JPS62165926A - Ashing system - Google Patents

Abstract

PURPOSE:To ash and remove a film adhered on the surface of a wafer by forming a drift space for a gas containing O3, brought into contact with a wafer and cooling and flowing out the gas. CONSTITUTION:A gas outflow section 22 is shaped oppositely facing to each other at a set interval to a wafer 28, and a gas is cooled by a cooler. O2 is fed and O3 is generated, a flow rate is controlled and O3<+>O2 are cooled, and O3+O2 are fed continuously onto the wafer 28 controlled 6 at 150-500 deg.C. A reaction product gas generated is moved and discharged 4 from the surface of the wafer. At least one of the wafer and the gas outflow section 22 can be elevated by a device 5. Accordingly, the surface of an organic film on the wafer is exposed effectively to O radicals having an extremely strong oxidative effect, and can be ashed and treated at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ashing method (J-Daika method) for removing a film deposited on a wafer (1-1) using ozone. The present invention relates to an ashing method suitable for single-wafer processing in which a photoresist film (hereinafter referred to as resist) is removed by oxidation.

[Prior Art] Formation of fine patterns in semiconductor integrated circuits is generally carried out by etching a base film formed on a wafer I using a resist film of an irradiated polymer formed by exposure and development as a mask. It will be done.

Therefore, there is a risk that the resist film used as a mask will be removed from the surface of the wafer after the etching process. In such a case, an ashing process 11' is performed to remove the resist.

This ashing process is 7 strinoping.

It is also used to remove ink, remove solvent residue, etc. from the 2nd zero of silicon wafers and masks, and is suitable for dry cleaning in the 1-conductor process.

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

In resist ashing 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 atomic radicals remove the resist, which is an abrasive material. It utilizes the effect of oxidation, decomposition into carbon dioxide, carbon oxide and water, and vaporization.

However, in the ashing process using oxygen-resistant plasma as described in +)ij, the wafer is irradiated with ions and electrons accelerated by the electric field existing in the plasma, which adversely affects the electrical characteristics of the conductor integrated circuit. I-J, there is a drawback that it gets worse.

To avoid such drawbacks, UV light (
There is a device that generates radicals in the oxygen layer by irradiating UV) with j(() and performs ashing treatment by punching.In this type of device, compared to plasma treatment, the element r. This has the advantage of allowing efficient stripping and cleaning without damaging the elements.

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

A large number of wafers 101.101ees are placed in the processing chamber lOO.
are arranged vertically at predetermined intervals, and ultraviolet rays from an ultraviolet light emitting tube 103 installed at the top of the processing chamber 100 are irradiated through a transparent window 102 made of quartz or the like provided at the top of the processing chamber 100. Then, the oxygen filled in the processing chamber 100 is excited to generate ozone. Oxygen atom radicals generated from this ozone atmosphere are then applied to the wafer 101 to perform an ashing process.

Incidentally, in recent years, there has been a tendency for wafers to become smaller in size, and in line with this trend, single-wafer processing methods for processing wafers one by one are becoming common.

[Problems to be Solved] The above-mentioned ashing process using ultraviolet irradiation has the advantage of not causing damage to the wafer, but has the disadvantage that it takes time because it is a batch process. Moreover, since the process is performed in an ozone atmosphere, the resist ashing speed is only about 500 to 1,500 people/min.

However, in processing wafers suitable for the diameter of 1-1 people, the processing speed is usually 1 μm to 2 μm/mi.
The conventional equipment for irradiating ultraviolet rays cannot handle single wafer processing in 1 minute.

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

[Purpose of the Invention] The present invention has been made in view of the problems of the prior art. The second objective is to provide an ashing method that does not require the use of ultraviolet light.

[Means for Solving the Problems] The means of the ashing method of the present invention for achieving such objects is to provide a flow space in contact with the wafer through which a gas containing ozone flows, and to cover the wafer surface. This method oxidizes and removes the film that has been heated at RT, and the gas is cooled and discharged first.

[Operations] For example, an ozone outlet is provided at a position facing the wafer at a predetermined distance to form a flow space for cooled ozone + oxygen gas between the wafer and the wafer, thereby introducing fresh ozone to the wafer. Continue to supply.

This promotes the oxidation chemical reaction between the oxygen atomic radicals and the film deposited on the wafer, and the carbon dioxide produced after the reaction by non-radical oxygen (02).
- Carbon oxide, water, etc. can be moved from the wafer surface in a vaporized state and emitted from the wafer surface.

As a result, a wave appears on the wafer 1 against the oxygen source R-Rankal, which has an extremely strong oxidizing effect. The reactive surface of the treated membrane 9, for example, any membrane, can be efficiently exposed to oxygen rays -r radicals.

Therefore, it is possible to perform high-speed asonon processing ii)
This makes it possible to realize an ashing device 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 unsong method of the present invention is applied, and FIG.
Another similar embodiment is shown in FIGS. 3(a) and 3(b).
2 is a concrete explanatory diagram of the electrostatic chuck in the wafer transfer mechanism, in which (a) is a sectional view taken along line II in FIG. The figure is an enlarged explanatory diagram of the reaction part, Figure 5 (a) is a diagram explaining the relationship between the reaction and movement by the oxygen source r radical, and Figures 5 (b) and (C) are the amount of diffusion, respectively. Figure 6, which is a diagram explaining the relationship between II and the anodizing state in the wafer, shows ozone decomposition "l': b5 !u! and diffusion 1) old-1 part 1.
,．． It is a graph explaining the relationship with 1 degree.

In addition, FIG. 7 shows the wafer surface 1ful I hole 300
Figure 8 is a graph explaining the relationship between the annosong velocity and the gas flow (,1) at the wafer surface tKL.
Figure 9 is a graph explaining the relationship between the ashing device and the gear knob between the diffusion plate and the wafer surface at 300°C, and Figure 1O (a), ( b), (c), and (d) are explanatory diagrams of specific examples of the diffusion plate space 11, and FIG. 11(a),
(b), (c), and (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 part, Fig. 12 ()))
is an explanatory diagram of rotating the wafer side, FIG. 13 is an explanatory diagram of the ashing effect when the wafer side is not rotated, and FIG. 14 is an explanatory diagram of an embodiment of the ashing processing system for determining the end of the anno-7ing state. Figure 15 is a graph of changes in the concentration of carbon monoxide in the ill gas, Figure 16.
The figure is a graph illustrating the relationship between anosong speed and ozone concentration.

In FIG. 1, ■ is an ashing processing system, which includes an ashing device 2, an ozone + oxygen gas supply device 3 that supplies oxygen gas containing ozone to the ashing device 2, and an exhaust gas connected to the ashing device 2. The wafer mounting table 21 placed inside the device 4 and the ashing device 2 is
- 5'i' of the wafer is moved by adjusting the heating state of the unloading device 5 and the heating device 2La installed in the wafer mounting table 21 to move the wafer i'! It is equipped with a temperature regulator 6 that controls the temperature at 11 degrees.

The ozone + oxygen gas supply device 3 includes a gas flow: 11° regulator 3a, an ozone generator 31), and an oxygen supply at 30
The ozone concentration, gas ML id, and gas pressure in the ashing device 2 (processing chamber) are determined based on these gas flows;
It is adjusted by the relationship between the 11 regulator 32L, the ozone generator Z43b, the oxygen supply source 3c, and the 1/1 gas device 4.

The ozone concentration supplied to the ashing device 2 is adjusted by the ozone generator 3b and set to a predetermined value.

Further, the wafer mounting table 21 arranged inside the ashing device 2 holds the wafer 28 by suction, and the 7! ,,1 degree is maintained at a predetermined value by 1I11+L degree adjustment 6.

One part of the wafer 28 has a distance of 0.5 to 20 m from its surface.
Cone-shaped injection parts 22 are provided to inject ozone + oxygen gas at intervals of approximately 1 m.
) The interval shown in item 11 is 1-! ri', it is set to a predetermined value. In this case, the injection section 22 side may be driven by the lowering device 1'.

Injection) ■ 22 is made of SUS (stainless steel) or Aλ゛9, and has a disc-shaped diffusion plate portion 2 that forms the surface of the wafer 28 and the middle 11 on the surface facing the wafer 28.
What are you doing with 2a? In order to carry in and take out the wafer 28, the wafer 28 is lowered by the wafer mounting table 21 or the wafer 11 unloading device 5, and the space between the expansion plate 22 and the wafer 28 is enlarged. This is performed when the wafer transport machine +1η art enters.

Now, for the ashing process, the wafer mounting table 21'',
This is done by heating the wafer 28 to a temperature in the range of about 150°C to 500'C, in particular, to a specific value of 200'C to 350°C, and the ozone and oxygen generated by the ozone are mixed.
The mixing ratio is adjusted by ozone generation KV 3 c. And oxygen gas containing this ozone.

For example, 31-15. ! '/min into the chamber of the ashing device 2, which is a processing chamber. That person at this time/
The gas pressure inside the blowfish device 2 is, for example, 700 to 200 To
Set it to a range of about rr.

Next, handling 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 differs from the ashing device 2 shown in FIG. 1 in that the wafer mounting table is moved one step, but the ejection unit is moved one step.

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 belt conveyance mechanisms 24a and 24b installed inside these loader/unloader sections 23a and 23b, respectively.
It is composed of.

Here, the loader/unrotor section 23a and the belt transport mechanism 24a are the side that carries in the wafer, and the loader/unloader section 23b and the side belt transporter 24b are the side that carries out the ashed wafer. Either side may be 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 by moving this cartridge by -1-degree, the wafer before processing is removed from the cartridge. Sequential belt conveyance mechanism 2
4a to the loader/unloader section 23a. The wafer that has been subjected to anothing is then transferred to the loader/
From the unloader section 23b, the sheets are sequentially stacked and stored in the cart via the belt conveyance mechanism 24b.

Now, the processing chamber 20 is made of, for example, SUS, Aλ, or TIN.
It has 12 chambers 29 coated with A, etc., and a wafer mounting table 205 is installed at the center of the inside thereof. A gas injection section 22a is supported on one large side of the chamber 29 at a predetermined interval so as to be movable in one direction.

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 L thereof, and the cone part 203 has an ozone + oxygen gas introduction pipe 202. The introduction pipe 202 is hermetically surrounded by a metal bellows 201 made of SUS or the like, and the reaction for ashing is connected to the introduction pipe 202. Seven waves of ozone + oxygen gas are introduced.

204 is a cooler for the ozone + oxygen gas that accumulates in a spiral shape around the outer circumference of the cone portion 203;
It is fixed by thermally conductive cement at n<203. The cooler 204 uses the refrigerant in the cone portion 2.
Nine people are ejected from the do side of 03, discharged at the IJ'1 point, and guided to the outside.

On the other hand, as shown in FIG. 4, the diffusion plate 200 has a slit 7 (lfll-1) 31 for blowing out gas, and uniformly distributes the cooled ozone + oxygen gas onto the wafer 28. Blows out onto the surface.

The diffuser plate 200 has J,', approximately 12 on one side.
Pole screw mechanism 231, 232.2 at 0° intervals
33, it is supported at three points and moves -1-degree.

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.
It is rotated by meshing with a worm gear carved on the rotating shaft 236 of 0.

Note that injection m<22a! The M' lowering mechanism may not be a combination of such a motor, a ball screw, and a gear, but may be configured to directly move it from 1 to 1 using an air 7 ring or the like.

And, at the small position in the figure, the injection ffl<22 a
h) I゛.

! The wafer 28 is in the r11 state (standby (1 purchase i"1:) and is in a relationship where the wafer 28 is loaded into or unloaded from the wafer mounting table 205. On the other hand, as shown in FIG. 4, the injection unit 22a If it falls, the blowout of the diffuser plate 200 may be 0.5 to several mm or more than 10 mm from the wafer surface.
The wafer mounting table 205 is positioned at the 1- part of the wafer mounting table 205, and gas is supplied to the surface of the wafer 28 on the wafer mounting table 2051-.

Note that a heating device 206 is installed inside the wafer mounting table 205 to heat the wafer mounting table 205. In this example, in addition to the ozone-containing gas, N2 gas is introduced into the chamber 29 so as to cover the gas flow from the diffusion plate 200 without affecting it. ing.

Now, 26a is a suction chuck part supported on the tip side of the transfer arm 25a, and 10a is a suction chuck part 71.
1: This is an electrostatic chuck supported by the suction chunk part 26a that moves upward relative to the main body of the recessed part 26a. The figure shows a state in which the wafer 28 is attracted to the electrostatic chuck lOa. In this case, the wafer may be attracted by negative pressure, or may be mechanically held at 1.1 N or more.

The transfer arm 25a has its other end fixed to a support 27a disposed within the loader/unloader section 23a, and moves back and forth between the loader/unloader section 23a and the wafer mounting table 205 of the processing chamber 20. It is a frog leg transport mechanism type arm. Note that this transfer arm 25a may be constructed of a magnetic cylinder, an air cylinder, or the like.

Here, the use of the freon bleb transport mechanism is because the transport mechanism can be made smaller and, for example, ashing processing chambers are provided on both sides of the loader/unloader section to make the support 27a of the freon bleb transport mechanism rotatable. Ba,
Since the freon bleb transfer mechanism can be directed to the desired chamber side, there is an advantage that wafers can be selectively transferred or unloaded to both chambers.

Furthermore, if a loader/unloader section is provided in a straight line between the belt transport mechanism and the chamber, and its support 27a is made capable of simultaneous rotation 1-iJ, wafers can be similarly picked up and amplified from the belt transport mechanism side. It is also possible to invert and transport it to the chamber side, and even in such a case, the entire device can be kept small! ';'It can be realized as an I thing.

Now, the loader/unloader section 23b is also provided with a similar frog leg transfer mechanism-type transfer arm 25b, a suction chuck section 26b, its electrostatic chunk 10b, and a support 27b in a symmetrical relationship. In the figure, a processed wafer 28 is sucked into the electrostatic chuck 10b.

Therefore, the wafer mounting table 205 is provided with several N holes 220 for negative pressure suction. In addition, the wafer mounting table 2
05, a plurality of exhaust volumes 1'1219. 219... is provided on a ring plate 222, and this ring plate 222 is fitted into the outer peripheral side of the wafer mounting table 205 at a position slightly more than 1° from the wafer mounting table 205.

221 and 223 are exhaust pipes for exhausting the chamber 29, and are connected to the pump of the exhaust device 4. Two or more exhaust pipes 221 and 223 are provided so that υI and air are evenly carried out, but the number of exhaust pipes 221 and 223 may be one. Further, 224 and 225 are gate valves, respectively.

Further, 22E3 and 227 respectively indicate the belt conveyance mechanism 2.
4a and 24b are the conveyor belts, and 217° and 218 are
This is a chamber of the loader/unloader sections 23a and 23b. Here, what about the loader/unloader sections 23a and 23b? The 7-bars 217 and 218 may also be evacuated by 1° according to the internal pressure of the chamber 29 using an empty pump.

Next, to explain the operation of this device, the injection 1 tB
22a is set to the upper gear 1-state and held at the standby position, and the valve of the gas introduction IN 202 is closed.

When the gate valves 224 and 225 are closed, the inside of the chamber 201 is in a carpet-like shape similar to that of an ordinary moon.

In the case of lowering the wafer installation table 21 h' in FIG. 1, the lowering device 5 is driven to lower the wafer installation table 21 and set it at the standby position. However, the rotor/unloader relationship is similar to that seen in FIG.

Now, in this state, the gate valve 224 is opened, and the electrostatic chunk loa of the wafer 28 carried from the belt conveyance mechanism 24a to the loader/unloader section 23a is lowered, and a voltage is applied thereto to cause the suction chuck 28a to drop. It absorbs 7t. And this electrostatic chuck 10a is -1-yj
' and pick up the wafer 28. Next, the transfer arm 25a is extended, and the attracted wafer 28 is transferred from the loader/unloader section 23a to the processing chamber 20, positioned on the wafer mounting table 2051-, and the electrostatic chunk 10a is lowered, and the applied voltage is is set to low or zero, and the wafer 28 is dropped from 1:p'. Then, the wafer is placed on the wafer mounting table 205) by applying negative pressure to the wafer mounting table 205.

Next, the electrostatic chuck loa is set to 1. After making t j+',
Reduce the transport element 1, 25a and move it to suction 7 (cha 26a
to the loader/unrotor ffl<23a. I.J.
)Jlj't+Yari 26H1 has moved to the loader/unloader section, close the gate valve 224, lower the injection section 22a to the window position, and the reaction shown in Fig. 4 ()"/ ', i+'+, i: Set the number of spreads to 200.

In addition, in the case of the 7-ring device 2 shown in FIG. 1, the wafer mounting table 21 is set at 1, and the wafer mounting table 28 is set at the reaction position by moving the wafer mounting table 21 at 1. .

Here, /+,, of the wafer 28, 1 degree is 1.4, and when the predetermined ashing processing temperature is reached, the valve of the gas introduction IN 202 is immediately opened, and the wafer 111! Ozone+oxygen gas is evenly sprayed onto the surface of the Ueno X28 placed on the Li stand 205.

As a result, the resist of Ueno
According to 1 no 1. The air is blown out through the trachea 221 and 223.

A. When song processing is completed (e.g. l min ~ f
fXmfn), close the valve of gas introduction 1-1202, and move the diffusion plate 200 to the standby position l-h' (first
In the figure, the wafer mounting number 205 is lowered to the standby position A), the gate valve 225 is opened, and the transfer arm 251) is extended from the loader/unloader section 23b to the processing chamber 20. The suction chuck 261) is moved to the wafer mounting table 2051-, and the electrostatic chuck lOb on the tip side thereof is lowered to apply a voltage thereto. Then, the ashed wafer 28 is placed on the wafer mounting table 205.
Adsorb it with H and make the electrostatic chunk 10b move by 1 inch, turning it pink. And the electrostatic charge loa is L'j+
After that, the transfer arm 251) is contracted and the processed wafer 28 is transferred to the loader/unloader: M<231).

The wafers thus transferred to the rotor/unloader section 23b are passed from the rotor/unloader section 231) to the belt conveyance mechanism 24b, and stored in a cartridge, where they are subjected to the anno/puffer treatment tJ1. The sea urchin...is taken out of the device.

Here, the electrode portion of the electrostatic chuck will be explained. In addition, in FIG. 1, the electrostatic chuck loa.

101) have the same configuration, so in the following description, the electrostatic chuck 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 chunk 10 for wafer suction has di-circular depressions 11a and 12a inside the JS surface, respectively.
A first and second electrode 11 made of a disc-shaped conductor such as metal.
12.

By the way, when automatically transporting a wafer, it is overwhelmingly often the case that the wafer is sucked up from the front side and transported. Therefore, the electrode section 17 is suspended on a wafer transfer device as an electrostatic chuck, and
It can be installed so that its suction side is facing downwards.

Here, the first of these. The second electrodes 11 and 12 are the insulating film 1
3.14, with a predetermined interval of 1]
are placed with a gap between them. 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 are recessed inside (lffi) leaving a portion of width W on the outer periphery of an approximately 1' circle with diameter R. , this portion of width W is the suction portion 15, 16 for the )]6 conductor wafer. Sucking? On each surface of part 15.18, +1
Insulating films 15a and l as part of the i+ insulating film 13.14.
ea is provided as a coated layer, and the thickness of these insulating films 15a and 16a is determined based on the suction force of the wafer and the like. The thickness of the insulating films 13 and 14 other than this portion is determined by taking into consideration that this electrode portion will have sufficient withstand voltage when it comes into contact with other metal portions.

Next, the asso-song reaction will be explained in detail with reference to FIGS. 4, 5(a), and 6.

As shown in FIG. 4, in the anosong process, the ozone supplied from the ozone + oxygen gas supply device 3 is heated inside the injection part 22a (or the same as the injection part 22) as follows. Eleven statements are lies.

03:02 +0 In this case, ozone is decomposed into acid J Iji
The life of t J' radical 0 depends on the temperature, and the 6th
As shown in the figure, it becomes extremely long at around 25°C.

However, 〆1! Is your degree high? Then, their lives suddenly become shorter.

- On the other hand, the ashing process using oxygen atom radicals is an oxidation chemical reaction, and the higher the temperature, the faster it occurs.

Moreover, a certain amount of time is required for the oxygen atom radicals to act on the wafer surface. So wafer 28
The simple question is how effectively to continue supplying oxygen atom radicals to the surface of the metal.

The associating process proposed in this invention efficiently supplies oxygen radicals to the surface of the wafer 28 and quickly removes reaction products from the wafer surface. ↑) In processing the synergistic effect of division by 1 and supply of oxygen atom radicals, the ashing speed can be increased to a processing speed suitable for single-wafer processing.

Therefore, it is important to create an appropriate gas flow space that supplies the oxygen atoms and divides the reaction products by υl.

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 temperature of 1111 degrees, the distance between the wafer mounting table 205 and the diffusion plate 200 will be 0.5 to 1111 degrees with respect to the wafer surface. It is necessary to do so. Further, the outermost position [1 position (position of slit 3121 in FIG. 4)] is determined so that the gas to be injected is blown outward by 5 mm or more from the outer diameter of the wafer 28.

By blowing the gas outward from the outer shape of the wafer 28 in this way, f'l11
A region is formed, and the 11 gas from the center and 71 (sides) is transported outward from the outer periphery of the wafer and is emitted from the wafer.

As a result, it is possible to facilitate the supply of sulan to the wafer surface and the contact of oxygen atom radicals, 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 become cone ff1 of the injection part 22a.
The rate held inside s203 becomes higher.

Then, as soon as ozone (03,02+O) and oxygen 02 are injected from the 13171 part of the diffusion plate 200, they are exposed to a high temperature atmosphere, but before their lifespan ends, they reach the wafer surface together with oxygen and the wafer surface A wave? Ashing (ashing) of the film that has been

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

As shown in FIG. 5(a), carbon monoxide, carbon oxide, and vaporized water (6) generated by ashing are as follows. The flow of oxygen (02) and non-Lancal ozone (0, y) emitted from the diffusion port < 200 is eastward, IJ1 is removed from the surface, and υ1 of ring play 1.222 is opened. 1. '+219 to t nobby (
It is carried to pipes 221 and 223, and is sequentially evacuated by 4 to the exhaust system.

Therefore, an environment can be created in which the surface of the wafer 28 is constantly exposed to the oxygen source r-Ranchal.

In FIG. 5(a), 28a is the surface portion of the wafer 28, and 281) is the surface portion of the wafer 28. 't
The arrow 32 indicates the portion of the resist that has been exposed to the diffuser plate 20.
It shows the flow of ozonator oxygen gas from zero.

Here, the wafer temperature is set at 300° C., and the distance (gap) between the surface of the wafer/mounting table 205 and the diffusion plate 200 (on the injection II side) is set as a parameter.
When we measured the ashing speed for the standard gas flow @ (normal temperature, normal condition 1) in the first section, as shown in Figure 7, the ashing speed for the 6# wafer was around 2sλ to 4sλ.
0sJ2 range (sj2: normal if; 11. normal pressure 1'l
In particular, it is a high-speed anno song processing.
), and gradually saturates from about 40 sλ/min.

In order to make this flow:, 1 correspond to the general wafer diameter, if we convert it to the flow per medium area of the wafer: I), it becomes 0°0
1~0. 25sJ! /min I Cm'.

Furthermore, when the relationship between the ashing speed of the diffuser plate and the wafer surface with respect to the gear knob is measured using the gas flow 111 as a parameter at a wafer surface temperature of 300° C., as shown in FIG. It exhibits a characteristic that converges toward a constant value regardless of the gas injection flow rate.

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) 211116. When the reaction time is 1 min, the characteristics are measured using the gas flow Bk as a parameter, as shown in Figure 9.
It can be understood that if the temperature is lowered to about 200°C, it will be difficult to remove.

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, 1 Iu of the outflow gas from the diffuser plate 200 is 1 degree to 15 degrees.
~50°C.

This agrees with the characteristics of the ozone decomposition 1' phase that we have seen in Figure 6.

Further, as shown in FIG. 16, when looking at the relationship between the ashing speed and the ozone elasticity by combining 1-4, the on/on concentration is 1., 11. There is a relationship in which the ashing speed increases by 1' as the ashing speed increases. But l OIT! , when t=+ is about 1% or more, it moves toward saturation. Note that this characteristic is for a 6″ wafer and its temperature is 250°C.
and the gas flow 11+L is 5 s Jl/min
, measurements were taken on the resist that had been stripped by plasma irradiation during etching step 1, assuming that the chamber internal pressure was about 700 Torr.

As can be understood from each characteristic graph, by forming a flowing gas space in a part of the wafer 1 and injecting or flowing ozone-containing gas onto the wafer,
This results in an hourly processing power of several μm/min. This realizes an anosong suitable for single-wafer processing and processing of 11-year wafers.

FIGS. 10(a) to 10(d) are explanatory diagrams of specific examples of a diffusion plate 200 that uniformly injects ozone+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 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. 1O(b), a hole 312 is provided in the center of a circle, and slits 313 are arranged radially with respect to the hole 312. In FIG. 10(C), holes 314 are provided in a radial manner, and the holes 314 become slightly hidden toward the outside. 1st
In FIG. 0(d), a sintered alloy 20021 is used as the diffusion plate 200, and porous holes 315 of 1:1 are uniformly formed on the sheet metal surface.

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

Here, in order to examine the effect of uniformly discharging gas from the diffusion plate 200, we examined two cases: a case in which holes are sparsely opened as shown in FIG. 10(f), and a case in which holes are opened sparsely as shown in FIG. In the former case, as shown in Figure 5(b), when comparing the case where the porous pores are uniformly distributed, as shown in Fig. 5(b),
The resist portion 28b is ashed in response to the gas flow 32 (arrow), and the ashing becomes uneven with gentle waves. On the other hand, in the case of the latter sintered alloy in which porous pores are uniformly distributed, a uniform ashing is formed as shown in FIG. 5(C).

Therefore, the gas injection 1-
1, which has the advantage that the processing time until complete ashing can be shortened and that the wafer is not easily damaged even if ozone is applied to the wafer surface.

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 the 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. -・Tsubauni/% The mounting table 205 and the wafer 28 are heated by the heating device 206 to a reaction temperature of 1.5 degrees. Therefore, the diffusion plate 200 is heated by the radiant heat emitted from the wafer mounting table 205 and the wafer X 28 side, and the surface of the diffusion plate 200 tends to rise by 44 degrees.

As a result, around injection +1, the gas i'1.1 degree or l h
", and the oxygen radicals supplied to the wafer surface [
11. will decrease. In particular, when the gap is large, the influence of heat is somewhat reduced, but the travel time of the oxygen radicals becomes longer, so there is no life left before reaching the surface of the wafer 28, including the influence of 2111 degrees Celsius. The number of oxygen source r radicals that are exhausted also increases. Moreover, if the gap is too small, it will be directly affected by the temperature on the wafer mounting table 205 side, and the 1A11 degrees 1-h' of the surface of the diffusion plate 200 will tend to become higher. Moreover, due to the gas flow +, 1 blown out from the diffusion plate 200, /! , the L h' values also differ by one degree.

For this reason, there are more optimal conditions for ashing processing. In reaction type (6) shown in FIG. 4, when the wafer temperature is about 200°C to 350°C, the more optimal gap is about 1 to 3 mm, and the gas flow I11 is at room temperature or room temperature. For a 6" wafer under the conditions of It becomes ze.

In addition, carbon dioxide reacted by oxygen atom radicals, -
・The reaction products such as carbon oxide and water are 1=, oxygen (02
) is carried away from the wafer surface by
There is Il:%.

In other words, if there is less ozone (O3), what will happen to the ashing rate (film j°)? If the ozone (O3) or oxygen (02) is low, the rate will be +
'6 Is it going to be sea urchin x human blood 1. Reaction/1 The product becomes stagnant and the reaction rate decreases.

Taking these four points into consideration, the optimal ozone
A suitable value of 1% is about 3Φ:11% to 54jt+t%.

Now, taking these matters into consideration, a specific example of a cooling structure for the injection section will be described below, which injects gas as low as possible at 7A+1 degrees while injecting gas uniformly.

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 made to run in a meandering manner while avoiding pickpocketing and to avoid pickpockets 318.

In addition, the injection ffl<22b shown in FIG. 11(b) is a case in which a cooling pipe 204b made of a serpentine pipe is placed on the outer surface of the diffuser plate 200 (on the Ueno 28 side) and communicated with the cooler 204. Similarly, the slit 318 is twisted in a manner that avoids the slit 318. In this case, in FIG. 11(a), (1)), the cooler 204 disposed around the cone portion 203 may not be provided.

By doing so, even if there is heat radiation from the wafer mounting table 205 side, the surface of the diffuser plate 200 can be suppressed to a low state, and the 111λ degree of the injected gas can be suppressed, allowing for more flexible conditions. Effective ashing process 1
12 or l'lJ Noh.

The injection part 22c seen in FIGS. 11(c) and 11(d) is a circle X1
It is not a cylindrical shape, but a cylindrical shape, and 1.4
A dome 22d for gas diffusion is arranged at 1° in the part,
After the gas is diffused in advance in this dome portion, it is sent to the diffusion plate 311 having a slit or the diffusion plate of the sintered alloy 200a.

In particular, in FIG. 11(c), a serpentine tube-shaped cooler 204c is built inside the cylindrical portion, and in FIG. 11(d), a ball 200b with a relatively large diameter is installed in order to make the injection uniform. There are 11 parts inside it. Note that these do not have a cooler on the outside, but similar to Figures 11(a) and (b),
Of course, the cooling pipe may be placed outside the cylindrical portion.

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

The injection section 33 shown in FIG. 12(a) consists of a diffusion tube 34 and a gas introduction tube 35 communicating at the center thereof. It is pivoted on the side.

Here, both ends of the diffusion tube 34 are closed, and on the side facing the wafer 28, there is an injection IZ'+36.38. ... or a plurality of them are arranged at predetermined intervals. Furthermore, spray 1 at opposite positions on the side surfaces of the ends (sides perpendicular to the wafer surface) with their backs turned to each other.
137.38 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 also plays the role of transporting the ashing product to the outside. Note that instead of the injection Ill 3 E3, a porous material may be used on 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 t,), and this shaft is pivotally supported on the floor side of the chamber 29, and the wafer mounting table 205 is rotated by a motor. This is an example of a configuration. In addition, the injection part 22a is the 12th
It may be tubular or rod-shaped as shown in Figure (a).

Comparing the effects of using and not using such rotation, we find that when using the rotation method, the processing time for the wafer is reduced by 1.7 strokes. Rotating method and same processing (1. Comparing this with the case of not rotating for a time, as shown in Figure 13, when not rotating, the resist is divided by filtration at the center of the wafer. In the surrounding area of Iruka,
A phenomenon is observed in which the remaining portions of Lenost 40 are not removed and remain as a striated pattern. Note that this was performed on a 6″ wafer.

It can be said that such force-rotation processing is self-effective in shortening the anno song processing time, and is also effective in ashing processing of the periphery of sea urchins, excluding the central part. In particular, it is effective for wafers with a diameter of 1-1, such as 6'' to 10''. In addition, Fig. 12(a)
In this case, since the gas injection part automatically rotates, there is an advantage that the device is in the middle line, or it is necessary to inject that much more 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, there is an advantage that less gas is ejected.

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

As shown in FIG. 14, to complete the ashing process, gas analyzers 1 and 17 are installed in front of the extraction device 4.

Then, carbon dioxide (C02
) The detection signal 5 corresponding to the concentration is determined as the end point/control device 8
The concentration of -carbon oxide is monitored manually, and when this concentration becomes zero or a predetermined value (++'f or more than 1.0), it is determined that the ashing process has ended -1'.

Here, the end point determination/control device 8 has a controller configured of a func- tion comparator and a microprocessor in 9, and receives an ashing process end point detection signal 417 from a comparator that receives the output of the gas analysis 1 fluid 7. After receiving the
Anno/Fugu device 2. The gas valve of the gas introduction pipe (see gas introduction pipe 202 in FIG. 2) and the tr lowering device 5 (motor 230 in FIG. 2) are controlled.

That is, when the end point is detected, a signal is generated to close the valve of the gas introduction pipe, thereby controlling to stop the gas injection. At the same time, an unloading signal from the wafer mounting table 21 is sent to the 't-+' unloading device 5, which is controlled, and the gear knob between the diffusion plate and the wafer mounting table is enlarged to remove the wafer. The mounting table (in the embodiment shown in FIG. 2, the injection unit) is moved to the standby position.

Upon receiving the standby position and setting (i:j-7) from the lifting device 5, the end point determination/control device 8 moves to the loader/unloader section on the wafer unloading side (the loader/unloader section 23 in FIG. 2).
1. Release the gate valve (gate valve 225 in FIG. 2) that communicates with the 1. Sugoi 1; Send the bow to the ashing device 2. Upon receiving this message, the ashing device 2 releases its gate valve 7 and opens the chamber (
Chamber 29 in FIG. 2 and wafer II
Communicate with the loader/unloader section on the +lt side.

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

Upon receiving this information, the ashing device 2
At the same time, the wafer handling mechanism is activated to pick up the wafer 28 on the wafer mounting table 21 (see wafer mounting table 205 in FIG. 2, HB6) -1- and carry it out from the chamber. Then, the wafer is received by a belt transport mechanism (see belt transport mechanism 24b in FIG. 2).

- When the wafer handling mechanism on the flange unloading side has completed unloading the wafer from the chamber, the ashing device 2 sends the end point determination/control device 8 to the end point determination/control unit 8.
Send out. At the time when this completion r tj'"J is received, the end point 'rll setting/set length control device controls the ashing device to close the gate valve (gate valve 225) communicating with the loader/unloader section on the wafer unloading side. 2
The valve is closed and the loader/unloader section on the wafer unloading side is not disconnected. Next, the loader/unloader section on the wafer loading side (loader/unloader r'l in Figure 2)
+< 23 a Valve (2nd
A control signal is sent to the unlocking device 2 to release the valve 224 in the figure.

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 operate the carry-in side wafer handling mechanism (transfer arm 25a in FIG. 2).
The ashing device 2 sends out the number.

The ashing device 2 operates the wafer handling mechanism on the carry-in side, picks up the wafer 28 from the belt conveyance mechanism (see belt conveyance mechanism 24a in FIG. 2), carries it into the chamber, and transfers the wafer 28 to the wafer mounting table 21. (wafer mounting table 205).

The wafer mounting table 21 holds the wafer in place.

When the wafer handling mechanism on the loading side completes loading the wafer, its art returns to the rotor/unloader.
At the time I, the ashing device 2 sends the completion r(+'?:J) to the end point r11 constant/control device 8.

The end point determination/control device 8 performs this i1. I received the bow! 1.
5-point wafer I &) ashing device 2
At the same time, -l-! of the wafer mounting table 21 is transferred to the unloading device 5. ii'Injection part 2 (in Figure 2, injection part 2
2 -'J) is sent.

The ashing device 2, which has received the control signal to close the valve, closes the valve and separates the chamber from the loader/unloader section on the LA side by 9 spaces. - On the other hand, the elevating device 5 that received the S'J of the wafer mounting table 21 controls the wafer mounting table 21 to close the gap between the diffusion plate and the wafer mounting table as necessary for the reaction. Set it to the basic gear knob (set it to the reaction position).

At the moment when the reaction position 1 depression L-1':J is received from the lifting device 5, the end point ζ11 constant/control device 8 opens the valve of the waste/9 person vibe (, i-; is generated, It controls the start of dregs injection.Then, I'JI 'A iJS is lil'11: '? and starts processing for ♀ winter publication.

Figure 15 shows the temperature in the 1-no-1 gas in this case.
, CI of carbon oxide! It is a graph showing I change.

As shown in the figure, as the ashing treatment time progresses, the carbon dioxide level gradually increases to 73 degrees and becomes constant, and the gear knob and sea urchin I\'s l in the oxidation reaction space! ll1 degree and gas Mf, iit: under conditions in the optimum range, 6#
For wafers, within 1 minute, and depending on gear 7 and wafer l+1λ degrees, and gas m iik.
~The anno song processing is completed in a few minutes, and the concentration rapidly approaches zero at this point.

Therefore, the end point of the assembly process plj can be determined by (d) comparing and detecting the carbon oxide concentration with a constant value of zero or near zero using a comparator.

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, for these, the end point of the ashing process may be determined by measuring 1,1 of the gas.

- On the other hand, as seen in this graph, the tendency for gas generation to start decreasing from a constant value and then reaching zero is almost the same characteristic for υ1 gas. therefore,
By detecting the change point A of this characteristic or the point B where the characteristic has decreased beyond the constant 4+', the end point r can be predicted.

The decreased point B can be detected by changing the reference value of the comparator, and the Y and survey route r points can be determined by adding a certain period of time to this detection point.

Furthermore, the detection of the change point A can be easily performed by combining a differential circuit or a peak detection circuit with a comparator.
can be realized.

By the way, when it is detected that the In of the υ gas is less than a predetermined value, the gas analysis 1117 and the determination section of the end determination/control device 8 shown in FIG. A detector (gas sensor) that detects 1t at a specific value or within a specific range, and an end point judgment circuit (judgment processing using a comparator, logic circuit, or microprocessor) that judges the end point r from the detected signal is sufficient. . On the other hand, υ
When detecting the change point of 1 gas, use a 1 gas measuring instrument, sensor, or only the change state that generates 1';''-J corresponding to 11 of the special electric gas. A sensor to detect it is essential.

As explained above in 1-1, in the embodiment, the diffusion plate is placed at the wafer's hem.
・In a suspended form, the diffuser plate side may blow gas from 1 to 1.
Furthermore, these may be arranged laterally with gear knobs at predetermined intervals.

In short, the arrangement relationship between these is not limited to seven dos, but it is sufficient that they face each other at a certain interval.

It goes without saying that a handling mechanism such as the one described above may be used to carry the wafer into and out of the azosing apparatus, and is not limited to the embodiment.

In the embodiment, in order to carry in the wafer, either the wafer mounting table or the diffusion plate is relatively moved to ensure a space for inserting the handling art.

However, these are the same as 11. You can also move up with ``-nikawa)''.

Furthermore, if a configuration is adopted in which the wafer 1 is sent to the wafer mounting table using a belt transfer mechanism and a pusher, etc., the distance between the diffusion plate and the wafer mounting table can be narrow, and an enlarged space into which the handling arm etc. enter is unnecessary. Since it will be a dog, the wet 1 year old's 1st place is the 1st place of the diffuser plate.

The hand movement mechanism is not essential.

In the embodiment, a case is described in which gas is injected, but it is also possible to simply cause ozone + oxygen gas to flow out into the reaction space. Therefore, it suffices to just leak into the instep.

In addition, in the embodiment, the structure of the injection part is circular 9
Are you holding up a circle with one shape and a tube shape?
For example, ozone and gas may be injected or flowed out using a disk-shaped object or a nozzle, and various shapes can be used.

So, this specification is 11" k i for one gun?
This includes a method in which a rod-shaped object is rotated to form a gas flow that is uniform in its locus and 14 plates.

The structure of the cooler is based on the case where the refrigerant flows through the pipes, but
This can be done by providing a space with a one-way structure in which the refrigerant flows directly into the injection part (cooling with water or cooling air, various liquids or gases, or even cooling metals using the Bertier effect, etc.). It's okay.

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

Furthermore, the higher the temperature of Ueno 1 during the ashing process, the faster the oxidation reaction rate;
This is also related to the loading/unloading speed of the wafer 1, and does not necessarily have to be set to a high value. Furthermore, the value is such that, even in terms of the life time of ozone, the reaction can be performed at a constant liJ culm or higher. Furthermore, if the ozone concentration of 11% can be set to a high value, it is possible to set the ozone concentration to a value even lower than usual. However, with the current equipment, the ozone generation iRtit% is considered to be at its limit at 10 to 13% culm degree 1);

In the embodiments, the explanation is centered on resist as a song target, but as mentioned in the prior art section, such ashing processing can be applied to various things such as removing ink and solvents. Any material may be used as long as it can be removed by oxidation.

In addition, the case where ozone is contained in oxygen gas is mentioned, but ozone is not limited to oxygen, but also gases that do not react with ozone, especially various inert gases such as N2 + A r + N e 5. It can be used by containing it.

[Effects of the Invention] As can be understood from the above explanation, in this invention, for example, an ozone outflow portion is provided at a position facing the sea urchin/1 at a predetermined interval, and This creates a space in which cooled gases of ozone and oxygen flow between the wafers, thereby continuously supplying new ozone to the wafer and oxidizing the oxygen atomic radicals and the film deposited on the wafer. While promoting the chemical reaction, non-radical oxygen (02) moves carbon dioxide, -carbon oxide, water, etc. generated after the reaction from the wafer surface in a vaporized state, υ
You can get 1 out.

As a result, the reaction surface of the film 9 deposited on the wafer L, for example, the oxidizing material film, can be fully exposed to the oxygen atomic radicals, which have a very strong oxidizing effect.

Therefore, it is possible to perform high-speed ashing processing, and an ashing apparatus suitable for single-wafer processing can be realized.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an ashing processing system according to an embodiment to which the ashing method of the present invention is applied, and FIG.
3(a) and (1) are cross-sectional explanatory views showing the overall configuration including the wafer transport mechanism in other similar embodiments. (a) is a sectional view taken along line II in (1)), (1)) is a 1' cross-sectional view, and Figure 4 is a
FIG. 5(a) is an enlarged explanatory diagram of the reaction part, and FIG.
Figures (b) and (C) are diagrams illustrating the relationship between the diffusion amount I-1 and the a/song state in the wafer, respectively.
The figure is a graph explaining the relationship between the decomposition half-life of ozone and the diffusion amount [-1 product temperature. Further, FIG. 7 is a graph explaining the relationship between the ashing rate and the gas flow [71] when the wafer surface temperature is 300'C, and FIG. l11 degrees 30
Figure 9 is a graph explaining the relationship between the ashing rate and the gap between the diffuser plate and the wafer surface at 0°C.
Figure 0 (a), (b), (e), (d) + (e), (
11(a), (1)), (c), and (d) are illustrations of specific examples of the gas cooling structure in the injection part, respectively. Explanatory diagram, 1st
Figure 2 (a) is an explanatory diagram of the person rotating the gas injection part,
FIG. 12(b) is an explanatory diagram of rotating the wafer side,
Figure 3 is an explanatory diagram of the Ara/Fugu effect in the Song Dynasty without simultaneous rotation.
FIG. 14 is a block diagram of an embodiment of the anno song process/steno process that determines the end of the arch process.
Figure 5 shows the l of carbon monoxide in the IJI-C gas.
A graph of agricultural rate change, Figure 1.6 is a graph explaining the relationship between anosong velocity and ozone concentration, and Figure 17 is a graph of
A by conventional ultraviolet rays. FIG. 2 is an explanatory diagram of a song device. 1... Ashing/Stem, 2.20... Ashing/Stem
3... oxygen gas supply device, 3 ct... gas flow] j1. Regulator, 3b...Ozone generator, 3c...Oxygen supply source, 4...υI air device, 5...M descending device, 6.../! ,,1 degree adjustment number, 7
...Gas analyzer, 8...End point side') J:,/control device, 10AL, 101)...Electrostatic charger, 21...
・Wafer mounting table, 21nr, 208... heating device, 22.22 a + 22 b... gas injection 71
S, 23 il+ 231)...Loader/unloader section, 24a, 24b...Belt transport mechanism section, 25a
, 25b... Transfer arm, 26a, 26b... Suction 71 chuck, 28... Ueno A131... Sliding. Mochi1. '1 Applicant East JJE Electron Co., Ltd. No. 3
Figure (G) 211 12
, No. 11a 12a Fig. 4 Fig. 5 (G)
28a No. 6121 Fig. 7 νI crawl ij 01℃ Wafer 棧 6 Ishi+T/
Flow rate (s2/1°) Fig. 8 Fig. 9: 01. ．． i ('C) Fig. 11 (C) (d) Fig. 12 (a) (b) Fig. 17 Fig. 13

Claims (5)

[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 gas is cooled and discharged. An ashing method characterized by (2) The flow space is formed by arranging an outflow part through which ozone-containing gas flows out, facing the wafer at a predetermined distance, and the temperature of the gas that is cooled and flows out is 50°C or less. Claim 1 characterized by
Ashing method described in section. (3) The ashing method according to claim 2, wherein the wafer is heated. (4) The ashing method according to claim 3, wherein the facing arrangement is such that the outflow portion is on top, and the wafer is heated at a temperature of 150 to 500°C. (5) The ashing method according to claim 3, wherein at least one of the wafer and the outflow portion moves up and down.