Method for depositing doped silicon oxide film and vapor deposition equipment

Abstract

The invention belongs to the technical field of semiconductor production, and relates to a method for depositing a doped silicon oxide film and vapor deposition equipment, the method comprises the following steps: (1) introducing a doped element precursor, thermally decomposing the doped element precursor and adsorbing the doped element precursor on the surface of a substrate, and then carrying out first purging; (2) introducing a silicon precursor to enable the silicon precursor to be adsorbed on the surface of the substrate, and then performing second purging; (3) carrying out oxidation reaction on the oxygen source, the decomposer of the doped element precursor and the silicon precursor, and then carrying out third purging; and the step (1) to the step (3) are circulated until the doped silicon oxide thin film with the target thickness is generated on the surface of the substrate. According to the method, the doped element precursor is decomposed, and the decomposed product reacts with the silicon precursor and the oxygen source, so that deposition of the doped silicon oxide thin film on the substrate is promoted, the doped silicon oxide thin film is deposited by using a thermal ALD means, and the doped silicon oxide thin film can be deposited by using a plasma enhanced ALD means.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor production, and in particular to a method for depositing a doped silicon oxide film and a vapor deposition device. Background Art

[0002] With the continuous increase in chip integration, high-aspect-ratio Fin Field-Effect Transistors (FinFETs) have become a key technology in the 7nm node process. Phosphorus or boron doping is an essential step in FinFET manufacturing. Traditionally, phosphorus or boron doping is typically performed using ion implantation, but this method faces numerous challenges at 7nm and below. First, as FinFET dimensions continue to shrink, lattice damage caused by the ion implantation process becomes increasingly severe and difficult to avoid. Second, at a reasonable ion implantation mask height, the extremely small spacing between the N-type and P-type regions limits the implant tilt angle to within 7°, significantly increasing the process complexity. Furthermore, the controllability of the short-channel effect limits the maximum allowable ion implant energy, making doping the FinFET bottom region at a small angle extremely difficult.

[0003] In response to the problems existing in ion implantation, the industry has proposed using annealing to allow phosphorus or boron to enter FinFET. Generally speaking, a layer of phosphorus doped silicate glass (PSG) or boron doped silicate glass (BSG) is first deposited on the substrate by chemical vapor deposition (CVD), and then a protective layer is deposited on the PSG or BSG to prevent the loss of phosphorus or boron during the annealing process. Finally, annealing is used to allow the phosphorus in PSG or the boron in BSG to enter the substrate under thermal drive, thereby achieving phosphorus or boron doping in the silicon substrate. This method can effectively avoid the problems existing in the ion implantation method.

[0004] For advanced processes, as chip dimensions continue to shrink, traditional CVD-deposited films can no longer meet device requirements for conformality and step coverage. Therefore, atomic layer deposition (ALD) is required to deposit PSG or BSG films. Thermal ALD and plasma-enhanced ALD are the more commonly used ALD methods.

[0005] Currently, thermal ALD processes cannot be used to deposit PSG or BSG films.

[0006] While research on plasma-enhanced ALD (ALD) deposition of PSG thin films has been conducted, as chip sizes decrease and device structures become more complex, the uneven distribution of plasma in the ALD process can easily lead to inconsistent film thickness and composition, affecting conformality. Furthermore, some phosphorus-containing compound precursors are difficult to react with the ALD process, making them incapable of forming PSG thin films using the ALD process. This demonstrates that currently, plasma-enhanced ALD is difficult to produce highly conformal PSG or BSG thin films, and the choice of precursors is limited.

[0007] In summary, there is an urgent need to provide a method for depositing PSG or BSG films to address the limitations of traditional processes. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for depositing doped silicon oxide films and a vapor deposition device, which realizes the deposition of doped silicon oxide films using thermal ALD means, and the method can also deposit doped silicon oxide films by plasma-enhanced ALD means.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for depositing a doped silicon oxide film, the method comprising the following steps:

[0011] (1) introducing a doping element precursor, causing it to thermally decompose and adsorb on the substrate surface, and then performing a first purge;

[0012] (2) introducing a silicon precursor to allow it to adsorb on the substrate surface, and then performing a second purge;

[0013] (3) The oxygen source undergoes an oxidation reaction with the decomposition product of the doping element precursor and the silicon precursor, and then a third purge is performed.

[0014] Steps (1) to (3) are repeated until a doped silicon oxide film of target thickness is formed on the surface of the substrate.

[0015] The method for depositing a doped silicon oxide film provided by the present invention thermally decomposes a doping element precursor, which then reacts with a silicon precursor and an oxygen source to deposit the doped silicon oxide film on a substrate. This method enables the deposition of doped silicon oxide films using thermal ALD and is also capable of depositing doped silicon oxide films using plasma-enhanced ALD, broadening the range of precursor options available in the plasma-enhanced ALD process.

[0016] Preferably, before the doping element precursor is introduced in step (1), the reaction temperature is controlled to be no lower than the thermal decomposition temperature of the doping element precursor.

[0017] Preferably, the reaction temperature is 320-340°C, for example, 320°C, 325°C, 330°C, 335°C or 340°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] Preferably, before the doping element precursor is introduced in step (1), the reaction pressure is controlled to be 1.5-2.5 Torr, for example, it can be 1.5 Torr, 1.8 Torr, 2 Torr, 2.2 Torr or 2.5 Torr, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0019] Preferably, the doping element precursor in step (1) includes a phosphorus precursor or a boron precursor.

[0020] The phosphorus precursor includes phosphane and / or phosphate compounds.

[0021] The boron precursor includes borane and / or borate ester compounds.

[0022] When the doping element precursor is a phosphorus precursor, a PSG film of target thickness is generated on the substrate surface; when the doping element precursor is a boron precursor, a BSG film of target thickness is generated on the substrate surface.

[0023] Preferably, the phosphate compound includes triethyl phosphate and / or trimethyl phosphite. Preferably, the borate compound includes triethyl borate and / or trimethyl borate.

[0024] It should be noted that the present invention does not impose any specific restrictions on the time for introducing the doping element precursor in step (1) and the time for introducing the silicon precursor in step (2). Those skilled in the art can make adaptive adjustments based on the usage scenario and application conditions. There is no specific restriction on the time for the first purge in step (1), the time for the second purge in step (2), and the time for the third purge in step (3), so as to achieve the required cleanliness of the substrate surface and meet the requirements of the next deposition.

[0025] The first purge in step (1) can remove excess doping element precursor and decomposition products; the second purge in step (2) can remove excess silicon precursor; and the third purge in step (3) can remove by-products and excess reactants produced by the oxidation reaction.

[0026] Preferably, the first purge in step (1), the second purge in step (2), and the third purge in step (3) are all performed using inert gas.

[0027] Preferably, the inert gas comprises at least one of nitrogen, helium or argon. Typical but non-limiting combinations include a combination of nitrogen and helium, a combination of helium and argon, and a combination of nitrogen and argon.

[0028] Preferably, the silicon precursor in step (2) includes an aminosilane compound.

[0029] The aminosilane compound includes any one of BDEAS (bis(diethylamino)silane), DIPAS (diisopropylamine silane) or BTBAS (bis(tert-butylamino)silane) or a combination of at least two thereof. Typical but non-limiting combinations include a combination of BDEAS and DIPAS, a combination of DIPAS and BTBAS, or a combination of BDEAS, DIPAS and BTBAS.

[0030] In a second aspect, the present invention provides a method for depositing a doped silicon oxide film using a thermal atomic layer deposition process, the method comprising the method for depositing a doped silicon oxide film described in the first aspect. Specifically, the method comprises: in step (3), introducing an oxygen source to react with a decomposition product of a doping element precursor and a silicon precursor.

[0031] In the present invention, a thermal ALD method is used to carry out the oxidation reaction. In step (3), an oxygen source is introduced into the reaction chamber. The oxygen source reacts with the decomposition products of the doping element precursor and the silicon precursor to form a doped silicon oxide film.

[0032] Preferably, the flow rate of the oxygen source is 1.8-2.2 slpm, and the introduction time is 1.8-2.2 s.

[0033] The flow rate of the oxygen source is 1.8-2.2 slpm, for example, 1.8 slpm, 1.9 slpm, 2 slpm, 2.1 slpm or 2.2 slpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] The oxygen source introduction time is 1.8-2.2 s, for example, 1.8 s, 1.9 s, 2 s, 2.1 s or 2.2 s, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] Preferably, the oxygen source comprises O3.

[0036] In a third aspect, the present invention provides a method for depositing a doped silicon oxide film using a plasma-enhanced atomic layer deposition process, the method comprising the method for depositing a doped silicon oxide film described in the first aspect. Specifically, the method comprises: continuously introducing an oxygen source during steps (1) to (3), and after the second purge in step (2), generating an oxygen source plasma by ionization, and reacting the oxygen source plasma with decomposition products of the doping element precursor and the silicon precursor.

[0037] The flow rate of the oxygen source is 1.8-2.2 slpm, for example, 1.8 slpm, 1.9 slpm, 2 slpm, 2.1 slpm or 2.2 slpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] In the present invention, a plasma-enhanced ALD method is used to carry out the oxidation reaction. An oxygen source is continuously introduced throughout the entire process. At the same time, after the second purge in step (2), an oxygen source plasma is generated by ionization, thereby reacting with the decomposition products of the doping element precursor and the silicon precursor to form a doped silicon oxide film.

[0039] Preferably, the oxygen source comprises at least one of O3, O2, H2O or H2O2, typical but non-limiting combinations include a combination of O3 and O2, a combination of H2O and O2, a combination of O3 and H2O, a combination of H2O2 and O2, and a combination of O3 and H2O2.

[0040] Preferably, the ionization comprises radio frequency ignition.

[0041] The discharge power of the radio frequency ignition is 50-500W, and the discharge time is 0.4-0.6s.

[0042] The discharge power of the radio frequency ignition is 50-500W, for example, 50W, 100W, 200W, 300W, 400W or 500W, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] The discharge time of the radio frequency ignition is 0.4-0.6s, for example, 0.4s, 0.45s, 0.5s, 0.55s or 0.6s, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] Preferably, after the doped silicon oxide film of target thickness is generated, a protective layer is deposited on the surface of the doped silicon oxide film.

[0045] The step of depositing the protective layer can prevent the loss of phosphorus or boron during the subsequent annealing process.

[0046] The present invention has no special limitation on the steps and processes for depositing the protective layer, and the steps and processes well known to those skilled in the art can be used, which will not be described in detail here.

[0047] In a fourth aspect, the present invention provides a vapor deposition apparatus for depositing a doped silicon oxide film using a thermal atomic layer deposition process, wherein the vapor deposition apparatus is used to perform the method for depositing a doped silicon oxide film using a thermal atomic layer deposition process as described in the second aspect, wherein the vapor deposition apparatus includes a reaction chamber, wherein the reaction chamber includes:

[0048] A gas inlet assembly for inputting precursors, oxygen sources and inert gases;

[0049] a base for placing the substrate;

[0050] The tail exhaust assembly is used to exhaust the gas in the reaction chamber.

[0051] In a fifth aspect, the present invention provides a vapor deposition apparatus for depositing a doped silicon oxide film using a plasma enhanced atomic layer deposition process, wherein the vapor deposition apparatus is used to perform the method for depositing a doped silicon oxide film using a plasma enhanced atomic layer deposition process as described in the second aspect, wherein the vapor deposition apparatus includes a reaction chamber, wherein the reaction chamber includes:

[0052] A gas inlet assembly for inputting precursors, oxygen sources and inert gases;

[0053] A plasma generating assembly for generating plasma;

[0054] a base for placing the substrate;

[0055] The tail exhaust assembly is used to exhaust the gas in the reaction chamber.

[0056] Those skilled in the art will appreciate that a vapor deposition apparatus for depositing a doped silicon oxide film using a plasma enhanced atomic layer deposition process has an ionization device.

[0057] When the plasma enhanced ALD method is used to deposit the doped silicon oxide film in the present invention, the ionization device is turned on and operated.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] (1) The method for depositing a doped silicon oxide film provided by the present invention thermally decomposes a doping element precursor, and the decomposition product then reacts with a silicon precursor and an oxygen source, thereby promoting the deposition of the doped silicon oxide film on a substrate. The method first decomposes the doping element precursor, and then uses the decomposition product to participate in the reaction and deposit on the substrate surface. Due to the high reactivity of the decomposition product, the problem of low reactivity of phosphorus precursors or boron precursors and their difficulty in reacting in the thermal ALD process is overcome, thereby realizing the deposition of a doped silicon oxide film by means of thermal ALD. Moreover, due to the good conformality of the thermal ALD process, the present invention can also obtain a PSG film or BSG film with high conformality.

[0060] (2) The method for depositing a doped silicon oxide film provided by the present invention can also be used to deposit a doped silicon oxide film by plasma-enhanced ALD. For phosphorus precursors that are difficult to react in plasma-enhanced ALD, the range of precursor selection for plasma-enhanced ALD is broadened by first decomposing the precursors and then using the decomposition products to participate in the reaction and deposit them on the substrate surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a structural schematic diagram of a thermal atomic layer deposition device for depositing doped silicon oxide films using a thermal atomic layer deposition process provided in a specific embodiment of the present invention.

[0062] Figure 2 It is a structural schematic diagram of a plasma enhanced atomic layer deposition device for depositing doped silicon oxide thin films using a plasma enhanced atomic layer deposition process provided by a specific embodiment of the present invention.

[0063] Among them: 1, reaction chamber; 2, precursor inlet; 3, oxygen source inlet; 4, inert gas inlet; 5, substrate; 6, heater; 7, tail exhaust assembly; 8, radio frequency ionization device.

[0064] Figure 3 This is a thickness distribution diagram of the base film in the product prepared in Example 1.

[0065] Figure 4 This is the infrared and comparative analysis spectrum of the base film in the product prepared in Example 1.

[0066] Figure 5 This is the XPS phosphorus scanning spectrum of the base film in the product prepared in Example 1.

[0067] Figure 6 This is a thickness distribution diagram of the base film in the product prepared in Example 6.

[0068] Figure 7 This is the XPS phosphorus scanning spectrum of the base film in the product prepared in Example 6. DETAILED DESCRIPTION

[0069] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0070] like Figure 1 As shown, the following embodiments or comparative examples are for depositing a doped silicon oxide film on the substrate surface in the reaction chamber. Taking the thermal ALD process as an example, the structural schematic diagram of the thermal atomic layer deposition device used for depositing the doped silicon oxide film is shown in FIG. Figure 1 As shown, the vapor deposition equipment includes a reaction chamber 1, and the reaction chamber 1 includes: an air intake assembly for inputting a precursor, an oxygen source and an inert gas, the air intake assembly including a precursor inlet 2, an oxygen source inlet 3 and an inert gas inlet 4; a base for placing a substrate 5, and a heater 6 is provided on the non-deposition surface of the substrate 5; and a tail exhaust assembly 7 for discharging the gas in the reaction chamber 1.

[0071] like Figure 2 As shown, the following embodiments or comparative examples are for depositing a doped silicon oxide film on the substrate surface in the reaction chamber. Taking the plasma enhanced ALD process as an example, the structural schematic diagram of the plasma enhanced atomic layer deposition device used for depositing the doped silicon oxide film is shown in FIG. Figure 2 As shown, the vapor deposition equipment includes a reaction chamber 1, and the reaction chamber 1 includes: an air intake assembly for inputting a precursor, an oxygen source and an inert gas, the air intake assembly including a precursor inlet 2, an oxygen source inlet 3 and an inert gas inlet 4; a base for placing a substrate 5, the non-deposition surface of the substrate 5 is provided with a heater 6; and a tail exhaust assembly 7 for exhausting the gas in the reaction chamber 1; the reaction chamber 1 is connected to a radio frequency ionization device 8, and the radio frequency ionization device 8 is turned on and operated when the plasma enhanced ALD method is used to deposit the doped silicon oxide film.

[0072] The specific embodiments and comparative examples of the thermal atomic layer deposition process are described in detail below.

[0073] Example 1

[0074] This embodiment provides a method for depositing a doped silicon oxide film using a thermal atomic layer deposition process, the method comprising the following steps:

[0075] (1) The substrate is transported into the reaction chamber and the reaction temperature is controlled to 330° C. Specifically, the susceptor temperature is increased to 330° C. The reaction pressure is controlled to 1.5 Torr. Specifically, the pressure of the reaction chamber is increased to 1.5 Torr.

[0076] (2) Triethyl phosphate was introduced for 0.5 s to allow it to thermally decompose and adsorb on the substrate surface, and then nitrogen was used for a first purge of 0.5 s.

[0077] (3) BDEAS was introduced for 0.5 s to allow it to adsorb on the substrate surface, and then nitrogen was used for a second purge for 0.5 s.

[0078] (4) O3 was introduced at a flow rate of 2 slpm for 2 s, and then nitrogen was used for a third purge of 2 s.

[0079] The cycle from step (2) to step (4) was repeated 100 times. In step (4), O3 underwent an oxidation reaction with the decomposition product of triethyl phosphate and BDEAS.

[0080] Then, step (3) to step (4) is cycled 35 times, and in step (4), O3 undergoes an oxidation reaction with BDEAS.

[0081] The thickness graph of the base film (12-inch wafer) of the product obtained in this embodiment is as follows Figure 3 As shown, different colors represent different thicknesses in Å, so different color distributions can show the thickness distribution in different areas. According to the calculation formula of the film in-plane unevenness, WIWNU(1σ)%=1.46% can be calculated.

[0082] The product film obtained in this example was subjected to infrared detection and compared with the infrared spectra of silicon oxide and phosphorus pentoxide. The infrared spectra and comparative analysis diagrams are shown in FIG. Figure 4 As shown, from Figure 4 It can be seen that the infrared absorption curve of this embodiment includes the Si—O bond absorption peak of the silicon oxide film and the PO bond absorption peak of phosphorus pentoxide, indicating that a P-doped silicon oxide film is obtained in this embodiment.

[0083] The product film obtained in this example was subjected to XPS detection, and the results showed that the phosphorus doping amount was 10.91% (atomic percentage), wherein the detection spectrum of P2p is as follows: Figure 5 As shown, from Figure 5 It can be seen that the product film obtained in this example has an obvious P peak, which verifies that the product film obtained in this example is doped with P element.

[0084] Example 2

[0085] This embodiment provides a method for depositing a doped silicon oxide film using a thermal atomic layer deposition process, the method comprising the following steps:

[0086] (1) The substrate is transported into the reaction chamber and the reaction temperature is controlled to 320°C; specifically, the susceptor temperature is increased to 320°C. The reaction pressure is controlled to 2.0 Torr; specifically, the pressure of the reaction chamber is increased to 2.0 Torr.

[0087] (2) Trimethyl phosphite was introduced for 0.4 s to cause it to thermally decompose and adsorb on the substrate surface, and then argon was used for a first purge of 0.4 s.

[0088] (3) DIPAS was introduced for 0.4 s to allow it to adsorb on the substrate surface, and then a second purge was performed with argon for 0.4 s.

[0089] (4) O3 was introduced at a flow rate of 1.8 slpm for 2.2 s, and then argon was used for a third purge of 1.8 s.

[0090] The cycle from step (2) to step (4) was repeated 110 times. In step (4), O3 underwent an oxidation reaction with the decomposition product of trimethyl phosphite and DIPAS.

[0091] Then, step (3) to step (4) was cycled 35 times, and in step (4), O3 and DIPAS were oxidized.

[0092] Example 3

[0093] This embodiment provides a method for depositing a doped silicon oxide film using a thermal atomic layer deposition process, the method comprising the following steps:

[0094] (1) The substrate is transported into the reaction chamber and the reaction temperature is controlled to 340°C; specifically, the susceptor temperature is increased to 340°C. The reaction pressure is controlled to 2.5 Torr; specifically, the pressure of the reaction chamber is increased to 2.5 Torr.

[0095] (2) Triethyl borate was introduced for 0.6 s to allow it to thermally decompose and adsorb on the substrate surface, and then helium was used for a first purge for 0.6 s.

[0096] (3) BTBAS was introduced for 0.6 s to allow it to adsorb on the surface of the substrate 5, and then a second purge was performed with helium for 0.6 s.

[0097] (4) O3 was introduced at a flow rate of 2.2 slpm for 1.8 s, and then helium was used for a third purge of 2.2 s.

[0098] The steps (2) to (4) were cycled 90 times. In the cycle (4), O3 reacted with the decomposition product of triethyl borate and BTBAS for oxidation.

[0099] Then, the process of step (3) to step (4) was repeated 35 times, wherein in step (4), O3 and BTBAS were oxidized.

[0100] Example 4

[0101] This embodiment provides a method for depositing a doped silicon oxide film using a thermal atomic layer deposition process. The difference from Example 1 is that steps (2) to (4) are cycled 500 times, and then steps (3) to (4) are cycled 35 times. The rest is the same as Example 1.

[0102] Example 5

[0103] This embodiment provides a method for depositing a doped silicon oxide film using a thermal atomic layer deposition process. The difference from Example 1 is that, except for adjusting the flow rate of O3 in step (3) to 1 slpm and keeping the introduction time unchanged, the rest is the same as Example 1.

[0104] Comparative Example 1

[0105] This comparative example provides a method for depositing a doped silicon oxide film using a thermal atomic layer deposition process. The difference from Example 1 is that the step of introducing O3 is moved between the introduction of triethyl phosphate and BDEAS, and the rest is the same as Example 1.

[0106] Steps (2) to (4) specifically include:

[0107] (2) Triethyl phosphate was introduced for 0.5 s to allow it to thermally decompose and adsorb on the substrate surface, and then nitrogen was used for a first purge of 0.5 s.

[0108] (3) O3 was introduced at a flow rate of 2 slpm for 2 s, and then nitrogen was used for a third purge of 2 s.

[0109] (4) BDEAS was introduced for 0.5 s to allow it to adsorb on the substrate surface, and then nitrogen was used for a second purge for 0.5 s;

[0110] The cycle from step (2) to step (4) is repeated 100 times. In this cycle, O3 in step (3) undergoes an oxidation reaction with the decomposition product of triethyl phosphate.

[0111] Then loop steps (3) and (4) 35 times.

[0112] Comparative Example 2

[0113] This comparative example provides a method for depositing a doped silicon oxide film using a thermal atomic layer deposition process. The difference from Example 1 is that, except for the step of introducing O3 between the introduction of triethyl phosphate and BDEAS, the rest is the same as Example 1.

[0114] Steps (2) to (4) are replaced with:

[0115] (2) Triethyl phosphate was introduced for 0.5 s to allow it to thermally decompose and adsorb on the substrate surface, and then nitrogen was used for a first purge of 0.5 s.

[0116] (3) O3 was introduced at a flow rate of 2 slpm for 2 s, and then nitrogen was used for a third purge of 2 s.

[0117] (4) BDEAS was introduced for 0.5 s to allow it to adsorb on the substrate surface, and then nitrogen was used for a second purge for 0.5 s.

[0118] (5) O3 was introduced at a flow rate of 2 slpm for 2 s, and then nitrogen was used for a third purge for 2 s.

[0119] The steps (2) to (5) are cycled 100 times, wherein in step (3), O3 reacts with the decomposition product of triethyl phosphate to undergo an oxidation reaction.

[0120] Then, steps (4) and (5) were cycled 35 times, and in step (5), O3 and BDEAS were oxidized.

[0121] Comparative Example 3

[0122] This comparative example provides a method for depositing a doped silicon oxide film using a thermal atomic layer deposition process. The difference from Example 1 is that the reaction temperature is controlled to be 190°C; specifically, the base temperature is raised to 190°C (the decomposition temperature of triethyl phosphate is above 200°C), that is, after the triethyl phosphate is introduced in step (2), it does not undergo thermal decomposition. Otherwise, the method is the same as Example 1.

[0123] Comparative Example 4

[0124] This comparative example provides a method for depositing a doped silicon oxide film using a thermal atomic layer deposition process. The difference from Example 1 is that step (2) is cycled 500 times, and then steps (3) to (4) are cycled 35 times. The rest is the same as Example 1.

[0125] The specific embodiments and comparative examples of the plasma enhanced atomic layer deposition process are described in detail below.

[0126] Example 6

[0127] This embodiment provides a method for depositing a doped silicon oxide film using a plasma enhanced atomic layer deposition process, the method comprising the following steps:

[0128] (1) The substrate was transported into the reaction chamber and O2 was introduced at a flow rate of 1.8 slpm. The reaction temperature was controlled to 330°C; specifically, the susceptor temperature was increased to 330°C. The reaction pressure was controlled to 1.5 Torr; specifically, the pressure of the reaction chamber was increased to 1.5 Torr.

[0129] (2) O2 was continuously introduced at a flow rate of 1.8 slpm; triethyl phosphate was introduced for 0.5 s to cause it to thermally decompose and adsorb on the substrate surface, and then nitrogen was used for a first purge of 0.5 s.

[0130] (3) O2 was continuously introduced at a flow rate of 1.8 slpm; BDEAS was introduced for 0.5 s to allow it to adsorb on the substrate surface, and then nitrogen was used for a second purge of 0.5 s.

[0131] (4) O2 was continuously introduced at a flow rate of 1.8 slpm; oxygen plasma was generated by radio frequency ignition with a discharge power of 500 W and a discharge time of 0.4 s, and then a third purge of 0.18 s was performed using nitrogen.

[0132] The cycle from step (2) to step (4) was repeated 110 times. In step (4), the oxygen plasma underwent an oxidation reaction with the decomposition products of triethyl phosphate and BDEAS.

[0133] Then, the steps (3) to (4) were cycled 35 times, wherein in step (4), oxygen plasma and BDEAS underwent oxidation reaction.

[0134] The thickness graph of the base film (12-inch wafer) of the product obtained in this embodiment is as follows Figure 6 As shown, different colors represent different thicknesses in Å. The thickness distribution in different areas can be seen from the different color distributions. According to the calculation formula of the film in-plane unevenness, WIWNU(1σ)%=0.53% can be calculated.

[0135] The product film obtained in this example was subjected to XPS detection, and the results showed that the phosphorus doping amount was 12.36% (atomic percentage), wherein the detection spectrum of P2p is as follows: Figure 7 As shown, from Figure 7 It can be seen that the product film obtained in this example has an obvious P peak, which verifies that the product film obtained in this example is doped with P element.

[0136] Example 7

[0137] This embodiment provides a method for depositing a doped silicon oxide film using a plasma enhanced atomic layer deposition process, the method comprising the following steps:

[0138] (1) The substrate was transported into the reaction chamber and O2 was introduced at a flow rate of 2.0 slpm. The reaction temperature was controlled to 340°C; specifically, the susceptor temperature was increased to 340°C. The reaction pressure was controlled to 2.0 Torr; specifically, the pressure of the reaction chamber was increased to 2.0 Torr.

[0139] (2) O2 was continuously introduced at a flow rate of 2.0 slpm; trimethyl phosphite was introduced for 0.6 s to cause it to thermally decompose and adsorb on the substrate surface, and then nitrogen was used for a first purge of 0.6 s.

[0140] (3) O2 was continuously introduced at a flow rate of 2.0 slpm; DIPAS was introduced for 0.6 s to allow it to adsorb on the substrate surface, and then nitrogen was used for a second purge of 0.6 s.

[0141] (4) O2 was continuously introduced at a flow rate of 2.0 slpm; oxygen plasma was generated by radio frequency ignition with a discharge power of 450 W and a discharge time of 0.5 s, and then a third purge of 0.20 s was performed using nitrogen.

[0142] The steps (2) to (4) were cycled 80 times. In the step (4), the oxygen plasma underwent an oxidation reaction with the decomposition products of trimethyl phosphite and DIPAS.

[0143] Then, step (3) to step (4) was cycled 35 times, wherein oxygen plasma and DIPAS were oxidized in step (4).

[0144] Example 8

[0145] This embodiment provides a method for depositing a doped silicon oxide film using a plasma enhanced atomic layer deposition process, the method comprising the following steps:

[0146] (1) The substrate was transported into the reaction chamber and O2 was introduced at a flow rate of 2.2 slpm. The reaction temperature was controlled to 320°C; specifically, the susceptor temperature was increased to 320°C. The reaction pressure was controlled to 2.5 Torr; specifically, the pressure of the reaction chamber was increased to 2.5 Torr.

[0147] (2) O2 was continuously introduced at a flow rate of 2.2 slpm; trimethyl borate was introduced for 0.5 s to cause it to thermally decompose and adsorb on the substrate surface, and then nitrogen was used for a first purge of 0.5 s.

[0148] (3) O2 was continuously introduced at a flow rate of 2.2 slpm; BTBAS was introduced for 0.6 s to allow it to adsorb on the substrate surface, and then nitrogen was used for a second purge of 0.6 s.

[0149] (4) O2 was continuously introduced at a flow rate of 2.2 slpm; oxygen plasma was generated by radio frequency ignition with a discharge power of 50 W and a discharge time of 0.6 s, and then a third purge of 0.22 s was performed using nitrogen.

[0150] The cycle from step (2) to step (4) was repeated 100 times. In step (4), the oxygen plasma underwent an oxidation reaction with the decomposition product of trimethyl borate and BTBAS.

[0151] Then, step (3) to step (4) was cycled 40 times, and in step (4), oxygen plasma and BTBAS were oxidized.

[0152] Example 9

[0153] This embodiment provides a method for depositing a doped silicon oxide film using a plasma enhanced atomic layer deposition process. The difference from Example 6 is that, except for replacing O2 with O3, the rest is the same as Example 6.

[0154] Comparative Example 5

[0155] This comparative example provides a method for depositing a doped silicon oxide film using a plasma-enhanced atomic layer deposition process. The difference from Example 6 is that the step of generating oxygen plasma by radio frequency ignition is moved to between the introduction of triethyl phosphate and BDEAS. The rest is the same as Example 6.

[0156] Steps (2) to (4) specifically include:

[0157] (2) O2 was continuously introduced at a flow rate of 1.8 slpm; triethyl phosphate was introduced for 0.5 s to cause it to thermally decompose and adsorb on the substrate surface, and then nitrogen was used for a first purge of 0.5 s.

[0158] (3) O2 was continuously introduced at a flow rate of 1.8 slpm; oxygen plasma was generated by radio frequency ignition with a discharge power of 500 W and a discharge time of 0.4 s, and then a third purge of 0.18 s was performed using nitrogen.

[0159] (4) O2 was continuously introduced at a flow rate of 1.8 slpm; BDEAS was introduced for 0.5 s to allow it to adsorb on the substrate surface, and then nitrogen was used for a second purge of 0.5 s.

[0160] The cycle from step (2) to step (4) was repeated 100 times, wherein in step (3) of the cycle, the oxygen plasma reacted with the decomposition product of triethyl phosphate to cause an oxidation reaction.

[0161] Then, repeat steps (3) to (4) 35 times.

[0162] Comparative Example 6

[0163] This comparative example provides a method for depositing a doped silicon oxide film using a plasma-enhanced atomic layer deposition process. The difference from Example 6 is that radio frequency ignition is added between the introduction of triethyl phosphate and BDEAS to generate oxygen plasma, and the rest is the same as Example 6.

[0164] Steps (2) to (4) are replaced with:

[0165] (2) O2 was continuously introduced at a flow rate of 1.8 slpm; triethyl phosphate was introduced for 0.5 s to cause it to thermally decompose and adsorb on the substrate surface, and then nitrogen was used for a first purge of 0.5 s.

[0166] (3) O2 was continuously introduced at a flow rate of 1.8 slpm; oxygen plasma was generated by radio frequency ignition with a discharge power of 500 W and a discharge time of 0.4 s, and then a third purge of 0.18 s was performed using nitrogen.

[0167] (4) O2 was continuously introduced at a flow rate of 1.8 slpm; BDEAS was introduced for 0.5 s to allow it to adsorb on the substrate surface, and then nitrogen was used for a second purge of 0.5 s.

[0168] (5) O2 was continuously introduced at a flow rate of 1.8 slpm; oxygen plasma was generated by radio frequency ignition with a discharge power of 500 W and a discharge time of 0.4 s, and then a third purge of 0.18 s was performed using nitrogen.

[0169] The steps (2) to (5) were cycled 100 times, wherein the oxygen plasma in step (3) was oxidized by the decomposition product of triethyl phosphate.

[0170] Then, the steps (4) to (5) were cycled 35 times, wherein in step (5), oxygen plasma and BDEAS were oxidized.

[0171] Comparative Example 7

[0172] This comparative example provides a method for depositing a doped silicon oxide film using a plasma enhanced atomic layer deposition process. The difference from Example 6 is that the reaction temperature is controlled to be 190°C; specifically, the base temperature is raised to 190°C (the decomposition temperature of triethyl phosphate is above 200°C), that is, after the triethyl phosphate is introduced in step (2), it does not undergo thermal decomposition. Otherwise, everything else is the same as Example 6.

[0173] Test method:

[0174] Film Thickness Measurement: Film thickness was measured using an ellipsometer. Film thickness was measured at 49 evenly distributed points on the products obtained in the above examples and comparative examples. The average thickness was calculated to obtain the total thickness of the base film. Here, THK (thickness of the doped silicon oxide film) = THK (total thickness of the base film) - THK (thickness of the silicon oxide). The thickness of the silicon oxide can be calculated by multiplying its single-cycle growth thickness by the number of cycles (GPC (growth per cycle)) × number of cycles. The silicon oxide is the surface layer. The thickness of the doped silicon oxide film is the total thickness of the base film minus the thickness of the silicon oxide.

[0175] Film surface unevenness: According to the 49 film thickness data measured at the above 49 points X i The calculation formula of film in-plane unevenness %WIWNU (1σ) is shown in the following formulas (1) and (2):

[0176] Formula (1);

[0177] Formula (2).

[0178] Where σ is the standard deviation of the film thickness test, X i is the film thickness test result at point i, is the average value of the film thickness test results of all points, n is the number of test points, and n is 49 in the present invention.

[0179] It should be noted that, under the same number of cycles, the thicker the doped silicon oxide film, the better the deposition effect of the doped silicon oxide film. That is, the thicker the doped silicon oxide film obtained in a single cycle, the better the deposition effect. To this end, the present invention divides the thickness of the doped silicon oxide film obtained after the cycle by the number of cycles to obtain the thickness of the doped silicon oxide film deposited in a single cycle. When the thickness of the doped silicon oxide film deposited in a single cycle is ≥0.5 Å, it is recorded as a large amount of deposition, indicating that the doped silicon oxide film is easier to form and more doping elements can combine with Si and O. If it is less than 0.5 Å, it is not a large amount of deposition.

[0180] Doped silicon oxide films were deposited using the methods provided in Examples 1-9 and Comparative Examples 1-7, wherein the total thickness of the substrate film, the thickness of silicon oxide, the thickness of the doped silicon oxide film, the thickness of the doped silicon oxide film deposited in a single cycle, and whether a large amount of deposition was performed are shown in Table 1.

[0181] Table 1

[0182] The following points can be seen from Table 1:

[0183] (1) Analysis of examples

[0184] From Examples 1 to 9, it can be seen that the method for depositing doped silicon oxide films provided by the present invention first decomposes the doping element precursor, and the decomposition products obtained have high reactivity. These decomposition products can react with the silicon precursor and the oxygen source in both thermal atomic layer deposition and plasma enhanced atomic layer deposition. Therefore, this method can utilize thermal atomic layer deposition and plasma enhanced atomic layer deposition to prepare doped silicon oxide films.

[0185] Furthermore, for the deposition process of the doped silicon oxide film, the thickness of the doped silicon oxide film deposited in a single cycle is above 0.540 Å / cycle, and the preparation of a thick doped silicon oxide film can be achieved. In Examples 1 and 4, the temperature is appropriately selected and the flow rate and time of the oxygen source are optimized. In step (4), the oxidation reaction of O3 with the decomposition product of triethyl phosphate and BDEAS is more effective. The thickness of the doped silicon oxide film deposited in a single cycle is above 2.06 Å / cycle, and the deposition effect is optimal.

[0186] By comparing Example 1 with Example 4, it can be seen that different doped silicon oxide film thicknesses can be obtained with different numbers of cycles, and the thickness of the doped silicon oxide film increases basically linearly with the increase in the number of cycles. In practical applications, the number of cyclic deposition times can be adaptively selected according to the product's requirements for the thickness of the doped silicon oxide film.

[0187] By comparing Example 1 with Example 5, it can be seen that the results of Example 5 show that the thickness of the doped silicon oxide film deposited in a single cycle is only 0.540Å / cycle. It takes a lot of time to deposit a thick doped silicon oxide film on a substrate, and the production efficiency is relatively low. This is because the flow rate of O3 in Example 5 is too low, resulting in a significant decrease in the oxidation reaction effect compared to Example 1. This shows that the present invention controls the flow rate of the oxygen source within a reasonable range, has a better oxidation reaction effect, and ultimately the deposition effect of the doped silicon oxide film is better.

[0188] From the comparison between Example 6 and Example 9, it can be seen that the method for depositing doped silicon oxide film by the plasma enhanced atomic layer deposition process provided by the present invention uses different oxygen sources, and a large amount of doped silicon oxide film can also be deposited on the surface of the substrate. In practical applications, different oxygen sources can be selected according to actual needs.

[0189] (2) Comparative analysis For the thermal atomic layer deposition process, it can be seen from the comparison between Example 1 and Comparative Example 1 that the thickness of the doped silicon oxide film deposited in a single cycle in Comparative Example 1 is 0.250 Å / cycle, which is significantly lower than that in Example 1. This is because in Comparative Example 1, the O3 introduced after the introduction of triethyl phosphate will react with the thermal decomposition product of triethyl phosphate, and the reaction product produced by the reaction cannot react with BDEAS, thereby causing the reaction in step (4) to be unable to continue and a large amount of PSG film cannot be deposited.

[0190] Comparing Example 1 and Comparative Example 2, it can be seen that in Comparative Example 2, O3 is first reacted with the thermal decomposition product of triethyl phosphate, and then BDEAS is reacted with O3 in one cycle. The results show that the thickness of the doped silicon oxide film deposited in a single cycle in Comparative Example 2 is 0.210 Å / cycle, which is significantly lower than that in Example 1. This is because the product of the reaction of O3 with the thermal decomposition product of triethyl phosphate in Comparative Example 2 is difficult to form a phosphorus-containing substance on the substrate surface, resulting in difficulty in depositing a large amount of doped silicon oxide film.

[0191] By comparing Example 1 and Comparative Example 3, it can be seen that the thickness of the doped silicon oxide film deposited in a single cycle in Comparative Example 3 is 0.03 Å / cycle, and deposition is almost impossible. This is because the decomposition temperature of the precursor is not reached in Comparative Example 3, which makes it difficult for the precursor to participate in the oxidation reaction in large quantities in step (4), and the silicon oxide film cannot be doped in large quantities.

[0192] By comparing Example 1 and Comparative Example 4, it can be seen that the thickness of the doped silicon oxide film deposited in a single cycle of Comparative Example 4 is 0.248 Å / cycle, the deposition rate is slow, and large-scale deposition cannot be achieved. This is because in Comparative Example 4, sufficient decomposition products are first accumulated on the substrate surface, but the decomposition products do not react with BDEAS during the 500 cycles, resulting in poor deposition effect. This shows that the present invention first decomposes the doping element precursor and then reacts the decomposition products with the silicon precursor and the oxygen source in the same cycle to achieve large-scale deposition of the doped silicon oxide film.

[0193] For plasma enhanced atomic layer deposition process,

[0194] By comparing Example 6 with Comparative Example 5, it can be seen that the thickness of the doped silicon oxide film deposited in a single cycle in Comparative Example 5 is 0.220 Å / cycle, which is significantly lower than that in Example 6. This is because in Comparative Example 5, radio frequency ignition is performed between the introduction of triethyl phosphate and BDEAS to generate oxygen plasma, and the products produced by the thermal decomposition of triethyl phosphate will react with the oxygen plasma in step (3), while the reaction products produced by the reaction cannot react with BDEAS, thereby causing the reaction in step (4) to be unable to continue and a large amount of PSG film cannot be deposited.

[0195] By comparing Example 6 and Comparative Example 6, it can be seen that in Comparative Example 6, oxygen plasma is first reacted with the thermal decomposition products of triethyl phosphate, and then BDEAS is reacted with oxygen plasma in one cycle. The results show that the thickness of the doped silicon oxide film deposited in a single cycle in Comparative Example 6 is 0.190 Å / cycle, which is significantly lower than that in Example 6. This is because the product of the reaction between oxygen plasma and the thermal decomposition products of triethyl phosphate in Comparative Example 6 is difficult to form a phosphorus-containing substance on the substrate surface, resulting in difficulty in depositing a large amount of doped silicon oxide film.

[0196] By comparing Example 6 and Comparative Example 7, it can be seen that the thickness of the doped silicon oxide film deposited in a single cycle in Comparative Example 7 is 0.02 Å / cycle, and deposition is almost impossible. This is because the decomposition temperature of the precursor is not reached in Comparative Example 7, which makes it difficult for the precursor to participate in the oxidation reaction in large quantities in step (4), and the silicon oxide film cannot be doped in large quantities.

[0197] In summary, the method for depositing doped silicon oxide film provided by the present invention causes the doping element precursor to thermally decompose, and the decomposition products then react with the silicon precursor and the oxygen source. The decomposition products have high reaction activity, thereby promoting the deposition of doped silicon oxide film on the substrate surface in both thermal ALD process and plasma enhanced process, thereby achieving large-scale deposition of doped silicon oxide film.

[0198] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for depositing a doped silicon oxide film, characterized in that: The method comprises the following steps: (1) introducing a doping element precursor, causing it to thermally decompose and adsorb on the substrate surface, and then performing a first purge; (2) introducing a silicon precursor to allow it to adsorb on the substrate surface, and then performing a second purge; (3) The oxygen source reacts with the decomposition product of the doping element precursor and the silicon precursor to undergo an oxidation reaction, and then a third purge is performed; Steps (1) to (3) are repeated until a doped silicon oxide film of target thickness is formed on the surface of the substrate.

2. The method for depositing a doped silicon oxide film according to claim 1, wherein: Before the doping element precursor is introduced in step (1), the reaction temperature is controlled to be no lower than the thermal decomposition temperature of the doping element precursor.

3. The method for depositing a doped silicon oxide film according to claim 1, wherein: The doping element precursor in step (1) includes a phosphorus precursor or a boron precursor; The phosphorus precursor includes phosphane and / or phosphate compounds; The boron precursor includes borane and / or borate ester compounds.

4. The method for depositing a doped silicon oxide film according to claim 1, wherein: The silicon precursor in step (2) includes an aminosilane compound; The aminosilane compound includes any one of BDEAS, DIPAS or BTBAS, or a combination of at least two of them.

5. A method for depositing a doped silicon oxide film using a thermal atomic layer deposition process, characterized in that: The method comprises the method for depositing a doped silicon oxide thin film according to any one of claims 1 to 4; The method comprises: In step (3), an oxygen source is introduced to react with the decomposition product of the doping element precursor and the silicon precursor.

6. The method for depositing a doped silicon oxide film by a thermal atomic layer deposition process according to claim 5, characterized in that: The flow rate of the oxygen source is 1.8-2.2 slpm, and the introduction time is 1.8-2.2 s.

7. A method for depositing a doped silicon oxide film using a plasma enhanced atomic layer deposition process, characterized in that: The method comprises the method for depositing a doped silicon oxide thin film according to any one of claims 1 to 4; The method comprises: The oxygen source is continuously introduced during steps (1) to (3), and after the second purge in step (2), an oxygen source plasma is generated by ionization to react with the decomposition products of the doping element precursor and the silicon precursor.

8. The method for depositing a doped silicon oxide film using a plasma enhanced atomic layer deposition process according to claim 7, wherein: The flow rate of the oxygen source is 1.8-2.2 slpm; The ionization includes radio frequency ignition; The discharge power of the radio frequency ignition is 50-500W, and the discharge time is 0.4-0.6s.

9. A vapor deposition apparatus for depositing doped silicon oxide thin films using a thermal atomic layer deposition process, characterized in that: The vapor deposition device is used to perform the method for depositing a doped silicon oxide film by a thermal atomic layer deposition process as claimed in claim 5 or 6, and the vapor deposition device includes a reaction chamber, and the reaction chamber includes: A gas inlet assembly for inputting precursors, oxygen sources and inert gases; a base for placing the substrate; The tail exhaust assembly is used to exhaust the gas in the reaction chamber.

10. A vapor deposition apparatus for depositing doped silicon oxide thin films using a plasma enhanced atomic layer deposition process, characterized in that: The vapor deposition apparatus is used to perform the method for depositing a doped silicon oxide film by a plasma enhanced atomic layer deposition process as claimed in claim 7 or 8, wherein the vapor deposition apparatus comprises a reaction chamber, wherein the reaction chamber comprises: A gas inlet assembly for inputting precursors, oxygen sources and inert gases; A plasma generating assembly for generating plasma; a base for placing the substrate; The tail exhaust assembly is used to exhaust the gas in the reaction chamber.

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