JP2007141891A - Method of manufacturing semiconductor device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulation film having good characteristics, and to improve the characteristics of a semiconductor device. <P>SOLUTION: In manufacturing the semiconductor device (e.g. TFT), a film applied with polysilazane (-(SiH<SB>2</SB>NH)-) used as, for example, an interlayer dielectric is formed on a substrate 100, and thermal processing using a thermal source of flames of a gas burner using a mixed gas of hydrogen and oxygen as a fuel is performed to bake the polysilazane-applied film and to modify the polysilazane conversion SiO<SB>2</SB>. By executing this thermal processing, a conversion reaction is promoted by oxygen radicals (O<SP>*</SP>), hydrogen radicals (H<SP>*</SP>) and hydroxyl group radicals (OH<SP>*</SP>) etc. in or around the flames, a non-conversion portion (remaining Si-N etc.) is reduced and the film quality of the polysilazane conversion SiO<SB>2</SB>can be improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for forming an insulating film used as an interlayer insulating film or the like of a semiconductor device, and particularly to a heat treatment of an insulating liquid material.

  For example, a semiconductor device such as a thin film transistor (TFT) is formed by sequentially forming a semiconductor film constituting a transistor and a conductive film constituting a wiring. Between these layers, an interlayer insulating film is formed to maintain insulation between elements and wirings in each layer.

  Such an interlayer insulating film is required to have not only insulating properties but also a flatness function for reducing unevenness caused by underlying elements and wirings. Therefore, attention has been paid to a siloxane SOG (spin on glass) method in which an interlayer insulating film is formed by applying an insulating liquid material and performing a heat treatment (firing). Note that siloxane refers to a state in which silicon (Si) and oxygen (O) are alternately bonded to form a polymer, and Si—O is referred to as a siloxane bond.

  There are a wide variety of insulating liquid materials, but polysilazane, which will be described in detail later, is dense and highly insulating, has little volume shrinkage (shrinkage) before and after heat treatment, and cracks due to shrinkage even when thickened. Research and development as an interlayer insulating film of a semiconductor device are progressing.

  For example, the following Patent Document 1 (Japanese Patent Laid-Open No. 11-249168) discloses a technique of forming an interlayer insulating film (14) by subjecting a coating film of perhydropolysilazane to water vapor annealing. Further, it is disclosed that this interlayer insulating film (14) contains silicon nitride and silicon hydroxide as unconverted substances in addition to silicon oxide (paragraphs [0037] to [0046]).

Patent Document 2 (Japanese Patent Laid-Open No. 11-345974) also discloses a technique for forming a fired film (PS2) made of SiO ₂ by subjecting a coating film (SP1) of perhydropolysilazane to water vapor annealing. In addition, the code | symbol in parenthesis is a code | symbol in literature.
JP-A-11-249168 JP-A-11-345974

  The present inventor is engaged in research and development of semiconductor devices, and has been intensively studied to improve the characteristics of polysilazane used as an interlayer insulating film.

  As a result of investigation, it has been found that reduction of impurities in the film and reduction of defects are important for improving the film characteristics.

As will be described in detail later, according to the degassing analysis of the present inventor, the presence of —SiN— could be confirmed by detecting NH ₃ from the film. In the presence of such SiN groups, the insulation characteristics deteriorate. This is attributed to a dipole structure due to N in the insulating film, and is considered to be caused by a hysteresis characteristic (charge is accumulated) due to polarization of the dipole.

  Further, defects in the film include O (oxygen atom) defects. When such oxygen vacancies exist, electrons are trapped at such vacancies, particularly at the defects at the film interface. For example, when polysilazane is used as a gate insulating film, the electron mobility is reduced, and transistor characteristics Will be reduced.

  Accordingly, an object of the present invention is to provide an insulating film with good characteristics. It is another object of the present invention to improve the characteristics of a semiconductor device by using an insulating film with favorable characteristics.

  (1) In the method of manufacturing a semiconductor device according to the present invention, the insulating liquid material applied on the substrate is subjected to a heat treatment using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source. A process of forming an insulating film formed by baking the insulating liquid material by promoting hydrolysis of the conductive liquid material.

Since the heat treatment using the flame of the gas burner as the heat source is thus performed, hydrolysis (hydrolysis condensation polymerization reaction) of the insulating liquid material can be promoted, and the insulating liquid material is baked. The film quality of the formed insulating film can be improved. Specifically, the unreacted part in the insulating film can be reduced.
The insulating liquid material is, for example, a compound having a bond of silicon and nitrogen (Si—N).

  The insulating liquid material is, for example, an organic solvent solution in which polysilazane is dissolved in an organic solvent (for example, xylene or the like).

The ratio of hydrogen to oxygen in the mixed gas is, for example, 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O).

The heat treatment is performed in a state where the hydroxyl radical (OH ^* ) is richer than when the ratio of hydrogen and oxygen in the mixed gas is 2 mol: 1 mol, which is the stoichiometric composition ratio of water (H ₂ O), for example.

The heat treatment is performed, for example, in a state where the ratio of hydrogen to oxygen in the mixed gas is larger than the composition ratio of oxygen (2 mol: 1 mol) which is the stoichiometric composition ratio of water (H ₂ O).

  The heat treatment is performed, for example, by scanning the flame of a gas burner relative to the insulating liquid material applied on the substrate.

  The substrate temperature can be adjusted by adjusting the scanning speed of the gas burner.

  (2) A method of manufacturing a semiconductor device according to the present invention includes (a) a step of forming a semiconductor element on a substrate, and (b) a step of forming an insulating film on the semiconductor element, wherein (b1) the semiconductor A step of applying an insulating liquid material on the element; and (b2) heat-treating the insulating liquid material using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source. A step of forming an insulating film formed by firing the liquid material, and (c) a step of forming a wiring on the insulating film.

  Since the heat treatment was performed using the flame of the gas burner as a heat source in this way, hydrolysis of the insulating liquid material can be promoted, and the insulating liquid material is baked and the formed insulating film The film quality can be improved. Specifically, the unreacted part in the insulating film can be reduced. In addition, the insulating property of the (interlayer) insulating film between the semiconductor element and the wiring can be improved, and the flatness of the surface can be improved. Note that a drying step may be provided between the coating step and the heat treatment step.

  The step (b1) is a step of forming an insulating film formed by firing the insulating liquid material by promoting the hydrolysis of the insulating liquid material by the flame of the gas burner.

In the step (b1), for example, the hydroxyl radical (OH ^* ) is richer than when the ratio of hydrogen to oxygen in the mixed gas is 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O). Done.

  (3) A method of manufacturing a semiconductor device of the present invention includes (a) a step of forming a gate insulating film on a substrate, (a1) a step of applying an insulating liquid material on the substrate, and (a2 A step of subjecting the insulating liquid material to a heat treatment using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source to form a gate insulating film formed by firing the insulating liquid material; (C) forming a gate electrode on the gate insulating film; and (d) forming source and drain regions in the substrate on both sides of the gate electrode.

  Since the heat treatment was performed using the flame of the gas burner as a heat source in this way, hydrolysis of the insulating liquid material can be promoted, and the insulating liquid material is baked and the formed gate insulating film The film quality can be improved. Specifically, the unreacted part in the insulating film can be reduced. Further, by improving the characteristics of the gate insulating film, transistor characteristics can also be improved. Moreover, the flatness of the surface can be improved. Note that a drying step may be provided between the coating step and the heat treatment step.

The step (a2) is performed in a state in which oxygen is richer than when, for example, the ratio of hydrogen to oxygen in the mixed gas is 2 mol: 1 mol, which is the stoichiometric composition ratio of water (H ₂ O).

  (4) An electronic apparatus of the present invention includes a semiconductor device manufactured using the above-described method for manufacturing a 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).

<Embodiment 1>
In this embodiment, the insulating film is baked by performing a heat treatment on the coating film coated with the insulating liquid material using a gas burner using a mixed gas of hydrogen and oxygen as a fuel. Modification (reduction of impurities, reduction of defects) is performed.

  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, and the like. 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 entire gas burner 22 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 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 attitude of the entire gas burner 22 relative to the substrate 100 (see FIG. 8). Further, the surface 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 (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 heat treatment step, a reducing atmosphere (hydrogen rich) or an oxidizing atmosphere (oxygen rich) can be easily set by appropriately setting the mixing ratio and supply amount of hydrogen and oxygen. It is easy to adjust the flame temperature. 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.

2) Manufacturing method of semiconductor device (application example to interlayer insulating film)
Next, a method for manufacturing a semiconductor device (TFT) using the above-described semiconductor manufacturing apparatus will be described with reference to FIGS. 10 and 11 are process cross-sectional views illustrating the method for manufacturing the semiconductor device (TFT) of the present embodiment.

  First, as shown in FIG. 10A, on a glass substrate (quartz substrate, substrate, transparent substrate, insulating substrate) 100, for example, a silicon oxide film is formed as a base protective film (base oxide film, base insulating film) 101. About 100 nm is formed. This silicon oxide film is formed by using, for example, a plasma CVD (chemical vapor deposition) method using TEOS (tetraethyl orthosilicate), oxygen gas, or the like as a source gas. The substrate used may be a silicon substrate.

Next, for example, a silicon film 102 is formed as a semiconductor film on the base protective film (base oxide film, base insulating film) 101. This silicon film is formed by, for example, a CVD method using SiH ₄ (monosilane) gas. Next, the silicon film is subjected to heat treatment, and the silicon is recrystallized to form a polycrystalline silicon film (102).

  Next, a photoresist film (not shown) (hereinafter simply referred to as “resist film”) is formed on the silicon film 102, and is exposed and developed (photolithography) to form an island-like resist film (mask film, resist mask). ). Next, using the resist film as a mask, the silicon film 102 is etched to form a semiconductor element region (island region). Hereinafter, this photolithography, etching, and the process of removing a resist film described later are referred to as patterning.

  Next, the resist film is removed by, for example, ashing (ashing), and a silicon oxide film, for example, is formed as a gate insulating film 103 on the silicon film 102 as shown in FIG. This silicon oxide film is formed by plasma CVD using, for example, TEOS and oxygen gas as source gases.

  Next, a metal material such as Al (aluminum) is formed as the conductive film 104 on the gate insulating film 103 by, for example, a sputtering method. Next, the conductive film 104 is patterned into a desired shape, and a gate electrode (gate electrode wiring) G is formed. As the conductive film 104, a refractory metal such as Ta (tantalum) may be used in addition to Al.

Next, source and drain regions 104a and 104b are formed by implanting (doping or implanting) impurity ions into the silicon film 102 using the gate electrode G as a mask. Note that one of 104a and 104b serves as a source region and the other serves as a drain region. Impurity ions are, for example, PH ₃ (hydrogen phosphide) when forming an n-type semiconductor layer, and B ₂ H ₆ (diborane) when forming a p-type semiconductor layer, for example. Ion implantation.

  Next, as illustrated in FIG. 11, an interlayer insulating film 105 is formed on the gate electrode G. The interlayer insulating film 105 is formed by applying an insulating liquid material and performing heat treatment (firing). For example, when a polysilazane solution is used as the insulating liquid material, a silicon oxide film is formed by firing. The polysilazane solution is obtained by dissolving, for example, 20% of polysilazane in an organic solvent (for example, xylene solution).

FIG. 12 shows the structure of polysilazane and its reaction mechanism. As shown in the reaction formula of FIG. 12A, polysilazane is an inorganic polymer soluble in an organic solvent having — (SiH ₂ NH) — as a basic unit, and oxygen (O ₂ ) or water ( It reacts with H ₂ O, water vapor) by heating to form silicon dioxide (SiO ₂ , silica, silicon oxide film). At this time, ammonia (NH ₃ ) and hydrogen (H ₂ ) are released. FIG. 12B shows a bonding state of polysilazane and silicon dioxide.

  When such an insulating liquid material is used, unevenness caused by lower elements and wirings can be reduced and flatness can be improved as compared with film formation by CVD (for example, TEOS film).

In addition, when polysilazane is used, a dense and highly insulating insulating film (SiO ₂ ) can be formed. Furthermore, there is little volume shrinkage (shrinkage) before and after heat treatment, and cracking due to shrinkage occurs even when the film thickness is increased. Therefore, it is suitable for use as an interlayer insulating film.

However, according to the analysis of the present inventor, degassing from a film obtained by applying a polysilazane solution and baking (hereinafter, this film is referred to as “polysilazane-converted SiO ₂ ”) was detected. The results of analysis by a thermal desorption spectroscopy (TDS) apparatus are shown in FIGS. FIG. 13 is a graph showing changes in pressure of gas desorbed from the film with respect to the temperatures of polysilazane-converted SiO ₂ and TEOS. The horizontal axis is the sample upper surface temperature [° C.], the vertical axis is the pressure in the sample chamber, and PS means polysilazane-converted SiO ₂ . As can be seen from the graph, polysilazane-converted SiO ₂ tends to have a higher pressure than TEOS, and the tendency is particularly noticeable near 200 degrees. It can be considered that the increase in pressure is caused by desorbed gas (released gas) from the film.

Based on these results, further studies were conducted and detailed degassing analysis was conducted. FIG. 14 shows the results of degassing analysis of polysilazane-converted SiO ₂ and TEOS. FIG. 14A shows the case of polysilazane-converted SiO ₂ (calcination temperature 350 ° C.), and FIG. 14B shows the case of TEOS. The horizontal axis represents the sample upper surface temperature [° C.], and the vertical axis represents the qualitative strength (Intensity) [au].

As shown in FIG. 14A, degassing of H ₂ , H ₂ O, NH ₃ / OH and O ₂ was detected from the polysilazane-converted SiO ₂ . This is presumably because the reaction (hydrolysis) of polysilazane is not sufficient, and unconverted (unreacted) -SiN- and -SiOH- are present.

In addition, analysis of the FT-IR transmission spectrum of the polysilazane conversion SiO _2, above -SiN- and the presence of -SiOH- could be confirmed. FT-IR (Fourier transform infrared absorption spectroscopy) means a Fourier transform infrared spectrophotometer. FIG. 15 is a graph showing the analysis results of transmission spectra of polysilazane-converted SiO ₂ and TEOS. The horizontal axis represents wavelength (Wavenumber, cm ⁻¹ ), and the vertical axis represents absorbance (Absorbance).

PS indicates polysilazane-converted SiO ₂ , and the temperature means the firing temperature. Further, the TEOS film is formed by the CVD method as described above, and ECR-TEOS in FIG. 15 indicates a TEOS film formed by ECR (electron cyclotron resonance) -CVD.

As shown in FIG. 15, the polysilazane conversion _{SiO 2 (PS-300 ℃,} PS-400 ℃) spectra for Si-N was confirmed. In addition, although it is difficult to discriminate in the graph, as a result of detailed analysis, broad spectra of Si—OH, Si—H, and H ₂ O were confirmed. Therefore, this result from too, polysilazane conversion SiO _2, -SiN- and unconverted, it can be seen that -SiOH- like exist. As for the TEOS film (TEOS, ECR-TEOS), although the spectrum of Si—O appears remarkably similarly to the polysilazane-converted SiO ₂ , the spectra of Si—N, Si—OH, Si—H, and H ₂ O are , Could not be confirmed, or its absorbance was smaller. In addition, in the spectrum of Si—O, three types of expansion / contraction, deflection, and LO mode were confirmed.

  When the SiN group (—SiN—) is present in this manner, polarization is caused by the dipole structure, the CV characteristics (capacitance-capacitance characteristics) cause hysteresis, and the insulating characteristics are deteriorated. In addition, the silicon nitride film has a higher dielectric constant than the oxide film, and the presence of the SiN group increases the dielectric constant, which degrades the device characteristics.

Further, as shown in FIG. 14A, degassing from polysilazane-converted SiO ₂ (particularly NH ₃ / OH or H ₂ O) peaks when the sample upper surface temperature [° C.] is about 180 to 280 ° C. Greet. Therefore, when a treatment at a temperature after the formation of polysilazane-converted SiO ₂ is performed, NH ₃ / OH, H ₂ O, or the like contaminates the treatment chamber (chamber), for example, a film formed by the treatment Cause deterioration of film quality.

FIG. 14B shows TEOS degassing analysis results. As in the case of polysilazane-converted SiO ₂ , degassing of H ₂ , H ₂ O, NH ₃ / OH, and O ₂ was detected. No degassing peak was observed at about 180-280 ° C. as in the case of converted SiO ₂ . Therefore, the problem of contamination due to degassing is more serious in polysilazane-converted SiO ₂ than in TEOS, and countermeasures are important.

Therefore, in this embodiment, in order to improve the film quality of polysilazane-converted SiO ₂ and reduce degassing contamination in the subsequent steps, polysilazane-converted SiO ₂ (interlayer insulating film 105) is formed by the following method.

FIG. 16 is a process sectional view showing a method of forming polysilazane-converted SiO ₂ . As shown in FIG. 16A, a polysilazane solution is applied onto the gate electrode G by a spin coating method to form a polysilazane coating film 105a. The spin coating condition is, for example, about 1500 seconds at 1500 rpm. In addition, you may apply | coat a polysilazane solution using the inkjet method. One application amount is, for example, about 5000 mm (Å = 10 ⁻⁸ cm) on the gate insulating film 103.

  Next, the substrate is mounted on a mounting table (hot plate) (not shown), the plate temperature is controlled so that the substrate upper surface temperature (surface temperature) is about 100 ° C., and the polysilazane coating film 105a is heated for about 1 minute. Dry (volatilize the solvent in the film). Next, the plate temperature is controlled so that the substrate upper surface temperature is about 300 ° C., and heating (intermediate firing, first firing) is performed for about 10 minutes.

  Next, as shown in FIG. 16B, a polysilazane solution is applied onto the polysilazane coating film 105a by a spin coating method to form a polysilazane coating film 105b. The polysilazane coating film 105b is dried and subjected to intermediate firing in the same manner as the polysilazane coating film 105a.

  In this way, by applying the polysilazane solution twice, the polysilazane coating films 105a and 105b of about 1000 to 1100 mm, for example, on the gate insulating film 103 and about 6000 mm on the gate electrode G are formed. In the present embodiment, the number of times of application is two, but the application may be repeated three or more times. In addition, the coating amount may be increased and the number of coatings may be one. However, when the film thickness is large, the flatness of the film can be secured and the film quality can be made uniform by repeating the coating several times.

Next, as shown in FIG. 16C, the substrate 100 is mounted on the stage portion 51 of FIG. 1, and the gas burner 22 is scanned over the substrate 100 (polysilazane coating films 105a and 105b) to perform heat treatment (flame annealing, Final baking and second baking) are performed, and the polysilazane coating films 105a and 105b are fired, and the polysilazane-converted SiO ₂ is modified. As for the flame annealing condition, for example, the substrate upper surface temperature is about 350 ° C. and 5 minutes or less. The substrate upper surface temperature is adjusted by, for example, the scanning speed of the gas burner 22. Here, for example, scanning is performed at a speed of 2 m / sec. In addition, the ratio of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) supplied to the gas burner 22 is, for example, 2 mol: 1 mol which is a stoichiometric composition.

  As described above, according to the present embodiment, since the flame annealing treatment is performed on the polysilazane coating film, the film can be baked in a short time and the film can be modified. Reduction of SiN- or -SiOH- (unconverted part) can be achieved.

  That is, in the case of heat treatment in a normal furnace, firing is required for about 30 minutes to 1 hour even if the temperature in the furnace is set to about 300 ° C. to 400 ° C. The process can be completed in units of several tens of seconds to several minutes (30 minutes or less).

  Next, the reason why the film characteristics are improved will be described. FIG. 17 is a diagram schematically showing a state of flame annealing of the polysilazane coating film.

That is, according to the inventor's study, oxygen radicals (O ^* ) are present in or around the flame in addition to the raw material gases (O ₂ , H ₂ ) and H ₂ O (water vapor) that is a product of combustion. , Hydrogen radicals (H ^* ), hydroxyl radicals (OH ^* ), and the like are considered to exist (see FIG. 17A). These radicals are considered to be generated by, for example, a material gas or water vapor decomposed by the thermal energy of a flame or radicalization of a reaction intermediate.

  Therefore, it is considered that these radicals are also actively involved in the hydrolysis (conversion) reaction of polysilazane described in FIG. 12 to improve the film quality.

That is, as shown in FIG. 17B, source gases (O ₂ , H ₂ ), H ₂ O, oxygen radicals (O ^* ), hydrogen radicals (H ^* ), and hydroxyl radicals (OH) that are reactive species. The molecular size of ^* ) is in the order of O ₂ > H ₂ O> hydroxyl radical (OH ^* )> oxygen radical (O ^* )> H ₂ > hydrogen radical (H ^* ). Accordingly, the diffusion coefficient of these reactive species into the polysilazane coating film is O ₂ <H ₂ O <hydroxyl radical (OH ^* ) <oxygen radical (O ^* ) <H ₂ <hydrogen radical (H ^* ). .

Accordingly, as shown in FIG. 17C, the hydroxyl radical (OH ^* ), oxygen radical (O ^* ) and hydrogen radical (H ^* ) are more easily diffused into the film than O ₂ and H ₂ O. It is considered that the conversion reaction is promoted at the center and bottom of the membrane. As a result, it is considered that unconverted parts are reduced and the film quality of polysilazane-converted SiO ₂ is improved. The ease of diffusion of these radicals into the film is thought to contribute to the reduction of the processing time described above. In addition, since radicals are excited unstable substances, their reaction speed is fast, which contributes to shortening of processing time.

  It should be noted that since the firing and modification of the film are expected to proceed in parallel, it is difficult to clearly separate these treatments. Flame annealing may be performed.

In addition, regarding the hydrolysis (conversion) reaction, the hydroxyl radical (OH ^* ) among the above radicals is considered to contribute to the promotion of the reaction. Therefore, it is preferable to adjust the conditions so that the hydroxyl radical (OH ^* ) becomes rich during the flame annealing. 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.

Thus, according to the present embodiment, a good interlayer insulating film 105 (polysilazane converted SiO ₂ ) can be obtained.

  Next, as shown in FIG. 18, the interlayer insulating film 105 is patterned to form contact holes on the source and drain regions 104a and 104b. FIG. 18 is a final process cross-sectional view illustrating the method for manufacturing the semiconductor device (TFT) of the present embodiment.

  Next, for example, ITO (indium tin oxide film) is formed as the conductive film 106 on the interlayer insulating film 105 including the inside of the contact hole by a sputtering method. As the conductive film 106, in addition to ITO, a metal material such as Al, Mo (molybdenum), or Cu (copper) may be used. Next, the conductive film 106 is patterned into a desired shape to form source and drain electrodes (source, drain lead electrode, lead wiring) 106a and 106b. Note that one of 106a and 106b serves as a source electrode, and the other serves as a drain electrode.

  The TFT is almost completed through the above steps.

  In the present embodiment, the intermediate firing (first firing) is a heat treatment using a hot plate (300 ° C., about 10 minutes), but this heat treatment may also be the above-described flame annealing.

  In the present embodiment, the present invention is applied to the interlayer insulating film on the gate electrode G. However, the present invention is not limited to this film. For example, the insulating film formed on the source and drain electrodes 106a and 106b. The present invention may be applied to a film. Further, the present invention may be applied to the base protective film 101. Further, the present invention may be applied to the gate insulating film 103. An application example to the gate insulating film will be described in detail in Embodiment 2.

  In this embodiment, the TFT has been described as an example. However, the present invention is not limited to such an element, and can be widely applied to a method for manufacturing a semiconductor device using an insulating liquid material.

<Embodiment 2>
Although the present invention is applied to the interlayer insulating film in Embodiment 1, the present invention may be applied to the gate insulating film 103.

  FIG. 19 is a process sectional view showing the method for manufacturing the semiconductor device (TFT) of this embodiment. In addition, the same code | symbol is attached | subjected to the site | part corresponding to Embodiment 1, and repeated description of the formation process etc. is abbreviate | omitted.

  As shown in FIG. 19A, a base protective film 101 and a silicon film 102 are formed over a glass substrate 100 as in the first embodiment.

Next, a polysilazane solution is applied onto the silicon film 102 by a spin coating method to form a polysilazane coating film 103a. The spin coating condition is, for example, about 1500 seconds at 1500 rpm. In addition, you may apply | coat a polysilazane solution using the inkjet method. A single coating amount is, for example, about 5000 mm (10 ⁻⁸ cm) on the silicon film 102.

  Next, the substrate is mounted on a mounting table (hot plate) (not shown) and heated at 100 ° C. for about 1 minute to dry the polysilazane coating film (volatilizes the solvent in the film). Next, intermediate firing (first firing) is performed as in the first embodiment.

Next, as shown in FIG. 19B, the substrate 100 is mounted on the stage portion 51 of FIG. 1, and a heat treatment (flame annealing, firing) is performed by scanning the gas burner 22 on the substrate 100 to obtain a polysilazane coating film. 103a is fired and polysilazane-converted SiO ₂ is modified. As for the flame annealing condition, for example, the substrate upper surface temperature is about 350 ° C. and 5 minutes or less. The substrate upper surface temperature is adjusted by, for example, the scanning speed of the gas burner 22. Here, for example, scanning is performed at a speed of 2 m / sec. The ratio of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) supplied to the gas burner 22 is, for example, a state in which the ratio of oxygen is larger than the stoichiometric composition of 2 mol: 1 mol (oxygen rich state). ).

  As described above, since the flame annealing is performed in this embodiment, the gate insulating film 103 is baked in a short time as described in detail with reference to FIG. The membrane can be modified. Furthermore, in this embodiment, since the flame annealing is performed in an oxygen-rich state, oxygen vacancies in the gate insulating film can be compensated. As a result, electron traps due to oxygen defects can be reduced, electron mobility of the channel can be improved, and transistor characteristics can be improved.

  Next, as shown in FIG. 19C, the gate electrode G and the source / drain regions 104a and 104b on the gate insulating film 103 are formed in the same manner as in the first embodiment. Next, an interlayer insulating film 105 is formed on the gate electrode G. This interlayer insulating film 105 is also formed in the same manner as in the first embodiment. Next, as in Embodiment 1, source and drain electrodes (source, drain lead electrode, lead wiring) 106a and 106b are formed. The TFT is almost completed through the above steps.

Note that the interlayer insulating film 105 may be a TEOS film. However, by using polysilazane-converted SiO ₂ for each layer of the gate insulating film 103 and the interlayer insulating film 105 as in the present embodiment, steps due to the silicon film 102 and the gate electrode G can be reduced and the flatness is improved. Can be made.
<Description of electro-optical device and electronic device>
Next, an electro-optical device and an electronic device in which the semiconductor device (for example, TFT) formed by the method described in the above embodiment is used will be described.

  The aforementioned semiconductor device (for example, TFT) is used as a drive element of an electro-optical device (display device), for example. FIG. 20 shows an example of an electronic apparatus using the electro-optical device of the invention. FIG. 20A shows an application example to a mobile phone, and FIG. 20B shows an application example to a video camera. 20C illustrates an example of application to television (TV), and FIG. 20D illustrates an example of application to roll-up television.

  As shown in FIG. 20A, the mobile phone 530 includes an antenna portion 531, an audio output portion 532, an audio input portion 533, an operation portion 534, and an electro-optical device (display portion) 500. The electro-optical device of the present invention can be used for this electro-optical device.

  As shown in FIG. 20B, the video camera 540 includes an image receiving unit 541, an operation unit 542, an audio input unit 543, and an electro-optical device (display unit) 500. The electro-optical device of the present invention can be used for this electro-optical device.

  As illustrated in FIG. 20C, the television 550 includes an electro-optical device (display unit) 500. The electro-optical device of the present invention can be used for this electro-optical device. The electro-optical device of the present invention can also be used for a monitor device (electro-optical device) used in a personal computer or the like.

  As illustrated in FIG. 20D, the roll-up television 560 includes an electro-optical device (display unit) 500. The electro-optical device of the present invention can be used for this electro-optical device.

  In addition to the above, electronic devices having electro-optical devices include large screens, personal computers, portable information devices (so-called PDAs, electronic notebooks), etc., and fax machines with display functions, digital camera finders, mobile phones, etc. Various types such as a type TV, an electric bulletin board, and an advertising display are included.

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 manufacturing method of the semiconductor device (TFT) of Embodiment 1 Process sectional drawing which shows the manufacturing method of the semiconductor device (TFT) of Embodiment 1 Diagram showing the structure of polysilazane and its reaction mechanism Figure showing the change in pressure of the film with respect to the temperature of polysilazane converted SiO ₂ and TEOS (graph) Shows a degassing analysis of the polysilazane conversion SiO ₂ and TEOS (graph) It shows the analysis result of the transmission spectrum of the polysilazane conversion SiO ₂ and TEOS (graph) Process sectional drawing which shows the formation method of polysilazane conversion SiO ₂ A diagram schematically showing the state of flame annealing of a polysilazane coating film Final process sectional view showing a method of manufacturing the semiconductor device (TFT) of the first embodiment Process sectional drawing which shows the manufacturing method of the semiconductor device (TFT) of Embodiment 2 FIG. 10 is a diagram illustrating an example of an electronic apparatus using the electro-optical device of the invention.

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 51, stage portion, 100 glass substrate (substrate), 101 protective film 102, silicon film 103 gate insulating film 103a polysilazane coating film 104 conductive film 104a, 104b source , Drain region, 105 ... interlayer insulating film, 105 a and 105 b ... polysilazane coating film, 106 ... conductive film, 106 a and 106 b ... source and drain electrodes, 500 ... electro-optical device, 530 ... mobile phone, 531 ... antenna part, 532 ... voice output unit, 533 ... voice input unit, 534 ... operation unit, 540 ... video camera, 541 ... image receiving unit, 542 ... Work unit, 543 ... voice input section, 550 ... television, 560 ... roll-up television, G ... gate electrode, PS ... polysilazane conversion SiO ₂

Claims (14)

A method for manufacturing a semiconductor device, comprising:
By subjecting the insulating liquid material applied on the substrate to a heat treatment using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source, and promoting hydrolysis of the insulating liquid material, A method of manufacturing a semiconductor device, comprising a step of forming an insulating film formed by firing the insulating liquid material.   The method for manufacturing a semiconductor device according to claim 1, wherein the insulating liquid material is a compound having a bond of silicon and nitrogen (Si—N).   2. The method of manufacturing a semiconductor device according to claim 1, wherein the insulating liquid material is an organic solvent solution of polysilazane. _{2. The} method of manufacturing a semiconductor device according to claim 1, wherein in the heat treatment, a ratio of hydrogen and oxygen in the mixed gas is set to 2 mol: 1 mol which is a stoichiometric composition ratio of water (H ₂ O). The heat treatment is performed in a state where the hydroxyl radical (OH ^* ) is richer than when the ratio of hydrogen to oxygen in the mixed gas is 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O). The method of manufacturing a semiconductor device according to claim 1. The heat treatment is performed in a state where the ratio of hydrogen to oxygen in the mixed gas is larger than the stoichiometric composition ratio of water (H ₂ O), which is 2 mol: 1 mol, of oxygen. The manufacturing method of the semiconductor device of description.   2. The method of manufacturing a semiconductor device according to claim 1, wherein the heat treatment is performed by scanning a flame of the gas burner relative to an insulating liquid material applied on the substrate.   The method of manufacturing a semiconductor device according to claim 7, wherein the substrate temperature is adjusted by adjusting a scanning speed of the gas burner. A method for manufacturing a semiconductor device, comprising:
(A) forming a semiconductor element on the substrate;
(B) forming an insulating film on the semiconductor element,
(B1) applying an insulating liquid material on the semiconductor element;
(B2) The insulating liquid material is subjected to a heat treatment using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source to form an insulating film formed by firing the insulating liquid material. When,
(C) forming a wiring on the insulating film;
A method for manufacturing a semiconductor device, comprising:   The step (b1) is a step of forming an insulating film formed by firing the insulating liquid material by promoting hydrolysis of the insulating liquid material by a flame of the gas burner. A method for manufacturing a semiconductor device according to claim 9. In the step (b1), the ratio of hydrogen to oxygen in the mixed gas is 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O), and the hydroxyl radical (OH ^* ) is more rich. 10. The method for manufacturing a semiconductor device according to claim 9, wherein the method is performed. A method for manufacturing a semiconductor device, comprising:
(A) forming a gate insulating film on the substrate,
(A1) applying an insulating liquid material on the substrate;
(A2) The insulating liquid material is subjected to heat treatment using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source to form a gate insulating film formed by firing the insulating liquid material. Process,
(B) forming a gate electrode on the gate insulating film;
(C) forming source and drain regions in the substrate on both sides of the gate electrode;
A method for manufacturing a semiconductor device, comprising: The step (a2) is performed in a state in which oxygen is richer than when the ratio of hydrogen to oxygen in the mixed gas is 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O). A method for manufacturing a semiconductor device according to claim 12. An electronic apparatus comprising a semiconductor device manufactured using the method for manufacturing a semiconductor device according to claim 1.

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