Method of forming a structure comprising a silicon nitride layer

Abstract

A method of forming a structure including a silicon nitride layer is disclosed. An exemplary method includes using high frequency power and low frequency power during deposition and / or processing of the silicon nitride layer to form a film having desired properties. In some cases, the high and / or low frequency power is pulsed on and off to provide additional ability to tune the desired properties.

Description

Technical Field

[0001] This disclosure generally relates to methods for forming thin films and structures including thin films. More specifically, this disclosure relates to methods for forming structures including silicon nitride layers, structures including such layers, and systems for forming such layers. Background Technology

[0002] Silicon nitride (SiN) materials can be used in a wide variety of applications. For example, during the fabrication of electronic devices, silicon nitride can be used to form insulating layers, etch stop layers, spacers, and so on.

[0003] For many applications, it may be desirable to deposit SiN on the surface of a substrate at relatively low temperatures (e.g., less than 650°C). Plasma-enhanced chemical vapor deposition (PECVD) can be used to deposit SiN layers on the substrate surface at relatively low temperatures.

[0004] Typical PECVD techniques for depositing SiN layers involve the use of silicon precursors and reactants. The reactants are typically used to form a plasma. The activated material formed by the plasma can react with the silicon precursor or its derivatives to form SiN. While these techniques work well for some applications, the properties of SiN layers formed using activated materials from typical plasma formation techniques may not allow for desired etch selectivity and / or other properties, such as surface roughness, density, stress, and / or composition. Additionally, or alternatively, such techniques can be relatively time-consuming. Therefore, improved methods are needed for forming SiN-containing structures.

[0005] Any discussion set forth in this section (including discussions of problems and solutions) is included in this disclosure and is for the purpose of providing background to this disclosure only. Such discussion should not be construed as an admission that any or all information was known at the time of making this invention or otherwise constitutes prior art. Summary of the Invention

[0006] Various embodiments of this disclosure relate to methods for forming structures including silicon nitride layers. While various embodiments of this disclosure address the shortcomings of existing methods and structures in more detail below, in general, various embodiments of this disclosure provide improved methods for forming SiN layers with desired properties (e.g., desired etch resistance, desired composition, desired stress, desired density, desired roughness (or smoothness), etc.). Alternatively or additionally, exemplary methods provide relatively efficient processes for forming structures comprising SiN layers.

[0007] According to embodiments of this disclosure, a method of forming a structure including a silicon nitride layer includes: providing a substrate in a reaction chamber of a reactor; providing a silicon precursor in the reaction chamber; providing a first nitrogen-containing reactant in the reaction chamber; and forming a plasma in the reaction chamber while providing one or more of the silicon precursor and the nitrogen-containing reactant. According to various examples of these embodiments, forming the plasma includes providing a first plasma power to electrodes in the reaction chamber while providing one or more of the silicon precursor and the first nitrogen-containing reactant, and providing a second plasma power to electrodes in the reaction chamber while providing one or more of the silicon precursor and the first nitrogen-containing reactant, wherein the frequency of the first plasma power is greater than the frequency of the second plasma power. According to examples of this disclosure, the frequency of the first plasma power is greater than 1 MHz, greater than 10 MHz, or between about 50 MHz and about 200 MHz. The frequency of the second plasma power is less than 5 MHz, less than 1 MHz, or between about 100 kHz and about 2 MHz. According to another example, the second plasma power is pulsed at a pulse frequency. The second plasma power pulse frequency may be, for example, between about 50 Hz and about 5 kHz. The duty cycle of the second plasma power may be between about 1% and about 50% or between about 1% and about 20%. Providing and pulsed second plasma power allows for the formation of plasmas with desired properties (e.g., greater than 2.8 g / cm³). 3 The silicon nitride layer exhibits a high density and relatively low hydrogen content and / or relatively low surface roughness—for example, less than 0.5 nm RMS as measured by atomic force microscopy. Alternatively or additionally, the first plasma power may be pulsed. The pulse frequency of the first plasma power may be between about 50 Hz and about 100 Hz. The duty cycle of the first plasma power may be between about 1% and about 90%, or between about 1% and about 20%. The power of the first plasma power may be at least 2 times or at least 10 times the power of the second plasma power. According to further examples of these embodiments, the silicon precursor comprises a silane. According to a further example, the first nitrogen-containing reactant comprises one or more of nitrogen (N2), ammonia (NH3), hydrazine (N2H4), or triazine (N3H5). Exemplary methods may further include the step of providing a second nitrogen-containing reactant. The second nitrogen-containing reactant may be or include one or more of ammonia (NH3), hydrazine (N2H4), or triazine (N3H5). In some cases, and according to other examples, the flow rate ratio of the first nitrogen-containing reactant to the silicon precursor is greater than 25, greater than 50, or between about 1500 and about 2000. In some cases, the ratio of atomic N to atomic silicon provided by the reactants and precursors is greater than 25, greater than 50, or between about 2000 and about 40000. The method may also include the step of providing a hydrogen-containing reactant to the reaction chamber. The flow rate ratio of the hydrogen reactant to the silicon precursor may be greater than 5 or between about 80 and about 800.

[0008] In some cases, the method may include treating the deposited material. In some cases, the step of treating the deposited material includes forming a plasma. In an example of this case, the treatment steps include providing a treatment gas for a period of time and applying pulsed treatment plasma power for a period of time.

[0009] According to another exemplary embodiment of this disclosure, a structure includes a layer comprising SiN. The structure can be formed using, for example, the methods described herein.

[0010] According to another embodiment, a reactor system is provided. An exemplary reactor system includes a reaction chamber, a precursor source coupled to the reaction chamber, a process gas source coupled to the reaction chamber, one or more reactant sources coupled to the reaction chamber, and a controller. The controller may be configured to perform the methods described herein. The reactor system may include multiple reaction chambers. One or more steps performed by the controller may be performed in one or more of the multiple reaction chambers.

[0011] These and other embodiments will become apparent to those skilled in the art from the following detailed description of certain embodiments with reference to the accompanying drawings; the invention is not limited to any particular embodiment disclosed. Attached Figure Description

[0012] Exemplary embodiments of this disclosure can be more fully understood when considered in conjunction with the following illustrative drawings, and by referring to the detailed description and claims.

[0013] Figure 1 A method for forming a structure including a silicon nitride layer according to at least one embodiment of the present disclosure is shown.

[0014] Figure 2 Density and stress data of silicon nitride films formed according to at least one embodiment of the present disclosure are shown.

[0015] Figure 3 Density and hydrogen content data of silicon nitride films formed according to at least one embodiment of the present disclosure are shown.

[0016] Figure 4 Additional density and hydrogen content data for silicon nitride films formed according to at least one embodiment of the present disclosure are shown.

[0017] Figure 5 A schematic diagram of a reactor system according to an example of this disclosure is shown.

[0018] Figure 6 A schematic diagram of a reactor system with multiple modules according to an example of this disclosure is shown.

[0019] Figures 7 to 9The timing is shown to be suitable for use with the methods described in the examples according to this disclosure.

[0020] Figure 10 The relationship between surface roughness and deposition rate of SiN film according to an example of this disclosure is shown.

[0021] Figure 11 The effects of cyclic deposition and continuous wave (CW) plasma treatment on the roughness of silicon nitride films, according to an additional example, are shown.

[0022] It should be understood that the elements in the accompanying drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements to aid in understanding the embodiments shown in this disclosure. Detailed Implementation

[0023] Although certain embodiments and examples are disclosed below, those skilled in the art will understand that the invention extends beyond the specific embodiments and / or uses disclosed herein, as well as their obvious modifications and equivalents. Therefore, it is intended that the scope of the disclosed invention should not be limited to the specific embodiments described below.

[0024] This disclosure generally relates to methods for forming structures including silicon nitride (SiN) layers. As described in more detail below, the methods described herein can be used to form silicon nitride layers having desired properties (e.g., relatively high density, relatively high resistance to wet etch, relatively low surface roughness) and / or having desired compositions (e.g., desired (e.g., low hydrogen) concentrations).

[0025] The exemplary methods described herein can be used to form structures suitable for a variety of applications, such as electronic devices. For example, the method can be used to form structures suitable for etch stop layers, spacer formation, etc.

[0026] As used herein, the term substrate can refer to any one or more underlying materials that can be used to form or on which devices, circuits, or films are formed. A substrate may comprise a bulk material, such as silicon (e.g., single-crystal silicon), other group IV materials (e.g., germanium), or compound semiconductor materials (e.g., group III-V or group II-VI semiconductors), and may comprise one or more layers overlying or underlying the bulk material. Furthermore, a substrate may include various features such as gaps (e.g., recesses or vias), lines, or protrusions, such as lines having gaps formed therebetween, formed on or within at least a portion of the layers or bulk material of the substrate.

[0027] In some embodiments, a membrane refers to a layer extending in a direction perpendicular to the thickness direction. In some embodiments, a layer refers to a material of a certain thickness formed on a surface, and may be synonymous with a membrane or non-membrane structure. A membrane or layer may consist of discrete single membranes or layers or multiple membranes or layers having certain properties, and the boundaries between adjacent membranes or layers may or may not be clear, and may be established based on or not based on the physical, chemical and / or any other properties, formation process or sequence and / or function or purpose of adjacent membranes or layers.

[0028] In this disclosure, "continuous" or "serial" can refer to a step that does not break the vacuum, is uninterrupted in timeline, involves no material intervention, does not change processing conditions, follows immediately after, is the next step, or, in some embodiments and depending on the circumstances, is a discrete physical or chemical structure that, apart from the two structures, has no intervention between them.

[0029] As used herein, a silicon nitride layer or a layer comprising SiN comprises a material having silicon and nitrogen. In some embodiments, the SiN layer may contain one or more elements other than Si and N, such as H. In some embodiments, the SiN layer contains less than 8, 7, or 6 atomic percent hydrogen or other impurities.

[0030] In this disclosure, any two numbers of a variable may constitute a feasible range of the variable, and any range indicated may include or exclude endpoints. Furthermore, any value of the indicated variable (whether or not it is indicated by an approximation) may refer to an exact value or an approximate value and include equivalents, and in some embodiments may refer to the average, median, representative value, multi-value, etc. Additionally, in this disclosure, the terms include, comprise, constitute, and have in some embodiments may independently mean generally or broadly include, comprise, substantially constitute, or consist of. The meaning of any definition in this disclosure does not necessarily exclude the common and customary meaning in some embodiments.

[0031] Now turn to the attached image. Figure 1A method 100 for forming a structure including a silicon nitride layer according to an example of this disclosure is shown. Method 100 includes providing a substrate in a reaction chamber (step 102), providing a silicon precursor in a reaction chamber (step 104), providing a first nitrogen-containing reactant in a reaction chamber (step 106), optionally providing a second nitrogen-containing and / or hydrogen-containing reactant in a reaction chamber (step 108), providing a first plasma power (step 110), providing a second plasma power (step 112), and optionally processing the deposited material (step 118). Although shown individually, one or more (e.g., all) of steps 104-112 may overlap in time. For example, steps 104-112 may overlap in time to perform a plasma-enhanced chemical vapor deposition (PECVD) process, as shown in step 114. In some cases, one or more steps 104-118 may be repeated, as shown in loop 116.

[0032] The substrate provided during step 102 can be provided in any suitable reaction chamber of any suitable reactor. According to examples of this disclosure, the reaction chamber can be part of a chemical vapor deposition (CVD) reactor (such as a PECVD reactor). The reactor can be a single-substrate reactor or a batch reactor. A reactor including a reaction chamber can be equipped with a heater to activate the reaction by raising the temperature of one or more of the substrate and / or reactants and / or precursors. As a specific example, the reaction chamber can be or include a capacitively coupled plasma reactor. Exemplary reactors and reactor systems suitable for method 100 are described in more detail below.

[0033] After step 102 and during or before steps 104-108, the substrate may be brought to the desired temperature and pressure for forming the silicon nitride layer. For example, the temperature within the reaction chamber (e.g., the temperature of the substrate or substrate support) may be between about 100°C and about 600°C, or between about 400°C and about 500°C. During one or more steps in steps 104-108, the pressure within the reaction chamber may be between about 100 Pa and about 3000 Pa, or between about 300 Pa and about 1000 Pa, or between about 300 Pa and about 500 Pa.

[0034] During step 104, a silicon precursor is provided in the reaction chamber. The silicon precursor may be, or includes, for example, a silane. An exemplary silane may be made of formula Si n H 2n+2 This indicates that n is in the range of 1 to 4.

[0035] In some cases, a carrier gas is used to supply the silicon precursor to the reaction chamber. Exemplary suitable carrier gases include one or more of nitrogen, argon, helium, or any mixture thereof. The flow rate of the carrier gas used to supply the silicon precursor to the reaction chamber can be between about 100 and about 5000 sccm, or between about 2000 and about 4000 sccm. In some cases, the silicon precursor is supplied to the reaction chamber without the aid of a carrier gas. In either case, the flow rate of the silicon precursor (excluding the carrier gas) can be between about 5 sccm and about 20 sccm, or between about 10 sccm and about 50 sccm.

[0036] During step 106, a first nitrogen-containing reactant is provided in the reaction chamber. As described above, step 106 may overlap with step 104.

[0037] According to various examples, the first nitrogen-containing reactant does not include oxygen. According to a particular example, the first nitrogen-containing reactant includes nitrogen and hydrogen. Exemplary first nitrogen-containing reactants suitable for step 106 include one or more of nitrogen (N2), ammonia (NH3), hydrazine (N2H4), or triazine (N3H5). According to a more particular example, the nitrogen-containing reactant comprises or is substantially composed of one or more of N2, NH3, NH4, N2H2, N2H4, or mixtures thereof. According to examples of this disclosure, the flow rate of the first nitrogen-containing reactant to the reaction chamber is higher than the flow rate of the silicon precursor to the reaction chamber. For example, the ratio of the flow rate of the first nitrogen-containing reactant to the flow rate of the silicon precursor may be greater than 25, greater than 50, or between about 1500 and about 2000. In some cases, the ratio of atomic nitrogen in all nitrogen-containing reactants in the first nitrogen-containing reactant flow rate to atomic silicon in the silicon precursor flow rate may be greater than 25, greater than 50, or between about 1500 and about 2000. The flow rate of the first nitrogen-containing reactant can be between about 1 and 20 slm, or between about 2 and 10 slm, or between about 6 and 10 slm.

[0038] During step 108, a second nitrogen-containing reactant and / or a hydrogen-containing reactant are supplied to the reaction chamber. If both a second nitrogen-containing reactant and a hydrogen-containing reactant are supplied, these reactants may be supplied together or separately. In some cases, the second nitrogen-containing reactant may include hydrogen and / or the hydrogen-containing reactant may include nitrogen.

[0039] In some cases, the first nitrogen-containing reactant contains N2, and the second nitrogen-containing reactant is or includes one or more of ammonia (NH3), hydrazine (N2H4), or triazine (N3H5).

[0040] The hydrogen-containing reactant can be or includes H2. The flow rate of the hydrogen-containing reactant can be greater than the flow rate of the silicon precursor. For example, the ratio of the flow rate of the hydrogen-containing reactant to the flow rate of the silicon precursor can be greater than 5 or between about 80 and about 800. In some cases, the flow rate of the hydrogen-containing reactant to the reaction chamber is greater than 100 sccm, greater than 250 sccm, greater than 500 sccm and / or less than 5 slm, 4 slm, or 3 slm.

[0041] As a specific example, method 100 may include providing a silicon precursor to a reaction chamber, providing a first nitrogen-containing reactant (e.g., N2), and providing a hydrogen-containing reactant. In another example, method 100 may include providing a silicon precursor to a reaction chamber, providing a first nitrogen-containing reactant (e.g., N2), and providing a second nitrogen-containing reactant (e.g., NH3). In yet another example, method 100 may include providing a first nitrogen-containing reactant (e.g., N2), providing a second nitrogen-containing reactant (e.g., NH3, N2H4, and / or N3H5), and providing a hydrogen-containing reactant (e.g., H2) to a reaction chamber.

[0042] During step 110, a first plasma power is provided to the electrodes within the reaction chamber while one or more of the silicon precursor and the first nitrogen-containing reactant are being provided. As described below, according to examples of this disclosure, the electrodes are located within or at least a portion thereof within a base within the reaction chamber. The base may include a body comprising one or more of aluminum nitride or aluminum. In addition to the electrodes, one or more heating elements may be on or embedded in the base body.

[0043] For example, for a substrate with a diameter of 300 mm, the power of the first plasma can be between about 10 W and about 2000 W, or between about 50 W and about 500 W. The frequency of the first plasma power can be between about 50 MHz and about 200 MHz, or between about 50 MHz and 100 MHz. The duration of step 110 can be between about 5 seconds and about 3600 seconds. Power can be continuously provided during step 110. Alternatively, the power of the first plasma power can be pulsed on and off, or from high to low. The duty cycle of the pulsed first plasma power can be between about 1% and about 90%, or between about 1% and about 20%. When pulsed, the first plasma power can have a pulse frequency of about 50 Hz to about 100 Hz. The first plasma power can be provided as a pulsed wave. The first plasma power can be provided to the electrodes from the lower region of the reactor via conductive rods.

[0044] During step 112, while providing one or more of the silicon precursor and the first nitrogen-containing reactant, a second plasma power is supplied to electrodes (e.g., via conductive rods) within the reaction chamber. According to the examples disclosed herein, the frequency of the first plasma power is greater than the frequency of the second plasma power. According to another example, the power of the first plasma power is greater than the power of the second plasma power. For example, the power of the first plasma power is at least 2, 5, or at least 10 times greater than the power of the second plasma power. The power of the second plasma power may, for example, be between greater than 0 W and 1000 W, or between about 10 W and about 100 W. The frequency of the second plasma power (e.g., a wave) may be between about 100 kHz and about 2 MHz, or between about 400 kHz and about 500 kHz.

[0045] The second plasma power can be a continuous wave, or it can be pulsed on and off (or high and low) at a pulse frequency during step 112. The pulse frequency can be between about 50 Hz and about 5 kHz, or between about 50 Hz and about 500 Hz. The duty cycle can be between about 1 and about 50%, or between about 1 and about 20%. The duty cycle can be defined as the percentage of plasma power on time / (on time + off time); in the preceding equation, on and off can be replaced by high and low. The second plasma power can be provided as a pulsed wave.

[0046] According to an example of the invention, the pulses of the first plasma power and the second plasma power can be synchronized. According to other examples, the pulses of the first plasma power and the second plasma power are asynchronous or out of phase—for example, differing by about 180 degrees.

[0047] During steps 110 and / or 112, a plasma is formed in the reaction chamber, and one or more of a silicon precursor and a first nitrogen-containing reactant are provided by supplying plasma power to the electrodes within the reaction chamber. The use of high-frequency / first plasma power and low-frequency / second plasma power (e.g., pulsed low-frequency power) allows for the time-efficient formation of SiN films with desired properties (e.g., stress and composition). Furthermore, the use of pulsed plasma during deposition can provide deposited materials with relatively low surface roughness.

[0048] Figure 2The stress-density diagrams of PECVD SiN by conventional CCP and according to method 100 (HD-CCP) are shown. Conventional CCP uses an RF frequency of 13.56 MHz. Due to plasma sheath oscillations, the 13.56 MHz plasma exhibits high ion energy; ions can follow this oscillation. This ion bombardment results in high film stress at high film densities. On the other hand, HD-CCP can deposit high-density SiN films with relatively low stress. The sheath oscillation at an RF (HF, first plasma power) frequency of 60 MHz is too high for ions to follow. Furthermore, the high-density plasma can effectively dissociate the precursor gas and enhance the crosslinking reaction at the growth surface. Therefore, HD-CCP can deposit high-density SiN films with lower compressive stress.

[0049] Ions can be used to increase film density at lower deposition temperatures. To take advantage of ion bombardment, a low-frequency pulse (LF, second plasma power) is applied to the HD-CCP. The advantage of the pulsed LF power is that it allows for independent control of ion bombardment energy and flux. The duty cycle of the second plasma power pulse controls the ion flux, while the input power controls the ion bombardment energy. This independent ion bombardment control enables an increase in film density while maintaining... Figure 2 The same stress level (HD-CCP + pulsed LF power) is shown. High ion bombardment energy facilitates crosslinking reactions at the growth surface, and the relaxation time of the LF power off duration contributes to stress reduction.

[0050] Figure 3 The film density and hydrogen content are shown in relation to the effective LF power (W) of continuous wave (CW) and pulsed wave second plasma power. As mentioned above, SiN deposited using pulsed LF power exhibits a higher film density than SiN deposited with the same effective power using CW LF power. Furthermore, pulsed LF power has a significant benefit on the hydrogen content in the film. The hydrogen content can be measured by hydrogen forward scattering spectroscopy (HFS). In the case of CW power, the hydrogen content increases with increasing effective LF power, while by applying pulsed LF power, the hydrogen content decreases. The increase in hydrogen content is the same as with CW LF power when the effective LF power of pulsed LF increases. Precise control of ion bombardment enables the realization of high-density SiN films with moderate stress and low hydrogen content.

[0051] Figure 4The dependence of NH3 flow rate (as the second nitrogen-containing reactant) on membrane density and hydrogen content is shown. The gas mixture was SiH4 40 sccm, N2 (the first nitrogen-containing reactant) 8500 sccm, H2 2500 sccm, and NH3. As the NH3 flow rate decreased, the membrane density increased, and the hydrogen concentration decreased. When the N2 and H2 flow rates were sufficiently high, nitrogen and hydrogen radicals were generated from N2 and H2. NH3 was not required to generate nitrogen radicals to enhance SiN bond formation. NH3 readily generates NH termination in the membrane and increases the hydrogen content of the SiN membrane.

[0052] Table 1 shows a comparison of membrane properties between several CCP processes. SiN films obtained by HD-CCP, pulsed LRF, and NH3-free deposition showed a density of 2.86 g / cc and an H content of 7.2%. Further results were also obtained with hydrogen concentrations of 6 atomic% or lower.

[0053] Table 1

[0054]

[0055] return Figure 1 As described above, method 100 may include a processing step 118. Processing step 118 may be performed after a predetermined deposition time in chemical vapor deposition (PECVD) process 114 or steps 104-112. For example, the deposition time of process 114 may be selected such that SiN greater than 0 and less than 10 nm is deposited before processing step 118.

[0056] During step 118, a process gas and process plasma power may be supplied to the reaction chamber (e.g., the same reaction chamber used for process 114). The process gas may include, for example, N2, NH3, N2H4, N3H5, Ar, He, or Xe.

[0057] The processing plasma power may include a first processing plasma power and a second processing plasma power. The first processing plasma power may be between about 10 W and about 2000 W, or between about 50 W and about 500 W—for example, for a substrate with a diameter of 300 mm. The frequency of the first processing plasma power may be between about 50 MHz and about 200 MHz, or between about 50 MHz and 100 MHz. The first processing plasma power may be provided as a pulsed wave. The first processing plasma power may be pulsed on and off, or pulsed from high to low. The duty cycle of the first processing plasma power may be between about 1% and about 90%, or between about 1% and 20%. The first processing plasma power may have a pulse frequency of about 50 Hz to about 100 Hz. The first processing plasma power may be supplied to electrodes from the lower region of the reactor via conductive rods.

[0058] The second processed plasma power can be provided as a pulsed wave. During step 118, the second processed plasma power can be pulsed on and off (or between high and low) at a pulsed frequency. The pulsed frequency of the second processed plasma power can be between about 50 Hz and about 5 kHz, or between about 50 Hz and about 500 Hz. The duty cycle of the second processed plasma power can be between about 1% and about 50%, or between about 1% and about 20%.

[0059] According to examples of this disclosure, the pulses of the first processed plasma power and the second processed plasma power can be synchronized. According to other examples, the pulses of the first processed plasma power and the second processed plasma power are out of phase or out of phase—for example, about 180 degrees out of phase.

[0060] The duration of step 118 can be between approximately 5 seconds and approximately 3600 seconds. The duration of step 118 can be adjusted to have the desired effect on surface roughness and stress.

[0061] like Figure 1 As shown, steps 104-112 and 118 (loop 116) can be repeated, for example, until the desired thickness is obtained or the desired number of loops are performed.

[0062] Figures 7 to 9 Exemplary timings 700, 800, and 900 of method 100 are shown. Timings 700, 800, and 900 are intended to be illustrative and not limiting.

[0063] Time sequence 700 illustrates the plasma-enhanced chemical vapor deposition process. As shown, during time period 720, a deposition gas can flow into the reaction chamber. The deposition gas may include a silicon precursor, a first nitrogen-containing reactant, and optionally a second nitrogen-containing reactant and / or a hydrogen-containing reactant, such as those mentioned above in conjunction with steps 104-108. During time period 704, pulsed first and / or second plasma power is provided to form (e.g., continuous) plasma within the reaction chamber. The first and / or second power can be as described above in conjunction with steps 110 and 112. Figure 7 In the example shown, no processing was performed.

[0064] Figure 8Another timing sequence 800 applicable to method 100 is shown. Timing sequence 800 is similar to timing sequence 700, except that timing sequence 800 includes a deposition process 802 that may be the same as or similar to deposition process 114, and a processing step 804 that may be the same as processing step 118. In the example shown, timing sequence 800 includes providing a deposition gas (e.g., a silicon precursor, a first nitrogen-containing reactant, and optionally a second nitrogen-containing reactant and / or a hydrogen-containing reactant) during time period 806, and providing pulsed first and / or second plasma power during time period 808 to form (e.g., continuous) plasma in the reaction chamber. During deposition process 802, the process gas may not flow to the reaction chamber. During processing step 804, the process gas may flow to the reaction chamber or another reaction chamber during time period 810, and during time period 812, pulsed process plasma power may be applied to form (e.g., continuous) plasma in the reaction chamber. As shown in loop 814, timing sequence 800 may be repeated once or multiple times.

[0065] Figure 9 Another process timing 900 applicable to method 100 is shown. Timing 900 includes a deposition process 902, which may be the same as or similar to deposition process 114, and a processing step 904, which may be the same as processing step 118. Timing 900 may be the same as timing 800, except that deposition process 902 includes providing deposition gas (which may be as described above) during time period 906 and providing continuous plasma power (e.g., the first and / or second plasma power as described above) during time period 908. Processing step 904 includes providing processing gas for a period of time 910 and applying pulsed processing plasma power for a period of time 912. Processing step 904 may be the same as processing steps 804 or 118.

[0066] Figure 10 The surface roughness of SiN films deposited using pulsed plasma deposition power (e.g., during steps 110 and / or 112) and constant power during steps 110 and 112 is shown as a function of deposition rate. As shown, surface roughness decreases as the deposition rate decreases.

[0067] Figure 11The effects of cyclic deposition and continuous wave (CW) plasma treatment on roughness are illustrated. Cyclic deposition processes with a CW treatment step increase the deposition rate (thickness divided by the total deposition time of the cycle), which increases roughness. It is assumed that CW plasma treatment produces byproduct deposition (so-called redeposition) during the process. Although plasma treatment can generally smooth surfaces through densification and surface etching, redeposition results in a relatively rough surface. Pulsed plasma power can reduce redeposition of byproducts during treatment. Pulsed plasma can have a plasma or weak plasma off-time, which helps to remove byproducts from the treated area and suppress redeposition.

[0068] Figure 5 The present invention illustrates a reactor system 500 according to an exemplary embodiment of the present disclosure. The reactor system 500 may be used to perform one or more steps or sub-steps as described herein and / or to form one or more structures or portions thereof as described herein.

[0069] Reactor system 500 includes a pair of parallel, facing conductive plate electrodes 514, 518 within the interior 501 (reaction zone) of reaction chamber 502. Plasma can be excited within reaction chamber 502 by applying plasma power, for example from plasma power source 508, to one electrode (e.g., electrode 514) and electrically grounding the other electrode (e.g., electrode 518). Power source 508 can be coupled to electrode 514 via transmission line 529, (e.g., RF) filter 531, and conductive rod 534. Power source 508 can provide first and second processing powers with frequencies and waveforms as described herein. Feeding power to the lower electrode / base 514 prevents or mitigates parasitic discharges at the top electrode 518. The first plasma power frequency, as described herein, is sensitive to parasitic capacitance and therefore prone to discharge. Furthermore, cleaning can be achieved using a relatively large upper volume 538 spray head electrode 518 to deliver clean free radical material formed from clean gas from clean gas source 540 and RPU 536 into chamber 501. However, volume 538 tends to have anomalous discharges with VHF. By bottom-feeding at least a first plasma power, the system becomes simple and enables high-density plasma generation only in the processing space. The bottom-feed configuration also allows for two or four reaction chamber configurations within a single system or module.

[0070] Temperature regulator 503 may be disposed in lower platform 514 (lower electrode or base), and the temperature of substrate 522 placed thereon may be maintained at a desired temperature, such as the temperature described above. Base 514 may include body 552, which is formed of, for example, ceramic (e.g., aluminum nitride). In some cases, base 514 may include conductive members 550, such as wires, rods, or plates embedded in or on body 552, to distribute power from power source 508.

[0071] Electrode 518 can be used as a gas distribution device, such as a spray plate or spray head. One or more gas lines (e.g., reactant gas line 504 and precursor gas line 506 connected to the reactant source and precursor source, respectively) can be used to introduce precursor gas, reactant gas, and carrier gas or inert gas (if any) into reaction chamber 502. For example, line 504 and / or precursor can be used to introduce inert gas and reactants (e.g., as described above) into reaction chamber 502, and line 506 can be used to introduce carrier gas (e.g., inert gas as described above) into reaction chamber 502. Although two inlet gas lines 504, 506 are shown, reactor system 500 may include any suitable number of gas lines. System 500 may further include a silicon precursor source 542 connected to the reaction chamber, which includes a first container and a silicon precursor; a first nitrogen source 544, which includes a second container and a first nitrogen-containing reactant; a second nitrogen source 546, which includes a third container and a second nitrogen-containing reactant; a hydrogen source 548, which includes a fourth container and a hydrogen-containing reactant; and a process gas source 554, which includes a fifth container and a process gas.

[0072] In reaction chamber 502, a circular pipe 520 with an exhaust line 521 can be formed within a metal pipe plate 530. Gas in the interior 501 of reaction chamber 502 can be discharged to exhaust source 510 through this circular pipe 520. Additionally, transfer chamber 523 can be provided with a sealing gas line 532 to introduce sealing gas into the interior 501 of reaction chamber 502 via the interior of transfer chamber 523 (transfer zone). A separation plate 525 (omitted in this figure, through which the substrate is transferred in and out of transfer chamber 523) can be provided for separating reaction zone 501 and transfer chamber 523. The transfer chamber 523 can also be provided with an exhaust line 527 connected to exhaust source 510.

[0073] Reactor system 500 may include one or more controllers 512, which are programmed or otherwise configured to cause one or more method steps as described herein to be performed. As will be understood by those skilled in the art, controller 512 is connected to various power sources, heating systems, pumps, robots, and gas flow controllers or valves of the reactor. For example, controller 512 may be configured to control the gas flow of precursors, reactants, and inert gases into at least one of one or more reaction chambers to form a layer on the surface of a substrate. Controller 512 may be further configured to provide power to, for example, form a plasma within reaction chamber 502, as described herein. Controller 512 may similarly be configured to perform additional or alternative steps as described herein. As a specific example, controller 512 may be configured to provide a first nitrogen-containing reactant and a silicon precursor at a volumetric flow rate ratio greater than 25:1, provide a first plasma power to electrodes within the reaction chamber while providing one or more of the silicon precursor and the first nitrogen-containing reactant, and provide a second plasma power to electrodes within the reaction chamber, wherein the frequency of the first plasma power is between about 50 MHz and about 200 MHz, and wherein the frequency of the second plasma power is between about 50 Hz and about 5 kHz. Alternatively, controller 512 may be configured to provide processing plasma power to reaction chamber 502.

[0074] Controller 512 may include electronic circuitry and software to selectively operate valves, manifolds, heaters, pumps, and other components included in system 500. Such circuitry and components operate to introduce precursors, reactants, and purge gases from appropriate sources. Controller 512 may control the timing of gas pulse sequences, the temperature of the substrate and / or reaction chamber, the pressure within the reaction chamber, and various other operations to provide appropriate operation of system 500.

[0075] Controller 512 may include control software to electrically or pneumatically control valves to control the inflow and outflow of precursors, reactants, and / or purge gases from reaction chamber 502. Controller 512 may include modules, such as software or hardware components, like FPGAs or ASICs, that perform certain tasks. Modules may be advantageously configured to reside on addressable storage media of the control system and configured to perform one or more processes.

[0076] In some embodiments, a dual-chamber reactor (for processing two portions or compartments of a substrate disposed close to each other) may be used, wherein reactant gases and rare gases may be supplied via a common line, while precursor gases may be supplied via a non-common line.

[0077] During operation of system 500, a substrate, such as a semiconductor wafer, is transferred from, for example, substrate transport region 523 to reaction region 501. Once the substrate is transferred to reaction region 501, one or more gases (e.g., precursors, reactants, carrier gases, and / or purge gases) are introduced into reaction chamber 502.

[0078] Figure 6 A reactor system 600 comprising multiple modules 602-608 is illustrated. Each module may include one or more (e.g., 1, 2, or 4) reaction chambers, such as reaction chamber 502 described above. Modules 602-608 may be disposed around and / or coupled to transfer chamber 610, and include transfer tools 612 for transferring substrates between modules 602-608 and loading locking chamber 614, and between modules 602-608 (e.g., through transfer chamber 610). For example, substrates may be disposed in different chambers or modules for different steps of the method described herein. Modules may include one or more controllers as described herein.

[0079] The exemplary embodiments described above do not limit the scope of the invention, as these embodiments are merely examples of embodiments of the invention, the scope of which is defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to fall within the scope of the invention. In fact, various modifications to this disclosure, such as alternative useful combinations of the described elements, in addition to those shown and described herein, will become apparent to those skilled in the art from the description. These modifications and embodiments are also intended to fall within the scope of the appended claims.

Claims

1. A method for forming a structure including a silicon nitride layer, the method comprising: A substrate is provided within the reaction chamber of the reactor; Silicon precursors are provided within the reaction chamber; The first nitrogen-containing reactant is provided in the reaction chamber; While providing one or more of a silicon precursor and a first nitrogen-containing reactant, a first plasma power is supplied to the electrodes in the reaction chamber; as well as While providing one or more of a silicon precursor and a first nitrogen-containing reactant, a second plasma power is supplied to the electrodes within the reaction chamber. The frequency of the first plasma power is greater than the frequency of the second plasma power.

2. The method according to claim 1, wherein, The silicon precursor includes silane.

3. The method according to claim 1 further includes a processing step.

4. The method according to claim 3, wherein, The processing steps include providing pulsed processing plasma power to the electrodes.

5. The method according to claim 1, wherein, The method further includes the step of providing a second nitrogen-containing reactant.

6. The method according to claim 1, wherein, The ratio of the flow rate of the first nitrogen-containing reactant to the flow rate of the silicon precursor is greater than 25, greater than 50, or between about 1500 and about 2000.

7. The method according to claim 1, wherein, The method also includes the step of providing hydrogen-containing reactants to the reaction chamber.

8. The method according to claim 7, wherein, The ratio of the flow rate of the hydrogen-containing reactant to the flow rate of the silicon precursor is greater than 5 or between about 80 and about 800.

9. The method according to claim 1, wherein, The electrode is located within a base inside the reaction chamber.

10. The method according to claim 9, wherein, The base includes a body that contains one or more of aluminum nitride or aluminum.

11. The method according to claim 9, wherein, The first plasma power and the second plasma power are supplied from the lower region of the reactor via conductive rods.

12. The method according to claim 1, wherein, The power of the first plasma is between 10W and 2000W.

13. The method according to claim 1, wherein, The power of the second plasma is between 0W and 1000W.

14. The method according to claim 1, wherein, The power of the first plasma power is greater than that of the second plasma power.

15. The method according to claim 1, wherein, The power of the first plasma power is at least 2 times or at least 10 times greater than the power of the second plasma power.

16. The method according to claim 1, wherein, The power of the second plasma is pulsed at a pulse frequency.

17. The method according to claim 16, wherein, The pulse frequency is between approximately 50 Hz and approximately 5 kHz.

18. A method for forming a structure including a silicon nitride layer, the method comprising: A substrate is provided within the reaction chamber of the reactor; Silicon precursors are provided within the reaction chamber; The first nitrogen-containing reactant is provided in the reaction chamber; as well as While providing one or more of a silicon precursor and a first nitrogen-containing reactant, a first plasma power is supplied to the electrodes within the reaction chamber. The frequency of the first plasma power is between approximately 50 MHz and 200 MHz, and The ratio of the flow rate of the first nitrogen-containing reactant to the flow rate of the silicon precursor is greater than 25, greater than 50, or between about 1500 and about 2000.

19. The method of claim 18, further comprising: While providing one or more of the silicon precursor and the first nitrogen-containing reactant, a second plasma power is supplied to the electrodes within the reaction chamber. The frequency of the first plasma power is greater than the frequency of the second plasma power.

20. The method according to claim 18, wherein, The method also includes the step of providing hydrogen-containing reactants to the reaction chamber.

21. The method according to claim 20, wherein, The ratio of the flow rate of the hydrogen-containing reactant to the flow rate of the silicon precursor is greater than 5 or between about 80 and about 800.

22. The method of claim 18, further comprising a processing step.

23. A reactor system, comprising: Reaction chamber; A silicon precursor source, comprising a first container and a silicon precursor, is connected to a reaction chamber; The first nitrogen source includes a second container and a first nitrogen-containing reactant; The second nitrogen source includes a third container and a second nitrogen-containing reactant; A hydrogen source, comprising a fourth container and hydrogen-containing reactants; At least one plasma power source, and The controller is configured as follows: The first nitrogen-containing reactant and silicon precursor are provided at a volumetric flow ratio greater than 25:1; While providing one or more of a silicon precursor and a first nitrogen-containing reactant, a first plasma power is supplied to the electrodes in the reaction chamber; as well as A second plasma power is supplied to the electrodes inside the reaction chamber. The frequency of the first plasma power is between approximately 50 MHz and approximately 200 MHz, and The frequency of the second plasma power is between approximately 50 Hz and approximately 5 kHz.

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