JP2007243045A - Semiconductor device manufacturing method and electronic device manufacturing method - Google Patents

Abstract

A resist film which is used as a mask in impurity ion implantation and has a deteriorated layer is efficiently removed.
A gas using a mixed gas of hydrogen and oxygen as a fuel when impurity ions are implanted using a resist film 107 formed on a glass substrate 100 as a mask to remove the resist film 107 on which an altered layer 107a is formed. The resist film 107 is removed by performing a process using a burner flame as a heat source. At this time, the first ashing in which a halogen compound gas is further added, and then the mixed gas ratio of hydrogen and oxygen is larger than the stoichiometric composition ratio of water (H ₂ O), which is 2 mol: 1 mol. The second ashing is performed in an oxygen-rich situation.
[Selection] Figure 12

Description

  The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for removing a resist film in a manufacturing process of a semiconductor device.

  A semiconductor device has a laminated structure of a semiconductor film, an insulating film, a conductive film, and the like, and desired elements, wirings, and the like are formed by repeating patterning of these films. As will be described in detail later, the patterning is typically performed by a process of forming a resist film having a desired shape by a photolithography technique and an etching process using the resist film as a mask. The resist film is also used when impurity ions are implanted into a semiconductor substrate or semiconductor film.

  Thus, the formation of the resist film is indispensable in the manufacturing process of the semiconductor device.

  For example, in the following Patent Document 1 (Japanese Patent Laid-Open No. 7-273186), the silicon oxide film (12) is patterned in order to reduce the contamination of the silicon substrate by removing the mask after ion implantation at a high dose. A technique for forming a mask (13) and performing ion implantation using the mask (13) is disclosed.

Further, in Patent Document 2 (Japanese Patent Laid-Open No. 2004-157424), a resist having a hardened surface layer is easily removed in a short time without damaging other layers or generating dust. Therefore, the surface of the resist (3) is irradiated with an ultrashort pulse laser beam (20), and at least a part of the surface hardened layer (9) is removed by ablation, or cracks ( 21), and a technique for removing the exposed resist (9) by ashing or the like is disclosed. The numbers in parentheses are the code numbers of the publication.
JP-A-7-273186 JP 2004-157424 A

  The present inventor is engaged in research and development of semiconductor devices and is examining a method for removing a resist film.

  In particular, as will be described in detail later, ions are implanted into the surface of the resist film used as a mask at the time of impurity ion implantation and deteriorated. As a result, it is difficult to remove with a normal resist removing solution or ashing, and the altered layer becomes dust and contaminates the semiconductor device. Furthermore, there is a problem that the dust acts as a mask and obstructs the removal of the resist film that has not deteriorated.

  On the other hand, the inventor has been conducting research and development related to an apparatus and process using a hydrogen flame, which will be described in detail later, and has been intensively studying the application and application of the process to a semiconductor device. The hydrogen flame treatment refers to treatment using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source.

  Therefore, an object of the present invention is to remove a resist film by a treatment using a hydrogen flame. In particular, it is an object to efficiently remove a resist film that is used as a mask during impurity ion implantation and has a deteriorated layer. It is another object of the present invention to improve the characteristics of a semiconductor device by removing a resist film with high accuracy.

  (1) A method of manufacturing a semiconductor device according to the present invention is a method of manufacturing a semiconductor device including a step of removing a resist film formed on a substrate, and a mixed gas of hydrogen and oxygen is used as a fuel for the resist film. The resist film is removed by performing a treatment using a gas burner flame as a heat source.

  Thus, since the process using the flame of the gas burner as the heat source was performed, the resist film can be efficiently removed. In particular, by using a gas burner, the gas type and gas flow ratio can be easily changed, and the resist film can be removed with good controllability. Further, since hydrogen is used as the combustion gas, contamination of the semiconductor device can be reduced.

  For example, the resist film is used as a mask during impurity ion implantation, and has a deteriorated layer on the surface thereof.

  For example, the treatment is performed by further adding a halogen compound gas to the mixed gas.

  For example, the halogen compound gas is a fluorocarbon gas.

  For example, the processing is performed by scanning the flame of the gas burner relative to the substrate.

  For example, the resist film is removed while maintaining the substrate temperature at 100 ° C. or lower.

  For example, the processing is performed while adjusting the substrate temperature by adjusting the scanning speed of the gas burner or the distance between the substrate and the flame.

  The treatment is performed using, for example, the gas burner in which the exhaust port is formed in the vicinity of the flame, and is performed while sucking debris of the altered layer of the resist film from the exhaust port.

  (2) A method for manufacturing a semiconductor device according to the present invention is a method for manufacturing a semiconductor device, wherein (a) a step of implanting impurity ions using a resist film formed on a substrate as a mask, and (b) the resist film (B1) a first step of removing the altered layer formed on the surface of the resist film, and (b2) a second step of removing the resist film inside the altered layer. Removing the resist film, and the step (b1) is a step of performing a first treatment using a flame of a gas burner in which a halogen compound gas is added to a mixed gas of hydrogen and oxygen serving as a fuel as a heat source. The step (b2) is a step of performing a second process using a flame of a gas burner in which the amount of the halogen compound gas added is smaller than that of the first process as a heat source.

For example, the step (b2) is a process using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source, and the ratio of the mixed gas of hydrogen and oxygen is the stoichiometric amount of water (H ₂ O). This is a treatment performed in a state where the composition ratio of oxygen is larger than the theoretical composition ratio of 2 mol: 1 mol.

For example, the step (b2) is a process using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source, and the ratio of the mixed gas of hydrogen and oxygen is the stoichiometric amount of water (H ₂ O). The process is performed in a state where the oxygen radical (O ^* ) is richer than when the stoichiometric composition ratio is 2 mol: 1 mol, and thereafter, the hydrogen / oxygen mixed gas ratio is changed to the stoichiometry of water (H ₂ O). And a treatment performed in a state where the hydroxyl radical (OH ^* ) is richer than when the composition ratio is 2 mol: 1 mol.

  (3) A method for manufacturing an electronic device according to the present invention is a method for manufacturing an electronic device having a semiconductor device, and includes the method for manufacturing the semiconductor device. Here, electronic devices include various devices such as a mobile phone, a video camera, a television, a roll-up television, a large screen, a personal computer, and a portable information device (so-called PDA).

  In this embodiment mode, a resist film, in particular, a resist film used as a mask at the time of impurity ion implantation is removed using a gas burner using a mixed gas of hydrogen and oxygen as a fuel.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same or related code | symbol is attached | subjected to what has the same function, and the repeated description is abbreviate | omitted.

1) Semiconductor Manufacturing Apparatus First, a semiconductor manufacturing apparatus used for manufacturing a semiconductor device according to the present embodiment will be described with reference to FIGS.

  FIG. 1 is a diagram showing a configuration example of a semiconductor manufacturing apparatus used for manufacturing the semiconductor device of the present embodiment. In FIG. 1, pure water is stored in a water tank 11, and water is supplied to an electrolysis tank (electrolysis device) 12. Water is electrolyzed by the electrolysis tank 12 and separated into hydrogen gas and oxygen gas. The separated hydrogen gas and oxygen gas are supplied to the gas controller 15. The gas controller 15 includes a computer system, a pressure regulating valve, a flow rate adjusting valve, various sensors, and the like. The supply amount of hydrogen gas and oxygen gas (mixed gas) supplied to the downstream gas burner 22 according to a preset program, Adjust supply pressure, mixing ratio of both gases, etc.

Further, the gas controller 15 further introduces hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) supplied from a gas storage tank (not shown) into the aforementioned mixed gas and supplies it to the gas burner 22. Thereby, the mixing ratio (mixing ratio) of hydrogen and oxygen in the mixed gas is shifted from the stoichiometric composition ratio (H ₂ : O ₂ = 2 mol: 1 mol) of water (H ₂ O), and hydrogen excess (hydrogen rich) or An oxygen-rich (oxygen-rich) mixed gas is obtained.

The gas controller 15 can further introduce an inert gas such as argon (Ar), helium (He), nitrogen (N ₂ ), etc., supplied from a gas storage tank (not shown) into the mixed gas. Thereby, the flame temperature (combustion temperature) and flame state of the gas burner 22 are controlled.

  The water tank 11, the electrolysis tank 12, and the gas controller 15 described above constitute a fuel (raw material) supply unit.

  A chamber (processing chamber) 21 that forms a closed space is disposed downstream of the gas controller 15. In the chamber 21, a gas burner 22 for generating a heat treatment flame, a stage substrate 51 on which a processing target substrate (semiconductor substrate, glass substrate, etc.) 100 is placed and movable relative to the gas burner 22, etc. Is arranged.

  The atmosphere in the chamber 21 is not limited to this. For example, the internal pressure can be set to atmospheric pressure to about 0.5 MPa, and the internal temperature can be set to room temperature to about 100 ° C. In order to keep the atmospheric pressure in the chamber 21 in a desired state, the aforementioned inert gas such as argon can be introduced into the chamber 21.

  The stage unit 51 is provided with a mechanism for moving a table on which a substrate is placed at a constant speed to prevent particles. In addition, in order to prevent a heat shock of the substrate 100 due to a sudden temperature difference or the like, a mechanism for heating (preheating) or cooling is provided on the mounting table of the substrate 100, and this temperature control is performed by an external temperature adjustment unit 52. Made. An electric heater mechanism is used for heating, and a cooling mechanism using cooling gas or cooling water is used for cooling.

  FIG. 2 is a plan view illustrating a configuration example of a gas burner unit of the semiconductor manufacturing apparatus. As shown in FIG. 2, the gas burner 22 of the semiconductor manufacturing apparatus of FIG. 1 is formed by a longitudinal member that is larger than the width of the stage portion 51 (the vertical direction in the drawing), and emits a flame having a width wider than the width of the stage portion 51. it can. The gas burner 22 is configured to scan the substrate 100 by moving the stage unit 51 in a direction orthogonal to the longitudinal direction of the gas burner 22 (arrow direction in the figure) or by moving the gas burner 22. ing.

  FIG. 3 is a cross-sectional view illustrating a configuration example of a gas burner unit of a semiconductor manufacturing apparatus. As shown in FIG. 3, the gas burner 22 includes a gas guide tube 22a provided with a gas outlet hole for leading the mixed gas to the combustion chamber, a shield 22b surrounding the guide tube 22a, and a gas mixture surrounded by the shield 22b. The combustion chamber 22c is combusted, the nozzle 22d is an outlet through which the combustion gas exits from the shield 22b, the mixed gas outlet 22e provided in the air guide tube 22a, and the like.

If the gap (distance) between the nozzle 22d and the substrate 100 is set wide, the pressure decreases when the combustion gas is discharged from the nozzle. If the gap between the nozzle 22d and the substrate 100 is set so as to close (squeeze), the pressure drop of the combustion gas is suppressed and the pressure increases. Therefore, the gas pressure can be adjusted by adjusting the gap. Water vapor annealing, hydrogen rich annealing, oxygen rich annealing, etc. can be promoted by pressurization. Various types of annealing can be selected by setting the mixed gas. In the figure, the state of ejection of water vapor (H ₂ O vapor) is shown.

  As will be described later, by forming a plurality of gas outlets 22e or a linear shape, the flame (torch) shape of the combustion chamber 22c of the gas burner 22 is linear (long flame), a plurality of torch shapes, etc. Can be. The temperature profile in the vicinity of the gas burner 22 is preferably set to be rectangular in the flame scanning direction by the design of the outlet 22e and the nozzle 22d of the shield 22b.

  FIG. 4 is a diagram illustrating a first configuration example of the gas burner unit of the semiconductor manufacturing apparatus. 4A is a sectional view of the gas burner 22 in the short direction, FIG. 4B is a partial sectional view of the gas burner 22 in the longitudinal direction, and FIG. 4C schematically shows the gas burner portion. It is a sketch. In these drawings, parts corresponding to those in FIG.

  In this example, a shield 22b is formed so as to surround the air guide tube 22a. A nozzle 22d is provided below the shield 22b, and a gas outlet 22e is provided in a linear shape (long hole) below the air guide tube 22a (on the nozzle 22d side). In addition, in order to make the outflow amount of each site | part of the linear gas outflow port 22e the same, you may make it change the width | variety of a hole according to a place.

  FIG. 5 is a diagram illustrating a second configuration example of the gas burner unit of the semiconductor manufacturing apparatus. The other structural example of the gas burner 22 is shown. 5A is a cross-sectional view of the gas burner 22 in the short direction, and FIG. 5B is a partial cross-sectional view of the gas burner 22 in the longitudinal direction. In both figures, parts corresponding to those in FIG.

  In this example, a shield 22b is formed so as to surround the air guide tube 22a. A nozzle 22d is provided below the shield 22b, and a plurality of gas outlets 22e are provided at equal intervals below the air guide tube 22a (on the nozzle 22d side). In this configuration, in order to make the gas density in the combustion chamber uniform and the flow rate of gas flowing from the nozzle 22d to the outside uniform, the air guide tube 22a can be appropriately moved in the left-right direction in the figure, for example. In addition, in order to fix the air guide tube 22a and make the outflow amount of each part of the gas outlet port 22e the same, the interval of the gas outlet port 22e may be changed depending on the location if necessary.

  FIG. 6 is a diagram illustrating a third configuration example of the gas burner unit of the semiconductor manufacturing apparatus. 6A is a cross-sectional view of the gas burner 22 in the short direction, and FIG. 6B is a partial cross-sectional view of the gas burner 22 in the longitudinal direction. In both figures, parts corresponding to those in FIG.

  Also in this example, the shield 22b is formed so as to surround the air guide tube 22a. Below the shield 22b is a nozzle 22d, and a plurality of gas outlets 22e are spirally provided at equal intervals on the side surface of the air guide tube 22a. In this configuration, in order to make the gas density in the combustion chamber uniform and the flow rate of gas flowing from the nozzle 22d to the outside uniform, the air guide tube 22a is configured to be rotatable as indicated by the arrows in the figure.

  FIG. 7 is a diagram showing the relationship between the height of the nozzle and the pressure of the outflow gas. As shown in FIG. 7A, the pressure of the outflowing combustion gas can be lowered by separating the nozzle 22d from the surface of the substrate 100. Further, as shown in FIG. 7B, the pressure of the outflowing combustion gas can be increased by bringing the nozzle 22d closer to the surface of the substrate 100.

  FIG. 8 is a diagram showing the relationship between the shape and angle of the nozzle and the pressure of the outflow gas. As shown in FIG. 8, the outflow gas pressure can be adjusted by adjusting the shape and posture of the nozzle 22d (for example, adjusting the shape of the outlet and the angle with respect to the substrate). In this example, as shown in FIG. 8A, the shape of the outlet of the nozzle 22d is open to one side. For this reason, when the gas burner 22 is upright, the pressure of the outflowing combustion gas can be lowered. Further, as shown in FIG. 8B, when the gas burner 22 is rotated or inclined, the outlet of the nozzle 22d approaches the surface of the substrate 100, and the pressure of the outflowing combustion gas can be increased.

  FIG. 9 is a diagram illustrating the relationship between the distance between the nozzle and the air guide tube and the pressure of the outflow gas. As shown in FIG. 9, the temperature of the combustion gas flowing out from the nozzle 22d can be adjusted by changing the relative positional relationship between the air guide tube 22a and the shield 22b. For example, it is possible to change the distance between the heat source and the nozzle 22d by moving the combustion chamber 22c so that the air guide tube 22a can move forward and backward in the shield 22b toward the nozzle 22d. In addition, the distance between the heat source and the substrate can be adjusted.

  Therefore, as shown in FIG. 9A, when the air guide tube 22a is relatively close to the nozzle 22d, the combustion gas flowing out from the nozzle 22d becomes relatively high in temperature. Further, as shown in FIG. 9B, when the air guide tube 22a is relatively separated from the nozzle 22d, the combustion gas flowing out from the nozzle 22d has a relatively low temperature.

  Such a structure makes it possible to adjust the temperature of the outflowing combustion gas without changing the gap between the gas burner 22 and the substrate 100, and is good. Of course, the substrate temperature may be adjusted by changing the gap between the gas burner 22 and the substrate. Of course, the gas temperature can be adjusted by changing the gap between the gas burner 22 and the substrate and further adjusting the relative positional relationship between the air guide tube 22a and the shield 22b. Further, the substrate temperature can be adjusted by changing the scanning speed of the gas burner 22 with respect to the substrate.

  The structure of the gas burner shown in FIGS. 4 to 9 can be combined as appropriate.

  For example, the configuration shown in FIG. 7 and the configuration shown in FIG. 9 can be combined. The entire gas burner 22 shown in FIG. 7 is configured to approach or separate from the substrate 100 so that the gap between the nozzle 22d and the substrate 100 can be adjusted, and the temperature (for example, the surface temperature) of the substrate 100 is adjusted. Further, as shown in FIG. 9, the temperature of the substrate 100 is finely adjusted by allowing the air guide tube 22a in the gas burner 22 to advance and retract toward the nozzle 22d. This makes it easier to set the temperature of the substrate 100 to the target heat treatment temperature.

  Further, the configurations shown in FIGS. 7 and 8 can be combined. The gap between the nozzle 22d and the substrate 100 can be adjusted so that the entire gas burner 22 approaches or separates from the substrate 100 (see FIG. 7), and the surface temperature of the substrate 100 and the flame pressure are adjusted. Further, the surface temperature of the substrate 100 and the flame pressure are adjusted by adjusting the attitude of the entire gas burner 22 relative to the substrate 100 (see FIG. 8).

  Further, the configurations shown in FIGS. 7, 8, and 9 can be combined. The gas burner 22 as a whole is moved closer to or away from the substrate 100 so that the gap between the nozzle 22d and the substrate 100 can be adjusted, and the surface temperature of the substrate 100 and the flame pressure are roughly adjusted (see FIG. 7). Further, the flame pressure on the surface of the substrate 100 is adjusted by adjusting the posture of the gas burner 22 with respect to the substrate 100 (see FIG. 8). Further, the surface temperature of the substrate 100 is finely adjusted by enabling the air guide tube 22a in the gas burner 22 to advance and retract toward the nozzle 22d (see FIG. 9). With this configuration, more accurate heat treatment can be performed.

  Although not shown, the shielding plate 22b of the gas burner 22 can be made movable so that the opening (outlet, aperture) of the nozzle 22d can be changed in a wide or narrow direction in the scanning direction of the gas burner 22. Thereby, it is possible to adjust the exposure time of the portion to be processed of the substrate 100 in the scanning direction of the gas burner 22, the temperature profile of the heat treatment of the substrate 100, the heat treatment temperature, the flame pressure, and the like.

  Since the semiconductor manufacturing apparatus described above includes a long gas burner that traverses the substrate, heat treatment of a large-area substrate such as a window glass can be performed. Further, since hydrogen and oxygen as fuel can be obtained by electrolysis of water, it is easy to obtain a gas material and the running cost is low.

  In the semiconductor manufacturing apparatus, the gas burner 22 is provided with the shield 22b. However, the gas burner 22 may be processed in a state where the gas burner 22 is exposed to the outside air without using the shield 22b. Moreover, in the said semiconductor manufacturing apparatus, although the case where combustion gas was ejecting from the shield 22b was demonstrated, you may adjust so that a flame may emerge from the shield 22b.

  Moreover, the process with respect to a board | substrate may be the process by a combustion gas, or the process which makes a flame contact directly. Control of these processes can be appropriately set for each process condition.

  In particular, the flame has a highly reducing inner flame (reducing flame) and a strong oxidizing outer flame (oxidizing flame), and may be set according to the processing conditions depending on which is brought into contact with the substrate. it can. Further, the inner flame is relatively low temperature (about 500 ° C.), and the outer flame is high temperature (about 1400 to 1500 ° C.). The temperature between the inner flame and the outer flame is about 1800 ° C. at a higher temperature. Accordingly, it is possible to make settings according to the processing conditions.

  In the heat treatment step, the reducing atmosphere (hydrogen rich) or the oxidizing atmosphere (oxygen rich) can be easily set by appropriately setting the mixing ratio and supply amount of hydrogen and oxygen.

In addition, since hydrogen and oxygen as fuel are obtained by electrolysis of water, it is possible to easily obtain a mixed gas of 2 mol: 1 mol of hydrogen and oxygen, which is the stoichiometric composition ratio of water (H ₂ O). By adding oxygen or hydrogen separately to the mixed gas, a reducing atmosphere (hydrogen rich) or an oxidizing atmosphere (oxygen rich) can be easily set.

  Also, the flame temperature can be easily adjusted. Further, an inert gas can be introduced if necessary, or the flame state (temperature, gas pressure, etc.) can be adjusted by adjusting the flow rate of the raw material gas.

  Further, it is easy to obtain a desired temperature profile by adjusting the nozzle shape of the gas burner.

  Processing using such a gas burner has high productivity and can be processed at low cost. In addition, since the flame source gas is clean energy such as hydrogen and oxygen, and the main product is water, the environmental load (environmental destruction) can be reduced.

2) Semiconductor Device Manufacturing Method Next, a semiconductor device manufacturing method using the above-described semiconductor manufacturing device will be described with reference to FIGS. 10, 12, and 15 to 17 are process cross-sectional views illustrating the resist removal process (semiconductor device manufacturing method) of the present embodiment. FIG. 11 is a cross-sectional view and a composition diagram showing the resist-affected layer. FIG. 13 is a process cross-sectional view and a reaction formula showing the resist removal process of the present embodiment. FIG. 14 is a process cross-sectional view illustrating the film thickness reduction of the base in the resist removal process. FIG. 18 is a process cross-sectional view illustrating a burst state of the resist film in the resist removal process. FIG. 19 is a cross-sectional view showing how the residue is exhausted by burst.

First, as shown in FIG. 10A, a silicon film 103 is formed as a semiconductor film over a glass substrate (quartz substrate, substrate, transparent substrate, insulating substrate) 100. The silicon film 103 is formed by, for example, a CVD (chemical vapor deposition) method using SiH ₄ (monosilane) gas. Next, heat treatment is performed on the silicon film 103 to recrystallize the silicon to obtain a polycrystalline silicon film. The substrate used may be a silicon substrate, and a base protective film 105 described later may be formed on the silicon substrate.

  Next, a silicon oxide film, for example, is formed as a base protective film (base oxide film, base insulating film) 105 on the silicon film 103. This silicon oxide film is formed by using, for example, a plasma CVD method using TEOS (tetraethyl orthosilicate, tetraethoxysilane), oxygen gas, or the like as a source gas.

  Next, a photoresist film (hereinafter simply referred to as “resist film”) 107 is formed on the base protective film 105, and is exposed and developed (photolithography) to form a resist film (mask film, resist) in a desired shape. (Mask) 107 is left. Next, impurity ions are implanted (ion implantation) into the silicon film 103 using the resist film 107 as a mask. Here, a novolac resin-based photoresist was used. The novolak resin is a resin obtained by condensation polymerization of phenols and aldehydes with an acid.

  As an impurity ion (dopant element), when doping an n-type impurity, for example, a phosphorus compound (yellow phosphorus or phosphine) is implanted, and when doping a p-type impurity, for example, a boron compound (diborane or decaborane) is used. inject. Here, for example, a phosphorus compound is implanted as the n-type impurity.

  As a result, as shown in FIG. 10B, an impurity region 103a is formed in the silicon film 103 where the resist film 107 is not formed. At this time, as shown in the drawing, an altered layer (cured layer) 107a is formed on the surface of the resist film 107 by implanting impurity ions.

  As shown in FIG. 11A, the altered layer 107a includes a normal resist layer (N), a carbonized resist layer (C), and an impurity-doped carbonized resist layer (DC) from the inside. Have

  This carbonized resist layer (C) is a layer in which the carbon atoms of phenol groups constituting the resist film are polymerized, and is a layer harder than the normal resist layer (N). Further, the resist layer (DC) doped with impurities and carbonized is, for example, a layer in which carbons of phenol groups are polymerized via phosphorus (P) as shown in FIG. It is a layer harder than the normal resist layer (N) and the carbonized resist layer (C). This DC layer has a strong P—C bond. Such polymerization (bonding) is formed by ion implantation energy. Therefore, the deteriorated layers (C layer and DC layer) are difficult to remove, and cannot be removed by, for example, dry etching or wet etching alone. Therefore, after dry etching, a strong alkali or strong acid treatment such as ammonia or sulfuric acid is used. Can be finally peeled off. Such a strong bond also occurs when other impurities (for example, boron compounds) are implanted.

  In contrast, in the present embodiment, as shown in FIGS. 12A and 12B, a mixed gas of hydrogen and oxygen is used as a fuel for the resist film 107 on which the altered layer (cured layer) 107a is formed. Since the process using the flame (flame) of the gas burner 22 as a heat source is performed, the resist film 107 can be efficiently removed.

  As for the removal of the resist film 107, ashing (ashing treatment, decomposition treatment, decomposition removal) is generally used. However, the amount of oxygen radicals used in the decomposition reaction is determined by supplying ozone gas, radicals by plasma or the like. Even in a normal ashing apparatus that is activated (activated) and processed, there is a limit in increasing the concentration and improving the reactivity.

  On the other hand, the flame of the gas burner 22 using the mixed gas of hydrogen and oxygen of the present embodiment as a fuel contains a large amount of oxygen radicals (reactive active species). Therefore, the resist film 107 (including the altered layer 107a) can be efficiently removed by bringing the flame into contact with the resist film 107 (including the altered layer 107a) and decomposing (ashing) it.

  In this case, since the oxidation reaction of the resist film is the main reaction, it is considered preferable to contact the flame of the flame.

Further, here, as shown in FIGS. 12A and 13A, a halogen compound gas is further added as a supply gas to the gas burner 22 using a mixed gas of hydrogen and oxygen as the fuel, Perform ashing (removal of altered layer). CF ₄ (carbon tetrafluoride) was added as the halogen compound gas. As shown in the reaction formula (I) in FIG. 13B, this CF ₄ is decomposed by the energy of the flame to generate fluorine radicals (F ^* ). Further, hydrogen fluoride (HF) is formed by the reaction of fluorine (F ₂ ) with water (H ₂ O) which is a reactive product of oxygen and hydrogen (see reaction formula (II)). As the halogen compound gas, CxFy (fluorocarbon, fluorocarbon) other than CF ₄ , hydrofluorocarbon such as SF ₄ , CF ₃ Br, Cl ₂ , and CHF ₃ may be used.

  This fluorine radical is more reactive than the oxygen radical, and the altered layer 107a can be easily vaporized (decomposed and removed). HF is also a strong acid, and it is possible to remove the deteriorated layer 107a. FIG. 13A schematically shows fluorine radicals and by-products (HF) in the flame.

  As described above, according to this embodiment, by adding the halogen compound gas, halogen radicals can be generated, and the altered layer 107a can be easily removed.

  Further, in the present embodiment, as shown in FIG. 12B, after the altered layer 107a is removed, a halogen compound gas is used as a supply gas to the gas burner 22 using a mixed gas of hydrogen and oxygen as a fuel. Is stopped and the oxygen supply is increased. That is, ashing is performed under oxygen-rich conditions.

  First, the reason for stopping the supply of the halogen compound gas (or reducing the addition amount) will be described. It is also possible to continue the supply of the halogen compound gas and remove the resist film 107 under the altered layer 107a. However, in this case, as shown in FIG. 14, not only the resist film 107 but also the base protective film 105 is removed by fluorine radicals or by-products (HF) thereof. Therefore, when the film thickness of the base protective film is reduced and the film thickness is large, the underlying silicon film 103 is further damaged.

  Therefore, in this embodiment mode, after the removal of the deteriorated layer 107a is completed, the addition of the halogen compound gas is stopped to prevent damage to the base protective film 105 and the silicon film 103.

On the other hand, the reason for increasing the supply amount of oxygen gas is to increase the oxygen radicals in the flame and increase the decomposition reaction rate. Here, as for oxygen, the mixed gas ratio of hydrogen and oxygen is adjusted so that the composition ratio of oxygen is larger than 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O).

Here, as described above, since hydrogen and oxygen as fuel are obtained by electrolysis of water, a mixed gas of 2 mol: 1 mol of hydrogen and oxygen, which is the stoichiometric composition ratio of water (H ₂ O), can be easily obtained. By adding oxygen to the mixed gas separately, an oxidizing atmosphere (oxygen rich) can be easily set.

Therefore, the adjustment of the mixed gas in the series of processes is summarized as follows. In the first ashing, as shown in FIG. 15A, a halogen compound gas is added to the mixed gas of hydrogen and oxygen, and the second ashing is performed. As shown in FIG. 15B, the addition of the halogen compound gas is stopped, and the oxygen supply ratio is larger than the stoichiometric composition ratio of water (H ₂ O) of 2 mol: 1 mol. Do in state. Of course, in the second ashing, oxygen and hydrogen may be supplied at a composition ratio of 2 mol: 1 mol which is a stoichiometric composition ratio of water (H ₂ O).

  In order to prevent damage to the underlying protective film 105 and the silicon film 103 due to fluorine radicals or the like, an intake nozzle (hole) 25 for sucking excess radicals may be provided on the outer periphery of the gas burner 22 (see FIG. 16). The intake nozzle 25 is movably installed in conjunction with the gas burner 22. The intake nozzle is connected to, for example, a decompression pump and can adjust the intake (exhaust) speed. By adding such an exhaust system to the manufacturing apparatus and sucking excess radicals to the outer periphery of the gas burner 22, damage to the base protective film 105 and the silicon film 103 can be prevented. The intake hole of the intake nozzle 25 is preferably arranged at a position of 1 to 10 mm from the substrate 1. The distance between the substrate 1 and the intake hole is D1.

In the resist removal step, the resist is removed in two steps of the first and second ashing. However, the third ashing may be further performed in three steps. That is, as shown in FIG. 17, the second ashing is finished in a predetermined period, and the remaining resist film 107 is processed by adjusting the conditions so that the hydroxyl radical (OH ^* ) is rich. As an example of the method for enriching the hydroxyl radical (OH ^* ), the ratio of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) as the supply gas is the stoichiometric composition of water (H ₂ O). Increasing the composition ratio of oxygen to 2 mol: 1 mol (making oxygen rich) is mentioned. It is also conceivable to enrich the hydroxyl radical (OH ^* ) by other methods such as changing the type of supply gas or applying excitation energy to the flame from the outside.

  According to this treatment, the resist film 107 is ashed, and hydroxyl groups (—OH) are attached to the surface thereof, so that the surface of the resist film 107 becomes hydrophilic. Therefore, as shown in FIG. 17B, even if the resist film 107 remains slightly at the end of ashing (third ashing), the remaining resist film 107 is easily removed by subsequent cleaning (for example, washing with water). be able to.

This hydroxyl radical (OH ^* ) is a reactive species of the oxidation reaction (decomposition reaction) and is also deeply involved in the ashing reaction. Therefore, it is preferable that the concentration is large not only for hydrophilic treatment but also for promoting a normal ashing reaction.

Therefore, for example, in dry ashing using oxygen radicals in an ozone atmosphere and ashing using the flame of the present embodiment, the removal rate is considered to be about 3000 kg / mim for the former and about 10,000 kg / mim for the latter. Thus, it is thought that the contribution of the hydroxyl radical (OH ^* ) as the reactive species is also large that the rate is increased.

  The resist removal step is preferably performed with the substrate temperature set to 100 ° C. or lower. This substrate temperature is performed by the temperature adjustment 52 described above (see FIG. 1). The reason for limiting the substrate temperature will be described with reference to FIG.

  As shown in FIG. 18A, at the initial stage of ashing, the altered layer 107a covers the surface of the resist film 107 as described above. Here, when the substrate temperature becomes high, the temperature of the internal resist film 107 rises, and organic substances and the like which are constituent materials thereof are volatilized. At this time, since the surface of the resist film 107 is covered with the hard altered layer 107a, the internal pressure rises and a burst is generated as shown in FIG. When this burst occurs, debris of the altered layer 107a and the resist film 107 adhere to the surface of the base protective film 105 and become a residue (contaminant). In particular, since the altered layer 107a is a film that is difficult to remove, it is difficult to remove the damaged layer 107a after being scattered around by a burst. And ion implantation are hindered, and device characteristics are deteriorated. Therefore, in this embodiment, the burst is prevented by setting the substrate temperature to 100 ° C. or lower.

  Further, when the substrate temperature is set to 100 ° C. or higher, a residue due to the burst may be generated. Therefore, an intake nozzle (hole) 27 as shown in FIG. 19 may be provided. The intake nozzle 27 is installed to be movable in conjunction with the gas burner 22. The intake nozzle is connected to, for example, a decompression pump and can adjust the intake (exhaust) speed. By incorporating such an exhaust system into the manufacturing apparatus, the resist residue can be exhausted, and contamination due to the residue can be reduced. The intake hole of the intake nozzle 25 is preferably arranged at a position of 1 to 10 mm from the substrate 1. The distance between the substrate 1 and the intake hole is D2. The intake nozzle 27 may also serve as the intake nozzle 25 described above. FIG. 19A shows a case where the intake nozzle 27 is arranged in the substantially extending direction of the gas burner 22, and FIG. 19B shows the intake nozzle 27 in a direction perpendicular to the extending direction of the gas burner 22 (substrate 100 In parallel). In the case where such a mechanism is provided, the substrate temperature can be increased, so that ashing of the resist film 107 can be performed at high speed.

  As described above in detail, according to the present embodiment, the resist film can be accurately removed without using a chemical solution or an expensive apparatus.

  The resist film removal method of the present embodiment is applied to, for example, the formation of a low concentration source and drain region when forming a TFT (Thin Film Transistor) having an LDD (Lightly Doped Drain Structure) structure on a glass substrate. Is possible. That is, after forming a gate electrode on a silicon film on a glass substrate, a resist film having a width wider than the gate electrode is formed, and after ion implantation, the resist film is removed. This embodiment mode can be used when the resist film is removed. Thereafter, ion implantation is performed using the gate electrode as a mask to form high concentration source and drain regions.

  In this embodiment, the case where the altered layer 107a is formed on the surface of the resist film 107 during ion implantation has been described. For example, the carbonized resist layer (C) described above is used during plasma etching or the like. Can also be formed. Therefore, the present invention can also be applied to a deteriorated layer of a resist film generated during etching. Of course, the present invention can also be applied to the removal of a resist film in which a deteriorated layer is not formed. In this case, it is not necessary to add a halogen compound gas.

  In this embodiment, a novolak resin-based resist film has been described as an example, but the present invention can also be applied to other resist films. The resist film is an organic resin, and its constituent elements are polymerized in an ion implantation or plasma atmosphere, and a deteriorated layer is easily formed. Therefore, the present invention can be applied not only to removing a novolac resin-based resist film but also to removing a resist film that is an organic compound widely. In particular, the chemically amplified resist film is difficult to remove even when a KrF stepper is used, and the removal efficiency is achieved by reducing the film thickness. According to the present embodiment, it is possible to ash the resist film efficiently even for such chemically amplified resist films.

  In this embodiment, the case where a glass substrate is used as the substrate has been described, but another material substrate (for example, a silicon substrate) may be used. However, the glass substrate is easily subjected to heat stress, and is likely to be distorted and cracked. Therefore, according to the flame of the present embodiment, since it is not necessary to set the entire chamber to a high temperature, it is possible to reduce the thermal stress applied to the entire glass substrate. Therefore, this embodiment is suitable for application.

  The resist film is an indispensable film for manufacturing a semiconductor device (element) such as the above-described TFT, and the resist film removing process is indispensable in the manufacturing process. Therefore, the resist film removal method of the present embodiment can also be applied to a method for manufacturing a semiconductor device and a method for manufacturing an electronic device having the semiconductor device (for example, an electro-optical device using the TFT as a drive element). It is.

  In addition, the examples and application examples described through the embodiments of the invention can be used in combination as appropriate according to the application, or can be used with modifications or improvements. The present invention is described in the description of the embodiments described above. It is not limited.

The figure which shows the structural example of the semiconductor manufacturing apparatus used for manufacture of the semiconductor device of Embodiment 1. Plan view showing a configuration example of a gas burner part of a semiconductor manufacturing apparatus Sectional drawing which shows the structural example of the gas burner part of a semiconductor manufacturing apparatus The figure which shows the 1st structural example of the gas burner part of a semiconductor manufacturing apparatus. The figure which shows the 2nd structural example of the gas burner part of a semiconductor manufacturing apparatus. The figure which shows the 3rd structural example of the gas burner part of a semiconductor manufacturing apparatus. Diagram showing the relationship between nozzle height and effluent gas pressure The figure which shows the relationship between the shape and angle of the nozzle and the pressure of the outflow gas The figure which shows the relationship between the distance between the nozzle and the air guide tube and the substrate temperature Process sectional drawing which shows the resist removal process (manufacturing method of a semiconductor device) of this Embodiment Cross-sectional view and composition diagram showing altered resist layer Process sectional drawing which shows the resist removal process (manufacturing method of a semiconductor device) of this Embodiment The process sectional drawing and reaction figure which show the resist removal process of this Embodiment Process cross-sectional view showing underlayer film reduction in resist removal process Process sectional drawing which shows the resist removal process (manufacturing method of a semiconductor device) of this Embodiment Process sectional drawing which shows the resist removal process (manufacturing method of a semiconductor device) of this Embodiment Process sectional drawing which shows the resist removal process (manufacturing method of a semiconductor device) of this Embodiment Cross-sectional process diagram showing how the resist film bursts during the resist removal process Cross-sectional process diagram showing how residue is exhausted by burst

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Water tank, 12 ... Electrolysis tank, 15 ... Gas controller, 21 ... Chamber (processing chamber), 22 ... Gas burner, 22a ... Air conduit, 22b ... Shielding device, 22c ... Combustion chamber, 22d ... Nozzle, 22e ... Outlet, 25 ... Intake nozzle, 27 ... Intake nozzle, 29 ... Residue, 51 ... Stage part, 100 ... Glass substrate (substrate), 103 ... Silicon film, 103a ... Impurity region, 105 ... Underlayer protection film, N ... Normal resist Layer, C ... carbonized resist layer, DC ... impurity layer doped and carbonized resist layer

Claims (12)

A method for manufacturing a semiconductor device comprising a step of removing a resist film formed on a substrate,
A method of manufacturing a semiconductor device, wherein the resist film is removed by subjecting the resist film to a treatment using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source.   2. The method of manufacturing a semiconductor device according to claim 1, wherein the resist film is used as a mask at the time of impurity ion implantation, and has a modified layer on a surface thereof.   3. The method of manufacturing a semiconductor device according to claim 1, wherein the treatment is performed by further adding a halogen compound gas to the mixed gas.   The method for manufacturing a semiconductor device according to claim 1, wherein the halogen compound gas is a fluorocarbon gas.   5. The method of manufacturing a semiconductor device according to claim 1, wherein the process is performed by scanning a flame of the gas burner relative to the substrate.   The method of manufacturing a semiconductor device according to claim 1, wherein the resist film is removed while the substrate temperature is maintained at 100 ° C. or lower.   The said process is performed while adjusting the said substrate temperature by adjusting the scanning speed of the said gas burner, or the distance of the said board | substrate and the said flame. The manufacturing method of the semiconductor device of description. The processing is as follows:
A treatment using the gas burner in which an exhaust port is formed in the vicinity of a flame,
The method for manufacturing a semiconductor device according to claim 2, wherein the process is performed while sucking debris of the deteriorated layer of the resist film from the exhaust port. A method for manufacturing a semiconductor device, comprising:
(A) implanting impurity ions using a resist film formed on the substrate as a mask;
(B) removing the resist film,
(B1) removing the resist film, comprising: a first step of removing the altered layer formed on the surface of the resist film; and (b2) a second step of removing the resist film inside the altered layer. Have
The step (b1) is a step of performing a first treatment using a flame of a gas burner in which a halogen compound gas is added to a mixed gas of hydrogen and oxygen serving as a fuel as a heat source,
The step (b2) is a method of manufacturing a semiconductor device, wherein the second process is performed using a flame of a gas burner in which the amount of the halogen compound gas added is smaller than that of the first process, as a heat source. The step (b2) is a treatment using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source, and the ratio of the mixed gas of hydrogen and oxygen is the stoichiometric composition of water (H ₂ O). 10. The method for manufacturing a semiconductor device according to claim 9, wherein the process is performed in a state where the composition ratio of oxygen is larger than the ratio of 2 mol: 1 mol. The step (b2)
A process using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source,
A treatment in which oxygen radicals (O ^* ) are richer than when the mixed gas ratio of hydrogen and oxygen is 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O);
Thereafter, the treatment is performed in a state where the hydroxyl radical (OH ^* ) is richer than when the mixed gas ratio of hydrogen and oxygen is 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O). 10. The method of manufacturing a semiconductor device according to claim 9, further comprising: A method of manufacturing an electronic apparatus having a semiconductor device,
The manufacturing method of the electronic device which has a manufacturing method of the semiconductor device as described in any one of Claims 1 thru | or 11.

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