible to provide a double-structured space where the refrigerant flows directly into the injection part, and various liquids and gases such as water and cooling air can be used. Furthermore, cooling may be performed using a cooling metal or the like utilizing the Beltier effect or the like.

The diffusion plate is an example of using a sintered alloy as having uniform porous pores, and porous materials are not limited to metals, and various materials such as ceramics can be used. Of course.

Furthermore, l! of the wafer during the ashing process. ++
The higher the value, the faster the oxidation reaction rate will be, but this is also related to the wafer loading/unloading speed, and does not necessarily have to be set to a high value. moreover,
Considering the lifetime of ozone, the reaction can be carried out at room temperature or higher. In addition, ozone
If it is possible to set the hair ratio to a high value, it is possible even at a temperature even lower than room temperature. However, with current equipment, it is thought that the limit of ozone generation m:J% is around 10 to 13%.

In the examples, the description focuses on Lennost as the target for ashing, but as mentioned in the prior art, such ashing processing can be applied to various things such as removing ink and solvents, and can be used to remove oxidation. It may be anything that can be removed by doing so.

In addition, when ozone is mixed with oxygen gas for three times, gases such as C or oxygen that do not react with ozone, especially N2. It is possible to use various inert gases such as Ar, Ne, etc. with three strokes of ozone.

[Effects of the Invention] As can be understood from the explanation given below, in this invention, for example, an ozone outflow portion is provided at a position facing the wafer at a predetermined interval to prevent ozone from flowing between the wafer and the wafer. +By forming an oxygen gas flow space and setting the ozone content in the range of 3% to 5%, new ozone can be efficiently supplied to the wafer. , Oxygen Is'
Carbon dioxide, -carbon oxide, and ice/snow produced after the reaction by non-Cal oxygen (02) can be moved from the wafer surface in a vaporized state and emitted υ1.

As a result, the reaction surface of the film 9 deposited on the wafer 1-, for example, 6 films, can be efficiently exposed to the oxygen radicals, which have a very strong oxidizing action. .

Therefore, it is possible to perform high-speed annotation processing, and it is possible to realize an annotation apparatus suitable for single-wafer processing.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an adjustment processing system according to an embodiment of the invention, to which the adjustment device of the present invention is applied.
3(a) and 3(a) are cross-sectional explanatory views showing the overall structure of another similar embodiment, including the wafer transport mechanism.
b) is a specific explanatory diagram of the electrostatic charger in the wafer transport mechanism, (a) is a cross-sectional view taken along line II in (b) of the same figure, (b) is a 14th diagram thereof, Figure 4 is an enlarged explanatory diagram of the reaction part, Figure 5 (a) is a diagram explaining the relationship between the reaction and migration of the oxygen source ylancar, and Figures 5 (b) and (c) are respectively FIG. 6, which is a diagram illustrating the relationship between the diffusion amount 11 and the unwinding state of the wafer, is a graph illustrating the relationship between the decomposition half-life of ozone and the temperature of the diffusion amount [-1 part]. Furthermore, FIG. 7 is a graph explaining the relationship between the ashing rate and the gas flow nV at a wafer surface temperature of 300°C, and FIG. Figure 9 is a graph explaining the relationship between ashing speed and gap. r4
An explanatory diagram showing the relationship between degree and lens removal rate, Fig. 10 (
a), (b), (c), (d), (e), and (f) are explanatory diagrams of specific examples of diffusion plates 11 and 1, respectively, and Fig. 11 (
a), (b), and (cL (d) are explanatory diagrams of specific examples of the gas cooling structure in the injection part, respectively, and Fig. 12 (a)
) is an explanatory diagram of the method of rotating the gas injection unit, FIG. 12(b) is an explanatory diagram of the method of rotating the wafer side, and FIG.
An explanatory diagram of the ashing effect in the case of no rotation, FIG. 14 is a block diagram of an embodiment of the ashing processing system l that determines the end of the ashing process, and FIG. 15 shows the concentration of carbon monoxide in the exhaust gas. Graph of change, 1st
FIG. 6 is a graph illustrating the relationship between ashing speed and ozone concentration, and FIG. 17 is a diagram illustrating a conventional ashing device using ultraviolet rays. 1... Ashing system, 2.20... A song device, 3... Oxygen gas supply device, 3a... Gas flow rate regulator, 3b... Ozone generator,
3c...Oxygen supply source, 4...υ1 air device, 5...
Lifting device, 6... Temperature controller, 7... Gas analysis 1'
il'% 8...End point determination/control device, 10a, 10
b... Electrostatic chuck, 21... Wafer mounting table, 21a, 206... Heating device, 22.22a, 22b-... Gas injection unit, 23a, 23
b...Loader/unloader section, 24a, 24b...
Belt conveyance mechanism section, 25a, 25b...transfer arm, 26a, 26b...suction chuck, 28...urchin 1-131...slip note. 111 Applicant Tokyo Electron Ltd. Figure 3) 2 (it l 1a 12a Figure 4 Figure 5) 1 Fake (0C) Figure 10 Figure 11 2 (C) (d) Figure 12 (CI) (b) Figure 17 Figure 13::; 1523 Figure 16 Go

Claims (8)

[Claims] (1) A flow space in which a gas containing ozone flows is provided in contact with the wafer, and the film deposited on the wafer surface is oxidized and removed, and the ozone content is between 3% and 5% by weight. An ashing device characterized in that the ashing device is in a range of % by weight. (2) The flow space is formed by arranging an outflow part from which a gas containing ozone flows out facing the wafer at a predetermined distance from the wafer.
The ashing device described in section. (3) The outflow portion has a flat plate portion, and the flat plate portion is provided with an opening for allowing the gas to flow out almost uniformly onto the wafer surface. The ashing device according to item 2. (4) The ashing device according to claim 2, wherein the flat plate portion is formed as a locus of a tubular member horizontally rotated. (5) The ashing apparatus according to any one of claims 2 to 4, wherein the wafer is heated. (6) The facing arrangement is characterized in that the outflow portion is on top, the temperature of the gas to be cooled is in the range of 15 to 50°C, and the heating temperature of the wafer is in the range of 150 to 500°C. The ashing device according to scope 5. (7) Claims 3 to 6, characterized in that the flat plate portion is made of a porous material and is disposed above the wafer, and the openings are pores of the porous material. The ashing device according to any one of the above. (8) The ashing device according to claim 7, wherein at least one of the wafer and the outflow portion moves up and down.