JP2524869B2 - Substrate surface treatment method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to the surface of a substrate when manufacturing a semiconductor such as an ultra large scale integrated circuit (VLSI) which requires miniaturization and high integration. In addition, the present invention relates to a substrate surface treatment method and apparatus for ashing a photoresist using active oxygen generated by activating at least one of ozone and oxygen.

<Prior Art> Conventionally, surface treatment of this kind of substrate is performed by
There was something like this:

A. First Conventional Example As disclosed in Japanese Patent Laid-Open No. 64-48421, a mixed gas of oxygen gas and water is made into plasma in a vacuum, and active species generated in the plasma are used as reactive species to manufacture semiconductors. The photoresist, which is considered as the largest organic contaminant in the process, is removed.

B. Second Conventional Example As disclosed in JP-A-1-189122, the photoresist is removed by the active oxidizing gas generated by the reaction gas containing ultraviolet light and ozone, the ultraviolet light energy, and the radiant heat from the radiant heat source. .

C. Third Conventional Example As disclosed in JP-A-1-233728, oxygen-ozone mixed gas containing water and ammonium nitrate is irradiated with ultraviolet rays to generate nitrous oxide (N ₂
O) gas and an oxygen / ozone mixed gas are caused to undergo an excited reaction, and the excited reaction is promoted by using water as a catalyst to obtain a high concentration of active oxygen so that the ashing rate can be improved.

D. Fourth Conventional Example As disclosed in Japanese Patent Application Laid-Open No. 57-210632, a modified layer of a photosensitive resin film is wet by immersing it in a substrate which is a strong oxidizing treatment liquid in which nitric acid is mixed with hydrogen peroxide. Oxidation is performed to weaken the resistance of the modified layer of the photosensitive resin film to oxygen plasma, and the modified layer of the photosensitive resin film is etched together with the photosensitive resin film by oxygen plasma.

<Problems to be Solved by the Invention> In the above-mentioned first and second conventional examples, there were the following secondary points.

Photoresist ashing speed is slow and processing capacity is limited.

It is difficult to remove metal impurities in the photoresist.

Resist after phosphorus (P) ion implantation (so-called P
It is difficult to remove the implant resist).

In addition, although the third conventional example can improve the ashing speed, it has the following drawbacks.

Depending on the temperature of the hot plate on which the substrate is placed, ammonium nitrate NH ₄ NO ₃ undergoes a chemical change, and there is a risk of explosion accompanying it.

The metal impurities in the photoresist are not removed.

Control of the peeling process requires a complicated end point detecting means of the peeling process.

Further, in the fourth conventional example, there is a drawback that the waste liquid treatment is required after the cleaning treatment and the treatment efficiency is low because of the wet oxidation treatment.

The present invention has been made in view of such circumstances, and an object of the present invention is to make it possible to improve the ashing speed while being safe, and to satisfactorily remove metal impurities in a photoresist. And

<Means for Solving the Problem> In order to achieve such an object, the invention of claim (1) supplies active oxygen generated by activating at least one of ozone and oxygen to the substrate surface. In the surface treatment method of the substrate for decomposing and removing the organic matter on the substrate surface, the acid-containing vapor generated by the evaporation of the aqueous solution containing acid to at least one of ozone and oxygen is mixed prior to activation. There is.

Further, the invention of claim (2) is a surface treatment method for a substrate, wherein active oxygen generated by activating at least one of ozone and oxygen is supplied to the substrate surface to decompose and remove organic substances on the substrate surface, Prior to activation, at least one of nitric oxide gas and nitrogen dioxide gas is mixed with at least one of ozone and oxygen.

Further, the invention of claim (3) is a method for surface treatment of a substrate according to the invention of claim (1) or (2), in which after the organic substances on the surface of the substrate are decomposed and removed, the substrate is pure. The feature is that water is supplied to clean the surface.

Further, the invention of claim (4) includes a gas supply means for supplying at least one of ozone and oxygen, and a gas activation means for activating at least one of ozone and oxygen supplied by the gas supply means. , A substrate surface treatment chamber that holds a substrate therein and supplies active oxygen activated by a gas activation means to the surface of the substrate to decompose and remove organic substances adhering to the substrate surface In the device, an aqueous solution containing an acid is stored therein, an acid-containing vapor generating means for evaporating the aqueous solution, and an acid-containing vapor for supplying the acid-containing vapor generated by the acid-containing vapor generating means to the gas activating means. Adjacent to the supply means and the substrate surface processing chamber, a pure water cleaning processing chamber provided with pure water supply means for supplying pure water to the substrate surface is provided.

As the aqueous solution containing an acid, hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, acetic acid, or a mixture thereof with a hydrogen peroxide solution can be used.

<Operation> The structure of the substrate surface treatment method according to the invention of claim (1) has the following operation.

The acid-containing vapor generated by the evaporation of the aqueous solution containing an acid as described above causes the following photochemical reaction upon being irradiated with ultraviolet light having wavelengths of 184.9 nm and 253.7 nm.

The chlorine radical Cl., Hydrogen radical H., or hydroxyl radical OH. Generated by this photochemical reaction is an organic substance (C _X H _Y O _Z ) such as a resist due to an oxygen radical or an ozone radical.
Acts as a catalyst to accelerate the decomposition of carbon dioxide gas (CO ₂ ) or water (H ₂ O), and the chlorine radical Cl · acts on metal impurities and converts it into a metal salt that is easily removed by heating or washing with water.

Oxygen radicals O ·, nitric oxide radicals NO · and nitrogen dioxide NO ₂ generated by this photochemical reaction have a strong oxidizing action and decompose and remove organic substances such as resist. Also,
Hydroxyl radical O ・, nitric oxide radical NO ・, and hydrogen radical H ・ are carbon dioxide (CO ₂ ) and water (H ₂ ) of organic substances (C _X H _Y O _Z ) such as resist due to oxygen radicals and ozone radicals.
₂ O) acts as a catalyst to accelerate the decomposition, and active acid groups such as hydroxyl radical OH and nitric oxide radical NO
It not only decomposes organic substances, but also acts on metal impurities and transforms it into a metal salt that is easily removed by sublimation by heating, sputtering during etching, or washing with water.

The nitric oxide radical NO · can decompose and remove potassium, magnesium, and phosphorus by its strong oxidizing action, and can accelerate the decomposition of the P implant resist. In addition, it is highly possible that the sidewall polymer after the Al electrode wiring dry etching can be removed at the same time.

Thus, the hydrogen radicals H · and hydroxyl radicals OH · obtained by activating the acid-containing vapor act as a catalyst for promoting the decomposition of organic substances by ozone radicals O ₃ ·, oxygen radicals O ·, or ultraviolet rays. In addition, the acid group radicals obtained by activating the acid-containing vapor (for example, NO in the case of nitric acid vapor and Cl in the case of hydrochloric acid vapor) not only promote the decomposition of organic substances but also It acts as a reactive species that reacts with metal impurities and produces metal salts.

Among the metal salts, metal chlorides have high volatility and are easily vaporized, and the metal salts remaining on the surface of the substrate are easily dissolved in water and can be removed by a washing step.

Further, according to the structure of the substrate surface treatment method of the invention of claim (2), there is the following action.

As nitric oxide and nitrogen dioxide are exposed to ultraviolet light, they generate nitric oxide radicals NO ・ and nitrogen dioxide radicals NO ₂・ through photochemical reactions, and these nitric oxide radicals NO ・ and nitrogen dioxide radicals NO ₂・The strong oxidative action promotes the decomposition of organic substances by oxygen radicals and ozone radicals, acts on metal impurities, and transforms it into a metal salt that is easily removed by sublimation by heating, sputtering during etching, or washing with water.

Then, the nitric oxide radical NO · and the nitrogen dioxide radical NO ₂ · decompose and remove potassium, magnesium and phosphorus due to their strong oxidizing action, and react with phosphorus (P) adhering to the resist after phosphorus (P) injection. The decomposition of the resist thus formed can be promoted. Moreover, it is highly possible that the sidewall polymer after dry etching of the A1 electrode wiring can be removed at the same time.

Further, according to the configuration of the substrate surface treatment method of the invention of claim (3), there are the following effects.

The metal impurity residue in the photoresist converted into the metal salt as described above is removed by washing with pure water.

That is, the solubility of nitrate is 91.8 g / 100 g (25%) for NaNO _3.
℃), 175.5g / 100g (100 ℃), KNO ₃ 31.59g / 100g (20
℃), 240g / 100g (100 ℃), CaNO ₃ 129.9g / 100g (20
℃), Fe (NO ₃ ) ₃ 87.3g / 100g (25 ℃), Ni (NO ₃ ) ₂ 94.2
It becomes g / 100g (25 ℃) and Cu (NO ₃ ) ₂ 60g / 100g (25 ℃).
Similarly, chloride, NaCl35.8g / 100g (20 ℃) , NiCl 2 67.8g
It is / 100g (26 ℃) and dissolves well in pure water.

Further, according to the configuration of the substrate surface treatment apparatus in the invention of claim (4), there is the following action.

In the substrate surface treatment chamber, removal of organic substances and conversion of metal impurities into metal salts are carried out, the substrate after the surface treatment is transferred to a pure water cleaning treatment chamber, and the converted metal salts are washed away with pure water.

<Example> Next, the example of the present invention is described in detail based on a drawing.

First Embodiment FIG. 1 is a schematic vertical sectional view showing a first embodiment of a substrate surface processing apparatus, in which a spin chuck 3 having a heater 2 for heating a substrate W is provided in a substrate surface processing chamber 1. In addition to the above, a quartz nozzle 5 is provided as a gas activating means, which has a built-in ultraviolet lamp 4 for irradiating ultraviolet rays having a wavelength of 184.9 nm and a wavelength of 253.7 nm. The ultraviolet lamp 4 may be suspended below the nozzle 5.

The spin chuck 3 is configured to be driven and rotated about a vertical axis by a motor M ₁ .

A large number of diffusion holes 5a are formed in the bottom plate of the nozzle 5 in a state in which they are uniformly distributed at a predetermined interval.

In order to improve the decomposition efficiency of organic substances and the conversion efficiency of inorganic substances, it is preferable to make the distance between the substrate W on the spin chuck 3 and the ultraviolet lamp 4 as short as possible.

A loading port 1a and a loading port 1b for the substrate W are formed in the peripheral wall portion of the substrate surface processing chamber 1 so as to face each other in the diametrical direction, and the loading port 1a and the loading port 1b are vertically moved by a driving mechanism (not shown). Can be opened and closed by sliding shutter 6
a and 6b are provided.

Outside the substrate surface processing chamber 1, a first substrate transfer mechanism 7a for loading the substrate W into the substrate surface processing chamber 1 through the loading port 1a, and unloading the substrate W from the substrate surface processing chamber 1 to the outside through the loading port 1b. In addition, a second substrate transfer mechanism 7b for loading into the pure water cleaning processing chamber 8 and a third substrate transfer mechanism 7c for loading out of the pure water cleaning processing chamber 8 are provided.

These first, second and third substrate transfer mechanisms 7a, 7b
And 7c each have the same structure, and as shown in the perspective view of FIG.
A first arm 11 attached to a rotary shaft of
Second arm 12 rotatably attached to the free end of 11
And a transmission mechanism 13 for transmitting the rotational movement of the first arm 11 to rotate the second arm 12, and a vacuum formed on the free end of the second arm 12 for sucking and holding the mounted substrate W by vacuum suction. It is composed of a chuck mouth 14 and the like.

An acid-containing steam generating means 15 for evaporating an aqueous solution containing an acid such as hydrochloric acid or nitric acid is connected to an introduction pipe 5b of the nozzle 5 via a steam supply pipe 17 provided with an opening / closing valve 16.

The acid-containing vapor generating means 15 is composed of a storage tank 18 for storing an aqueous solution containing an acid, and a temperature control means 19 such as a heater provided on an outer peripheral portion of the storage tank 18, and the acid stored in the storage tank 18. Is heated and evaporated by the temperature control means 19, and the acid-containing vapor generated by the evaporation is supplied to the nozzle 5 through the vapor supply pipe 17. Although not shown,
The steam supply pipe 17 is covered with a heat insulating material, and is configured so as not to liquefy at a temperature below the dew point when flowing inside.

An aqueous solution supply pipe 20 for replenishing an aqueous solution containing an acid and a carrier gas supply pipe 21 for supplying nitrogen N ₂ gas as a carrier gas are connected to the storage tank 18.
On-off valves 20a, 21a are provided in the respective 20,21.

The vapor supply pipe 17 having the opening / closing valve 16 and the carrier gas supply pipe 21 constitute an acid-containing vapor supply means.

Further, an oxygen cylinder 22 is provided at an intermediate position of the steam supply pipe 17,
A gas supply means consisting of a gas supply pipe 24 having an ozone generator 23 interposed therein is connected, and the ozone generator of the gas supply pipe 24 is connected.
On-off valves 24a and 24b are provided on both sides of 23, respectively.

An exhaust chamber 25 for gas such as CO ₂ and H ₂ O generated during decomposition and removal of organic substances is formed on the bottom plate of the substrate surface treatment chamber 1.
An exhaust pipe 26 communicating with it is connected to a vacuum pump (not shown) for suction and exhaust.

The substrate mounting table 27 is installed in the pure water cleaning processing chamber 8 so as to be movable up and down, and the top plate of the pure water cleaning processing chamber 8 is
For example, a pure water supply nozzle 28 is provided as a pure water supply means for supplying high temperature pure water of 80 ° C.

The substrate mounting table 27 is configured to be driven and rotated by a motor M ₂ around a vertical axis. Further, on the substrate mounting table 27, pins 27a are erected at diametrically opposed positions, and projections 27b for holding the substrate are attached inside them.

A loading port 8a and a loading port 8b for the substrate W are formed in the circumferential wall portion of the deionized water cleaning processing chamber 8 so as to face each other in the diametrical direction, and the loading port 8a and the loading port 8b are vertically moved by a drive mechanism (not shown). Shutters 29a and 29b are provided so that they can be opened and closed by sliding.

A drain and a pipe 30 for exhaust are connected to the bottom plate of the pure water cleaning processing chamber 8.

By using the substrate surface treatment apparatus having the above configuration, the substrate surface treatment method according to claim (1) is implemented.

That is, the acid-containing vapor generated by the acid-containing vapor generating means 15 by evaporation of the aqueous solution containing an acid and the ozone generated by the ozone generator 23 are supplied to the nozzle 5, and the ultraviolet lamp is used for the acid-containing vapor and ozone. 4 is irradiated with the ultraviolet ray, and the acid-containing vapor and ozone activated by the ultraviolet ray are passed through the diffusion holes 5a ...
Is uniformly supplied to the surface of the substrate W held by the substrate W to decompose and remove organic substances on the substrate surface and convert metal impurities into metal salts.

After the processing, the second transfer mechanism 7b transfers the substrate W onto the substrate mounting table 27 in the pure water cleaning processing chamber 8,
Pure water is supplied from the pure water supply nozzle 28 to the substrate W placed on the substrate placing table 27 to wash and remove the aforementioned metal salt.

As pure water supplied from the pure water supply nozzle 28, it is possible to accelerate the removal of metal salts by using high temperature pure water, but for example, an ultrasonic vibrator is attached to the nozzle and a frequency of 800 kHz or higher is set. The ultrasonic waves may be added to pure water to enhance cleaning efficiency, or pure water at room temperature may be supplied.

Second Embodiment FIG. 3 is a schematic vertical sectional view showing a second embodiment of the substrate surface treatment apparatus. The difference from the first embodiment is as follows.

That is, in place of the ultraviolet lamp 4 as the gas activating means of the first embodiment, a plasma generating means 32 having a microwave generating means 31 is provided, and the plasma generating means is provided.
With respect to 32, the storage tank 18 is connected via a steam supply pipe 33 having an opening / closing valve 33a, and an oxygen cylinder 22 is connected via an oxygen supply pipe 34 having an opening / closing valve 34a, and
The plasma generating means 32 and the nozzle 5 are connected via a pipe 35 having an opening / closing valve 35a.

The other structure is the same as that of the first embodiment, the same reference numerals are given, and the description thereof is omitted.

According to the configuration of the second embodiment, both the acid-containing vapor and the oxygen gas are activated in the plasma generating means 32 and then supplied to the nozzle 5.

Third Embodiment FIG. 4 is a schematic vertical cross-sectional view showing a third embodiment of the substrate surface treatment apparatus used for carrying out the substrate surface treatment method of claim (2). The difference from the embodiment is as follows.

That is, a nitrogen dioxide cylinder 36 is provided in place of the acid-containing vapor generating means 15 of the first embodiment, and the nitrogen dioxide cylinder 36 and the nozzle 5 are connected via a nitrogen gas supply pipe 37 having an opening / closing valve 37a. It is connected.

Since the other configurations are the same as those of the first embodiment, the deionized water treatment chamber 8 is not shown, and the same parts are denoted by the same reference numerals and the description thereof is omitted.

According to the configuration of the third embodiment, both the nitrogen dioxide gas and ozone are supplied to the nozzle 5 and activated by the ultraviolet lamp 4, and the activated ozone radicals and nitrogen dioxide radicals of the substrate W are generated. Supplied on the surface.

In the third embodiment, nitric oxide may be supplied instead of nitrogen dioxide. Also in the third embodiment,
Similar to the second embodiment shown in FIG. 3, instead of the ultraviolet lamp 4, the gas may be activated by plasma generating means provided with microwave generating means.

 Next, the experimental results will be described.

In the experiment, the substrate surface treatment is performed using the same structure as the substrate surface treatment chamber 1 in the first embodiment described above, and after the surface treatment of the substrate W is performed in the same substrate surface treatment chamber 1. A pure water supply nozzle was introduced and a cleaning treatment with pure water was performed.

Also, as the sample substrate, a 5-inch N (100) type silicon wafer is used, and the silicon wafer is kept at a temperature of 230
After dehydration bake at ℃ for 1 minute, while rotating at 5000rpm, after applying a positive photoresist [OFPR-800 (trade name) manufactured by Tokyo Ohka Co., Ltd.] to a film thickness of 1-2μm The product prebaked at a temperature of 135 ° C. for 1 minute was used.

 Then, the film thickness on the surface was measured at 108 points.

First, ultraviolet rays are radiated to ozone and hydrochloric acid vapor obtained by evaporating hydrochloric acid having an azeotropic composition concentration of about 20%, and the resultant is supplied to a substrate for processing, which is referred to as a first embodiment product A1.

Next, the nitric acid vapor having azeotropic composition concentration of 69% and ozone are irradiated with ultraviolet rays and supplied to the substrate to be treated, which is referred to as a second embodiment product A2.

In addition, the stripping solution [RA-stripper (trade name) manufactured by Kanto Kagaku Co., Ltd.] in which nitrogen dioxide is added to nitric acid with a concentration of 98% is irradiated with ultraviolet rays on the vapor and ozone to be supplied to the substrate. This is processed to obtain a third embodiment product A3.

On the other hand, ozone is irradiated with ultraviolet rays and supplied to a substrate for processing, which is referred to as a first comparative product B1.

Further, ozone obtained by adding nitrogen gas is irradiated with ultraviolet rays and supplied to the substrate to be processed, which is referred to as a first comparative product B2.

In the example product, the ozone supply rate was 10 for 1 minute and the carrier gas supply rate was 2 for 1 minute, while the ozone supply rate in the first comparative example product B1 was 12 for 1 minute, and 2 In the comparative example product B2, the supply amount of ozone was 10 for 1 minute and the supply amount of nitrogen gas was 2 for 1 minute. In each case, the temperature of the hot plate in the spin chuck 3 during the processing was 250. ℃
And the ashing time was 3 minutes.

After the above processing, the first to third embodiment products A1, A2, A3,
Set the film thickness of the substrate of each of the first and second comparative example products B1 and B2 to 1
08 points were measured.

The ashing speed (nm / 3min) of each of the first and second example products A1 and A2 and the first and second comparative example products B1 and B2 when the hot plate temperature was set to 250 ° C. As a result, the results shown in the graph of FIG. 5 were obtained.

Also, the second and third embodiment products A when the hot plate temperature is set to 250 ° C. and 300 ° C.
When the ashing speeds (nm / 3 min) of 2, A3 and the second comparative product B2 were obtained, the results shown in the graph of FIG. 6 were obtained.

Next, the experimental results obtained by the SiMS analysis will be described.

In this experiment, ²⁸ Si ⁺ , ²³ Na ⁺ , ²⁷ Al ⁺ , ³⁹ K ⁺ , ⁴⁰ Ca ⁺ , ⁵⁶ F were analyzed by SiMS analysis at predetermined 3 points on each substrate.
Measure the ionic strength of each of e ⁺ and ⁵² Cr ⁺ and calculate the average value, then ²³ Na ⁺ , ²⁷ Al ⁺ , ³⁹ K ⁺ , ⁴⁰ Ca ⁺ , ⁵⁶ Fe ⁺ , ⁵² Cr
^The ratio of each ionic strength to that of ²⁸ Si ⁺ was determined.

 The results are shown in the table below.

Columns I to VI in the above table show the results of the following treatments.

Column I: The substrate without photoresist was simply exposed to ozone radicals for 45 minutes.

Column II: The photoresist was ashed with ozone radicals for 45 minutes.

Column III: Ozone was mixed with chlorine vapor using nitrogen gas as a carrier gas, activated, and the photoresist was ashed for 45 minutes.

Column IV: Nitric acid vapor [RA stripper described above (the same applies below)] was mixed with ozone using nitrogen gas as a carrier gas, and these were activated to subject the photoresist to 50% overashing.

Column V: Nitric acid vapor is mixed with ozone by using nitrogen gas as a carrier gas, and these are activated to subject the photoresist to 50% over-ashing, and then pure water is applied to the horizontally rotating substrate for 60 seconds (flow rate 1.5 / min) and then shaken off by high speed rotation to dry.

Column VI: After subjecting the photoresist to 50% overashing with ozone radicals, pure water was supplied to the horizontally rotating substrate for 60 seconds (flow rate 1.5 / min), and then it was shaken off and dried by high-speed rotation.

 Next, the above experimental results will be considered.

First, consider the ashing speed. From the results shown in FIG. 5, addition of hydrochloric acid vapor or nitric acid vapor has an effect of increasing the ashing rate, and the effect is remarkable when nitric acid vapor is added. This is presumed to be due to the effect of the nitric oxide radicals and nitrogen dioxide radicals, which are involved in the reaction as a reaction species, rather than the chlorine radicals, which are involved in the reaction as a catalyst, but it should be sufficiently activated by ultraviolet light energy. Therefore, it is considered that the effect can be enhanced even in the case of hydrochloric acid vapor. The results in FIG. 6 show that the higher the concentration of nitric acid in the vapor source (vapor source), the higher the ashing rate. Since nitric oxide radicals and nitrogen dioxide radicals participate in the decomposition of the photoresist as reactive species, the higher the concentration, the higher the reaction rate. It is considered that such an addition effect of nitric acid vapor is also recognized in the (microwave) plasma asher. When an azeotropic composition is used as the acid aqueous solution, the concentration of the acid-containing vapor generated by the evaporation can be kept constant, so the decomposition process of the photoresistor is controlled by a simple method such as time control. It becomes possible.

 Next, the cleaning effect will be considered.

Comparing columns I and II shows that a considerable amount of sodium ²³ Na ⁺ remains on the silicon wafer surface after photoresist ashing.

²⁷ Al ⁺ does not appear to be present in the photoresist.
⁴⁰ Ca ^{+ is} also not present in the photoresist. ⁵⁶ Fe ⁺ is ⁵⁶ Si ₂ ⁺
And the peaks overlap, it is difficult to judge. ^It seems that ³⁹ K ⁺ and ⁵² Cr ⁺ are slightly included.

Therefore, the elements will be limited to ²³ Na ⁺ , ³⁹ K ⁺ , and ⁵² Cr ⁺ to evaluate various cleanings. Comparing columns II and III, the strength ratio of ²³ Na ⁺ , ³⁹ K ⁺ , and ⁵² Cr ⁺ is slightly reduced by the addition of hydrochloric acid vapor, but compared to column I, ²³ Na ^{+ on the} surface of the silicon wear. , ³⁹ K ⁺ remains in a considerable amount. The cleaning effect as expected was not recognized. It can be seen that chlorides such as NaCl and KCl generated by hydrochloric acid vapor cannot be removed even under the condition of ultraviolet irradiation of 250 ° C to 300 ° C and are still transferred and adsorbed on the wafer surface. V
When the column and the column VI are compared, ²³ Na ⁺ is slightly less ashed by adding nitric acid vapor, and ³⁹ K ⁺ and ⁵² Cr ⁺ have opposite results. Even if the nitric acid vapor is not added, the effect of cleaning with pure water is great, and the cleanliness is increased to the reference level in column I. It was found that the cleaning effect with pure water was extremely large.

Thus, it is clear from the results of FIGS. 5 and 6 that the ashing rate of the positive photoresist can be improved by adding hydrochloric acid vapor or nitric acid vapor. It was clear from the columns and columns VI that the cleaning effect can be made extremely high by cleaning with pure water.

Further, from the decomposition performance when nitric acid vapor is added, it is also possible to have a removing effect on the resist after the phosphorus (P) ion implantation treatment and a side wall polymer removing effect after the reactive ion etching of the aluminum (Al) wiring cutting board. I can guess.

The gas activating means described above is not limited to the ultraviolet lamp 4 as in the first embodiment and the plasma generating means provided with the microwave generating means as in the second embodiment, but is activated by heating. But good.

In the above embodiment, ozone or oxygen gas is activated and supplied to the substrate, but both ozone and oxygen gas may be supplied to the substrate.

In the first or second embodiment, the ozone and the acid-containing vapor or nitrogen dioxide are irradiated with ultraviolet rays to be activated and then supplied to the surface of the substrate W.
It is also possible to supply ozone and acid-containing vapor or nitrogen dioxide to the surface of the substrate and irradiate it with ultraviolet rays. In short, it is sufficient that the surface of the substrate W can be treated with ozone and acid-containing vapor or nitrogen dioxide activated by UV irradiation.

In the substrate surface treatment apparatus of the above-mentioned embodiment, the surface treatment with ozone and acid-containing vapor or nitrogen dioxide and the cleaning treatment with pure water are performed in separate chambers, respectively. May be performed in the same chamber as described in the experiment.

In each of the above-described embodiments, a single-wafer type surface treatment apparatus is shown, but as the present invention, a substrate board is used to collectively surface-treat a large number of substrates, that is, a so-called batch type surface treatment apparatus. Can also be applied.

In addition to the above-mentioned examples, it is also possible to use an aqueous solution containing other acids such as hydrofluoric acid (HF + H ₂ O) and sulfuric acid (H ₂ SO ₄ + H ₂ O).

<Effects of the Invention> According to the substrate surface treatment method of the invention of claim (1), the active acid group promotes the decomposition of organic substances by oxygen radicals and ozone radicals, so that the ashing rate can be improved. became.

Moreover, since the active acid groups act on the metal impurities in the resist to convert them into metal salts, the metal impurities can be safely removed without the risk of explosion as in the case of conventional ammonium nitrate. It was

Furthermore, since promotion of decomposition and removal of organic substances and conversion of metal impurities into metal salts are carried out by acid-containing vapor generated by evaporation of an acid-containing aqueous solution, it is considered that impurities are mixed in the acid-containing aqueous solution. However, it has become possible to perform excellent decomposition and removal of organic substances and conversion of metal impurities into metal salts without supplying the impurities to the substrate surface.

Further, according to the substrate surface treatment method of the invention of claim (2), the decomposition of organic substances by oxygen radicals and ozone radicals is promoted by the strong oxidizing action of nitric oxide radicals and nitrogen dioxide radicals. You can now improve the ashing speed.

Moreover, since nitric oxide radicals and nitrogen dioxide radicals act on metal impurities in the resist to convert them into metal salts, there is no risk of explosion as in the case of conventional ammonium nitrate, and metal impurities can be safely removed. It can be removed.

In addition, since phosphorus can be decomposed by nitric oxide radicals and nitrogen dioxide radicals, the decomposition of the resist after the phosphorus (P) ion implantation process, which is the most difficult to peel off, can be promoted.
The possibility of removing the sidewall polymer after dry etching of the substrate surface on which the Al electrodes are wired is great, and the versatility can be improved, which is useful.

Further, according to the substrate surface treatment method of the invention of claim (3), since the metal salt is washed and removed with pure water, the metal salt can be surely avoided from remaining, and the metal impurities can be removed without using a chemical solution. Can be satisfactorily removed, the cleaning process can be simplified, and the processing efficiency can be improved.

Further, according to the substrate surface treatment apparatus of the invention of claim (4), the removal of organic substances, the conversion of metal impurities into metal salts, and the cleaning with pure water are performed in different processing chambers. It is possible to prevent water droplets from adhering to the peripheral wall in the processing chamber as water droplets due to scattering, and to mix water droplets of pure water into the acid-containing vapor during the next supply of the acid-containing vapor, and the particles and impurities in the atmosphere onto the substrate. It became possible to reliably prevent the adhesion.

[Brief description of drawings]

The drawings show an embodiment of a substrate surface treatment method and apparatus according to the present invention. FIG. 1 is a schematic vertical sectional view showing a first embodiment of a substrate surface treatment apparatus, and FIG. FIG. 3 is a perspective view, FIG. 3 is a schematic vertical sectional view showing a second embodiment of the substrate surface treatment apparatus, and FIG. 4 is a schematic sectional view showing a third embodiment of the substrate surface treatment apparatus, FIG. FIG. 6 is a graph showing experimental results of ashing speed. 1 ... Substrate surface treatment chamber 4 ... UV lamp as ultraviolet irradiation means 8 ... Pure water cleaning treatment chamber 15 ... Acid-containing vapor generation means 28 ... Pure water supply nozzle as pure water supply means 31 ... Micro Wave generation means 32 …… Plasma generation means W …… Substrate

Claims (4)

(57) [Claims] 1. A method for treating a surface of a substrate, wherein active oxygen produced by activating at least one of ozone and oxygen is supplied to the surface of the substrate to decompose and remove organic substances on the surface of the substrate. A method for surface treatment of a substrate, comprising mixing an acid-containing vapor generated by evaporation of an aqueous solution containing an acid with at least one of oxygen. 2. A method for treating a surface of a substrate, wherein active oxygen produced by activating at least one of ozone and oxygen is supplied to the surface of the substrate to decompose and remove organic substances on the surface of the substrate. At least one of the oxygen,
A method for treating a surface of a substrate, which comprises mixing at least one of nitric oxide gas and nitrogen dioxide gas. 3. The substrate surface treatment method according to claim 1, wherein after decomposing and removing organic substances on the substrate surface, pure water is supplied to the substrate to clean the surface. Method for surface treatment of substrate. 4. A gas supply means for supplying at least one of ozone and oxygen, a gas activation means for activating at least one of ozone and oxygen supplied by the gas supply means, and a substrate held therein. In a substrate surface treatment apparatus equipped with a substrate surface treatment chamber for supplying active oxygen activated by gas activation means to the surface of the substrate to decompose and remove organic substances adhering to the substrate surface, an aqueous solution containing an acid Acid-containing vapor generating means for storing the inside thereof and evaporating the aqueous solution, acid-containing vapor supply means for supplying the acid-activating vapor generated by the acid-containing vapor generating means to the gas activating means, and the substrate surface treatment A surface treatment apparatus for a substrate, characterized in that a pure water cleaning treatment chamber provided with a pure water supply means for supplying pure water to the surface of the substrate is provided adjacent to the chamber.