Systems and methods for multi-step directed patterning

Abstract

The present disclosure relates to systems and methods for multi-step directed patterning. A semiconductor process system includes an ion source configured to bombard a photoresist structure on a wafer. The semiconductor process system reduces a width of the photoresist structure by bombarding the photoresist structure with ions in a plurality of different ion bombardment steps having different characteristics.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor processing. More specifically, this disclosure relates to patterning features on a semiconductor wafer. Background Technology

[0002] The need to increase the computing power of electronic devices, including smartphones, tablets, desktop computers, laptops, and many other types of electronic devices, has always existed. One way to increase the computing power of integrated circuits is to increase the number of transistors and other integrated circuit features that can be included in a given area of ​​a semiconductor substrate.

[0003] To further reduce the size of features in integrated circuits, various thin-film deposition, etching, and other processing techniques have been implemented. Many etching processes involve depositing a layer of photoresist and then exposing that photoresist to ultraviolet light through a photomask to pattern the photoresist. The mask contains the pattern to be formed in the photoresist. However, as the size of the desired features decreases, it may become difficult to pattern the photoresist in the desired manner. Summary of the Invention

[0004] According to one embodiment of this disclosure, a method for semiconductor processing is provided, comprising: depositing a photoresist on a substrate; forming a trench in the photoresist; and widening the trench by: bombarding a first side of the trench with ions from a first angle, and bombarding the first side of the trench with ions from a second angle different from the first angle.

[0005] According to another embodiment of this disclosure, a method for semiconductor processing is provided, comprising: depositing a photoresist on a substrate; forming a photoresist structure by patterning the photoresist; and reducing the width of the photoresist structure by bombarding a first side of the photoresist structure with ions having a first energy, and after bombarding the first side of the photoresist structure with ions having the first energy, bombarding the first side of the photoresist structure with ions having a second energy different from the first energy.

[0006] According to another embodiment of this disclosure, a system for semiconductor processing is provided, comprising: a semiconductor processing chamber; a wafer support configured to support a wafer in the semiconductor processing chamber; an ion source positioned to bombard the wafer with ions; and a control system coupled to the ion source, the control system comprising: at least one processor; and at least one memory coupled to the at least one processor, the at least one memory having instructions stored therein, the instructions, when executed by the one or more processors, causing the ion source to: bombard a side of a photoresist structure on the wafer from a first angle in a first ion bombardment step, bombard the side of the photoresist structure from the first angle in a second ion bombardment step, and bombard the side of the photoresist structure from a second angle different from the first angle in a third ion bombardment step. Attached Figure Description

[0007] Various aspects of this disclosure can be best understood from the following detailed description taken in conjunction with the accompanying drawings. Note that, in accordance with industry standard practice, the various features are not drawn to scale. In fact, for clarity of discussion, the dimensions of the various features may be arbitrarily enlarged or reduced.

[0008] Figure 1 This is a diagram of a semiconductor process system according to one embodiment.

[0009] Figures 2A-2J This is a cross-sectional view of a wafer according to one embodiment.

[0010] Figure 2K According to one embodiment Figure 2A A top view of the wafer.

[0011] Figure 2L According to one embodiment Figure 2H A top view of the wafer.

[0012] Figure 3 This is a graph showing the variation of photoresist width for various ion bombardment characteristics according to one embodiment.

[0013] Figures 4A-4D This is a top view of a wafer according to one embodiment.

[0014] Figures 5A-5D This is a top view of a wafer according to one embodiment.

[0015] Figure 6 This is a perspective view of a wafer according to one embodiment.

[0016] Figure 7 This is a block diagram of a control system according to one embodiment.

[0017] Figure 8 This is a flowchart of a method for processing a wafer according to one embodiment.

[0018] Figure 9 This is a flowchart of a method for processing a wafer according to one embodiment. Detailed Implementation

[0019] In the following description, numerous thicknesses and materials are described for various layers and structures within an integrated circuit die. Specific dimensions and materials are given by way of example for various embodiments. Based on this disclosure, those skilled in the art will recognize that other dimensions and materials may be used in many cases without departing from the scope of this disclosure.

[0020] The following disclosure provides numerous different embodiments or examples for implementing various features of the provided subject matter. Specific examples of components and arrangements are described below to simplify this disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the following description of forming a first feature on or over a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features such that the first and second features may not be in direct contact. Furthermore, reference numerals and / or letters may be repeated in various examples. Such repetition is for simplicity and clarity and does not, in itself, indicate a relationship between the various embodiments and / or configurations discussed.

[0021] Furthermore, this document may use spatially relevant terms (e.g., "below," "below," "lower than," "above," "upper," etc.) to readily describe the relationship of one element or feature shown in the figure relative to another element(s) or feature(s). In addition to the orientation shown in the figure, spatially relevant terms are also intended to cover different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relevant descriptors used herein may be interpreted accordingly.

[0022] In the following description, certain specific details are set forth to provide a thorough understanding of various embodiments of this disclosure. However, those skilled in the art will understand that this disclosure can be practiced without these specific details. In other instances, well-known structures associated with electronic components and manufacturing techniques have not been described in detail to avoid unnecessarily obscuring the description of embodiments of this disclosure.

[0023] Unless the context otherwise requires, throughout the specification and the following claims, the word “comprising” and its variations, such as “including” and “containing”, shall be interpreted in an open, inclusive sense, meaning “including” but not limited to.

[0024] The use of ordinal numbers such as first, second, and third does not necessarily imply a sense of sequential order, but may simply be a distinction between multiple instances of an action or structure.

[0025] Throughout this specification, references to "an embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Therefore, the appearance of the phrase "in some embodiments" or "in an embodiment" throughout this specification does not necessarily refer to the same embodiment. Furthermore, these particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0026] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include the plural forms unless the context clearly indicates otherwise. It should also be noted that the term “or” is generally used to include the meaning of “and / or” unless the context clearly indicates otherwise.

[0027] Embodiments of this disclosure reduce the size of the photoresist structure after initial patterning of the photoresist. The photoresist is initially deposited on a wafer and patterned by exposure through a mask. This initial patterning process forms trenches or holes in the photoresist. Remaining photoresist separates the trenches or holes. After initial patterning, the lateral dimension of the remaining photoresist structure may be larger than desired. Embodiments of this disclosure reduce the lateral dimension of the remaining photoresist by removing a portion of it using multiple steps of directed ion bombardment. The multiple steps of directed ion bombardment reduce the lateral dimension of the remaining photoresist structure and correspondingly increase the width of the trenches or holes. This is highly advantageous because the structures can be formed more tightly together.

[0028] Figure 1 This is a simplified illustration of a semiconductor process system 100 according to one embodiment. The semiconductor process system includes a processing chamber 102. A wafer support 104 is located in the processing chamber 102. The wafer support 104 supports a wafer 106 in the processing chamber 102. An ion source 108 is located in the processing chamber 102. As will be described in more detail below, the components of the semiconductor process system 100 cooperate to pattern a photoresist on the wafer 106 via multiple steps of ion bombardment.

[0029] Figure 1A single processing chamber 102 is shown. However, as will be explained in more detail below, some of the processes described below can be performed in different processing chambers.

[0030] Semiconductor process system 100 includes semiconductor process equipment 110. Semiconductor process equipment 110 assists in performing semiconductor processes. Semiconductor process equipment 110 may include equipment for assisting photolithography processes. For example, semiconductor process equipment 110 may include equipment for depositing a photoresist layer on wafer 106. Semiconductor process equipment 110 may include equipment for performing initial patterning of the photoresist. Therefore, semiconductor process equipment 110 may include a photomask, ultraviolet light generation equipment, and associated optical equipment for guiding ultraviolet light onto the photoresist layer.

[0031] Process equipment may include equipment for performing thin film deposition processes, etching processes, ion implantation processes, annealing processes, photolithography processes, and other types of processes. Some semiconductor process equipment 110 may be located partially inside and partially outside the processing chamber 102. Some semiconductor process equipment 110 may be located entirely outside the processing chamber 102.

[0032] Semiconductor process apparatus 110 may include means for managing fluid flow within a processing chamber 102. The apparatus may include components for introducing gas or fluid into the processing chamber 102, removing gas or fluid from the processing chamber, and monitoring and controlling the flow, presence, or composition of gas within the processing chamber 102. Semiconductor process apparatus 110 may include means for maintaining a selected pressure within the processing chamber 102.

[0033] Semiconductor process equipment 110 may include electrical components for generating electric fields, voltages, magnetic fields, electrical signals, or other types of electrical effects. Therefore, semiconductor process equipment 110 may include electrodes, wires, radio frequency power supplies, transmitters, receivers, or other types of electrical devices that can be used in semiconductor processes.

[0034] Semiconductor process equipment 110 is used to deposit a photoresist layer on wafer 106. After the photoresist layer has been deposited on wafer 106, semiconductor process equipment 110 performs initial patterning of the photoresist. Initial patterning forms trenches or holes in the photoresist according to the pattern of a photomask. Specifically, the photoresist is exposed through a mask, thereby altering the exposed photoresist structure. Unexposed portions of the photoresist do not undergo structural changes due to the presence of the mask. The initial patterning process includes removing either the photoresist portions altered by exposure or those not altered by exposure, depending on the type of photoresist used and the photolithography process. Removing the photoresist after exposure produces the initial pattern of trenches and holes in the photoresist.

[0035] Due to limitations in photolithography, the remaining photoresist structures defining trenches and holes may have one or more lateral dimensions that are wider than desired. As used herein, lateral dimensions correspond to mutually orthogonal X and Y dimensions and to the Z dimension corresponding to the vertical thickness of the photoresist. Therefore, due to limitations in photolithography, the lateral width of some remaining photoresist structures may be greater than expected.

[0036] After initial patterning, system 100 utilizes ion source 108 to reduce the lateral width of the remaining photoresist portion. Ion source 108 outputs an ion beam, directed at a selected angle relative to the vertical direction toward wafer 106. The ions bombard or collide with the photoresist. The impact of ions on the remaining photoresist structure removes a portion of the remaining photoresist structure. This reduces the lateral width of the remaining photoresist structure. This reduction in lateral photoresist size caused by directional ion bombardment can be termed directional drive.

[0037] Ion source 108 bombards the photoresist structure with ions in multiple steps. In the first ion bombardment step, the ions travel at an angle relative to the vertical direction, with energy and dose levels. In the subsequent second ion bombardment step, one or more aspects of the ion beam differ from those of the first ion bombardment step. Therefore, in the second ion bombardment step, one or more of the ion beam's travel angle, energy, or dose level differs from those of the first ion bombardment step. Compared to performing only a single ion bombardment step or the second ion bombardment step being identical to the first ion bombardment step, two ion bombardment steps with different characteristics allow for a more effective reduction in the width of the remaining photoresist feature.

[0038] In one embodiment, in the first ion bombardment step, ions are emitted toward wafer 106 at a first angle relative to the vertical direction. In the subsequent second ion bombardment step, ions are emitted toward wafer 106 at a second angle different from the first angle. This combination of different ion bombardment angles reduces the effect of shading and allows for effective removal of photoresist. Shading reduces the effectiveness of the ion bombardment process. (Reference) Figures 2A-2L Further details about shadows are explained.

[0039] In one embodiment, during the first ion bombardment step, ions are emitted toward wafer 106 with a first energy. In the subsequent second ion bombardment step, ions are emitted toward wafer 106 with a second energy different from the first energy. This combination of different ion bombardment energies reduces hardening and allows for efficient removal of photoresist. The energy of an ion corresponds to its kinetic energy. For two ions of the same mass, the ion with higher energy will have a higher velocity than the ion with lower energy.

[0040] In one embodiment, in a first ion bombardment step, a first dose of ions is output from ion source 108 to wafer 106. In a subsequent second ion bombardment step, a second dose of ions, different from the first dose, is output from ion source 108 to wafer 106. As used herein, a dose corresponds to the number of ions that bombard wafer 106 in a given ion bombardment step. A higher ion bombardment dose corresponds to a greater number of ions bombarding wafer 106. If the number of ions per second is constant for both ion bombardment steps, then a higher dose can correspond to a longer bombardment time of wafer 106.

[0041] In practice, two ion bombardment steps will be performed on each side of the photoresist structure. If the photoresist structure is considered to be a vertical wall with two vertical sides and a top surface, then in one embodiment, the two ion bombardment steps will be performed first on one vertical side and then on the other vertical side. Therefore, after two ion bombardment steps are performed on the first vertical side, two ion bombardment steps will then be performed on the second vertical side. To achieve this, after the first two ion bombardment steps, wafer 106 is rotated 180° in the XY plane. The latter two ion bombardment steps are then performed after the rotation.

[0042] In one embodiment, a first ion bombardment step is first performed on a first vertical side of the photoresist structure. Then, the wafer is rotated 180° in the XY plane, and the first ion bombardment step is performed on a second vertical side of the photoresist structure. Then, a second ion bombardment step is performed on the second vertical side of the photoresist structure. Then, the wafer is rotated 180° in the XY plane, and the second ion bombardment step is performed on the first vertical side of the photoresist structure.

[0043] System 100 includes a control system 112. Control system 112 is coupled to ion source 108. Control system 112 sends commands to ion source 108 to control parameters of ion bombardment. Therefore, control system 112 can control ion source 108 to output ions at a selected angle, selected energy, and selected dose. Control system 112 controls ion source 108 to change one or more of these parameters from a first ion bombardment step to a second ion bombardment step.

[0044] The control system 112 may also be coupled to the process equipment 110. The control system 112 can control the functions of the process equipment 110. The control system 112 may also be coupled to the support 104. The control system 112 can control the rotation of the support 104. Specifically, after the first and second ion bombardment steps have been performed on the first side of the photoresist feature, the control system 112 can cause the support 104 to rotate the wafer 106 by 180°. The control system 112 can then cause the ion source 108 to perform the first and second ion bombardment steps on the second side of the photoresist feature. Alternatively, the system 100 may include a robotic arm or other mechanism for rotating the wafer 106 between sets of ion bombardment steps. The control system 112 can control the robotic arm or other mechanism.

[0045] Figure 2A This is a cross-sectional view of a wafer 106 in an intermediate stage of processing according to one embodiment. The wafer includes a substrate 122 and a photoresist structure 120 on the substrate 122. The substrate 122 may include a dielectric layer, a conductive layer, a semiconductor layer, or other types of material. In one example, the substrate 122 is an interlayer dielectric layer, such as silicon oxide, silicon nitride, or other suitable dielectric material.

[0046] The photoresist structure 120 is a residue of a photoresist layer that has been patterned by an initial patterning process. The initial patterning process may include standard photolithography patterning, such as exposing a mask to ultraviolet light and removing the exposed or unexposed photoresist.

[0047] Each photoresist structure 120 includes a first side surface 124, a second side surface 126, and a top surface. The photoresist structure can be considered as a photoresist wall. Each photoresist structure has a width W1. An initial patterning process defines trenches 128 between adjacent photoresist structures 120. Each trench 128 has a width W2 between adjacent photoresist structures. Figure 2A The X dimension is shown to be the lateral dimension between adjacent photoresist structures 120. Figure 2A The Z dimension is shown to be the vertical dimension. Figure 2K and Figure 2L The top view shows that the Y dimension is a lateral dimension perpendicular to both the X and Z dimensions. Figure 2A In the view, the Y dimension corresponds to the dimension of the sheet.

[0048] In some cases, it is desirable to reduce the width W1 of the photoresist structure 120. This can correspond to widening the trench 128. As previously mentioned, standard photolithography processes may not be able to produce a photoresist structure 120 with the desired lateral dimensions.

[0049] One solution to reduce the width of the photoresist structures 120 is to bombard them with ions. To reduce the lateral dimensions, walls 124 and 126 can be bombarded with ions. To bombard walls 124 and 126 with ions, the ions will travel at an angle relative to the vertical direction. However, there are some difficulties in bombarding the sidewalls 124 and 126 at a certain angle. If the angle relative to the vertical direction is too large, adjacent photoresist structures 120 will prevent ions from striking the lower part of the sidewalls 124 or 126 of the photoresist structure 120. Therefore, material will only be removed from the upper part of the walls 124 or 126. This problem is called shading. If the ion bombardment angle is reduced so that ions can strike the entire wall 124 or 126, less photoresist material is removed because fewer ions strike the wall per surface area. Furthermore, the ion beam can produce a hardening effect on the sides 124 and 126 of the photoresist structure 120. The hardening of the photoresist results in less material being removed.

[0050] Embodiments of this disclosure overcome or reduce the effects of hardening or shading by performing ion bombardment on each side 124 and 126 in two separate ion bombardment steps. One or more characteristics of the ion bombardment are varied between the first and second steps. Some of the characteristics that can be varied include the bombardment angle, ion energy, and dose level. Figures 2B-2H The change in the bombardment angle between the first and second bombardment steps is shown. However, as will be explained in more detail below, aside from the bombardment angle, other characteristics may be changed between the first and second bombardment steps.

[0051] Figure 2B The first ion bombardment step of the first sidewall 124 of the photoresist structure 120 is shown. This can also be considered as bombardment of the first sidewall of the trench 128. Ions 129 are emitted from the ion source 108 (see...). Figure 1 Emission. Ion 129 travels at an angle θ1 relative to the vertical direction. From Figure 2B As can be seen, ions 129 impact the upper part of side 124 but not the lower part. This is due to the shading effect described earlier. Specifically, ions 129 that would impact the lower part of side 124 are prevented from doing so by the adjacent photoresist structure 120. The larger the angle θ1 relative to the vertical direction, the smaller the portion of side 124 impacted by ions 129 will be. However, it is advantageous to perform the first ion bombardment step by bombarding the upper part of side 124 at a first angle θ1. In one embodiment, ions 129 are argon ions. However, ions 129 may be other types of ions without departing from the scope of this disclosure.

[0052] In one embodiment, the first angle θ1 is between 55° and 65° relative to the vertical direction. If angle θ1 is above this range, insufficient upper portion of wall 124 may be bombarded by ions 129 for the first bombardment step. If angle θ1 is below this range, insufficient number of ions per unit area may bombard wall 124 for the first ion bombardment step. In one example, angle θ1 is 60°. Other angles of θ1 may be used without departing from the scope of this disclosure.

[0053] Figure 2C The wafer 106 is shown after the first ion bombardment step on the side surface 124 of the photoresist structure 120. It can be seen that the photoresist material has been removed from the upper part of the side surface 124 of the photoresist structure 120. The material has not been removed from the lower part of the side surface 124 of the photoresist structure 120.

[0054] Figure 2D A second ion bombardment step is shown for the first side 124 or the first side of the trench 128 of the photoresist structure 120. The ion source 108 outputs ions 129 at a second angle θ2 relative to the vertical direction. Angle θ2 differs from the first angle θ1. Angle θ2 is smaller than angle θ1 relative to the vertical direction. Angle θ2 is selected such that ions 129 bombard the entire side 124 of the photoresist structure 120. No shading effect occurs during the second ion bombardment step.

[0055] In one embodiment, the second angle θ2 is between 40° and 50° relative to the vertical direction. If the angle θ2 is above this range, shading may occur and the photoresist material may not be removed from the lower part of the side 124. If the angle θ2 is below this range, insufficient ions per unit area may impact the wall 124 for the second ion bombardment step. In one example, the angle θ2 is 45°. Other angles of θ2 may be used without departing from the scope of this disclosure.

[0056] Figure 2E Wafer 106 is shown after a second ion bombardment step on the side 124 of the photoresist structure 120. It can be seen that the photoresist material has been removed from both the lower and upper portions of the side 124 of the photoresist structure 120. Using a high incident angle in the first ion bombardment step results in a slope on the side 124 that is exactly above the lower portion of the side 124. This slope makes the second low incident angle ion bombardment step more effective because the ions strike the tilted portion at an angle closer to the normal. Therefore, the combination of the high incident angle first bombardment step and the low incident angle second bombardment step effectively removes material from the side 124 of the photoresist structure 120. The combination of the high incident angle first ion bombardment step and the low incident angle second bombardment step reduces the effect of shading and effectively removes the photoresist.

[0057] exist Figure 2F In this process, wafer 106 has been rotated 180° in the XY plane. As a result, the side 126 of the photoresist structure 120 is exposed to the ion source 108 (see...). Figure 1 ).exist Figure 2F In this process, a first ion bombardment step is performed on the side 126 of the photoresist structure 120. This corresponds to performing the first ion bombardment step on the second side of the trench 128. Ions 129 are output from the ion source 108 at a first angle θ1. In other words, Figure 2F The first ion bombardment step shown on side 126 is similar to Figure 2B The first ion bombardment step for side 124 is essentially the same. A potential difference means that a smaller portion of side 126 may be affected by shading due to material removal from the first side 124 as previously described. The first ion bombardment step for side 126 results in the removal of photoresist material from the upper part of side 126, such as... Figure 2G As shown.

[0058] exist Figure 2G In this process, a second ion bombardment step is performed on the side 126 of the photoresist structure 120. This corresponds to performing a second ion bombardment step on the second side of the trench 128. Ions 129 are output from the ion source 108 at a second angle θ2. In other words, Figure 2G The second ion bombardment step shown on side 126 is similar to Figure 2D The second ion bombardment step of side 124 is essentially the same. The second ion bombardment step of side 126 results in the removal of photoresist material from both the upper and lower parts of side 126.

[0059] Figure 2H A wafer 106 is shown after first and second ion bombardment steps have been performed on the sides 124 and 126 of a photoresist structure 120. A significant amount of photoresist material has been removed from both sides 124 and 126 of each photoresist structure 120. Figure 2A Compared to the photoresist structure 120 in the previous section, this corresponds to reducing the lateral width of the photoresist structure 120. With Figure 2A Compared to the width W1 of the photoresist structure 120, Figure 2H The width W1 of the photoresist structure 120 in the image is significantly reduced. Correspondingly, Figure 2H The width W2 of the groove 128 in the middle is relative to Figure 2A The width W2 of the groove 128 in the middle is significantly increased.

[0060] The changes in widths W1 and W2 can be achieved Figure 2K and Figure 2L I saw it in the middle. Figure 2K yes Figure 2AA top view of wafer 106 during the processing stage. Figure 2K The top view shows the photoresist structure 120 extending along the Y dimension. Figure 2K The top view also shows the grooves 128 between the photoresist structures 120. Figure 2L The image shows the result after the first and second ion bombardment steps were performed on the sides 124 and 126 of the photoresist structure 120. Figure 2H Wafer 106 in the processing stage. From Figure 2K and Figure 2L It can be seen from this that Figure 2L The width W1 of the photoresist structure 120 in the X dimension is significantly smaller than that in the photoresist structure 120. Figure 2K .from Figure 2K and Figure 2L It can be seen from this that Figure 2L The width W2 of the groove 128 between the photoresist structures in the X dimension is significantly larger than that in the X dimension. Figure 2K . Figure 2K The interception is shown Figure 2A The cutting line A of the cross section. Figure 2L The interception is shown Figure 2H The cutting line H of the cross section.

[0061] In some embodiments, when viewed from above, trench 128 may initially be a circular or other arcuate aperture. After the ion bombardment step, the circular or other arcuate aperture may be elongated in one or both of the X and Y directions.

[0062] Returning to the cross-sectional view, Figure 2I Corresponding to Figure 2H The processing stage following the view. Figure 2I In this process, trenches 130 have already been opened in the substrate 122. The trenches 130 are opened using an etching process. This etching process etches the portion of the substrate 122 exposed by the photoresist structure 120. Therefore, the photoresist structure 120 acts as a mask for patterning the substrate 122. The etching process can be selected based on the material of the substrate 122. The etching process can include wet etching, dry etching, or other types of etching.

[0063] exist Figure 2J In this process, metal has been deposited in trench 130 to form metal line 132. The metal may include tungsten, titanium, aluminum, copper, gold, its nitrides, tantalum nitride, or other types of metals. The photoresist material 120 is removed and a chemical mechanical planarization process is performed to make the top surface of the metal line 132 flush with the top surface of the substrate 122. Figure 2I and Figure 2JThe process described is merely one example of a process step that can be performed using a fully patterned photoresist structure 120 as a mask. Other processes may be performed without departing from the scope of this disclosure.

[0064] Figures 2A-2H The foregoing description illustrates an embodiment in which a multi-step ion bombardment process includes changing the bombardment angle between ion bombardment steps. However, other multi-step ion bombardment processes can be performed according to the principles of this disclosure. Reference will be made below. Figure 2B and Figure 2D Some of these processes are described. However, these other processes can use different process parameters and sequences than those described above. For example, other processes can use different angles, dosages, energies, or other parameters. Furthermore, these other processes may result in different shapes or profiles of the remaining photoresist structure 120. Figure 2B and Figure 2D The reference does not limit other processes to the previous reference. Figure 2B and Figure 2D Features shown and described

[0065] In one embodiment, the ion bombardment process includes a first ion bombardment step and a second ion bombardment step. The ion energy changes between the first and second ion bombardment steps. In this example, both ion bombardment steps are performed at sufficiently small bombardment angles so that no shadowing occurs in either step. Both ion bombardment steps can be referenced. Figure 2D Visualization is performed where the angle θ2 is small enough to ensure no shadowing occurs. The first ion bombardment step in the current embodiment is... Figure 2D The difference between the ion bombardment steps shown is that, in the current embodiment, no material is removed prior to the first ion bombardment step. Without departing from the scope of this disclosure, angles other than θ2 may be used in embodiments where the ion energy is varied between steps.

[0066] The first ion bombardment step of the first side 124 is performed with a relatively low ion energy. The entire first side 124 is bombarded by low-energy ions. The low ion energy results in little or no removal of photoresist material from the first side 124. However, as will be described in more detail below, the low ion energy reduces hardening.

[0067] Following the first ion bombardment step on the first side surface 124, a second ion bombardment step is performed on the first side surface 124. The second ion bombardment step is at the same angle as the first ion bombardment step. The second ion bombardment step includes a second ion energy. The second ion energy is higher than the first ion energy. The result of the second ion bombardment step is the removal of photoresist material from both the entire upper and lower portions of the first side surface 124. This can result in a profile of the first side surface 124 that is larger than... Figure 2E It is flatter as shown.

[0068] In one embodiment, the photoresist is a polymeric material comprising polymer chains. The polymeric material hardens when high-energy ions bombard the polymer and cause adjacent polymer chains to fuse. This fusion hardens the polymer and makes it more difficult to remove. However, lower-energy ions do not have enough energy to fuse adjacent polymer chains, instead causing the polymer chains to loosen or break. When bombarded with high-energy ions, the loose polymer chains do not fuse. Instead, the loose polymer chains are broken down and removed by the high-energy ions. Therefore, if the polymer chains are first loosened using lower-energy ions, subsequent bombardment with high-energy ions will remove the loose polymer chains without hardening them.

[0069] In one embodiment, the first ion energy is between 0.5 keV and 2.0 keV. If the first ion energy is higher than this range, a hardening effect may occur. If the first ion energy is lower than this range, there is essentially no effect on the photoresist. The second ion energy is between 4 keV and 8 keV. If the second ion energy is lower than this range, very little photoresist material can be removed from the first side 124. If the second ion energy is higher than this range, excessive photoresist material may be removed from the first side 124. In one example, the first ion energy is 1.0 keV and the second ion energy is 6 keV. Other ion energies may be used for the first and second ion bombardment steps without departing from the scope of this disclosure. The durations of the first and second ion bombardment steps may be the same or different from each other.

[0070] After performing the first and second ion bombardment steps on the first side 124 at low and high ion energies respectively, as referenced Figure 2F As described, wafer 106 is rotated 180°. Then, low-energy and high-energy ion bombardment steps are performed on the second side 126.

[0071] In one embodiment, the first low-energy ion bombardment step may have a first ion dose, and the second high-energy ion bombardment step may have a second ion dose different from the first ion dose. The second ion dose may be higher than the first ion dose. In one example, the first low-energy ion dose is between 1E14 and 2E15 ions. If the first low-energy ion dose is below this range, the effect on the photoresist structure 122 may be minimal. If the first low-energy ion dose is above this range, hardening may occur. In one example, the second ion dose is between 2E15 and 1E16 ions. If the second high-energy ion dose is below this range, very little photoresist material may be removed. If the second high-energy ion dose is above this range, excessive photoresist material may be removed. Other doses may be used without departing from the scope of this disclosure.

[0072] In another embodiment, in which the ion bombardment angle changes between the first and second ion bombardment steps, such as Figure 2B and Figure 2D As shown, the ion energy also changes between the first and second ion bombardment steps. Specifically, in the first high-incident-angle ion bombardment step, the ions can have the low ion energy described above. In the second low-incident-angle ion bombardment step, the ions can have the high energy described above.

[0073] More than two ion bombardment steps can be performed on each side 124 and 126. For example, in one embodiment, three ion bombardment steps can be performed on each side 124 and 126. The first ion bombardment step is performed at a high incident angle, such as... Figure 2B As shown. The first ion bombardment step has low ion energy. The second ion bombardment step is performed at a low incident angle, as... Figure 2D As shown. The second ion bombardment step is also performed at low ion energy. The third ion bombardment step is performed at a low incident angle (e.g., Figure 2D (As shown), it is executed with high ion energy.

[0074] In another embodiment, three ion bombardment steps can be performed on each side 124 and 126. The first ion bombardment step is performed at a high incident angle, such as... Figure 2B As shown. The first ion bombardment step has low ion energy. The second ion bombardment step is performed at a high incident angle, as... Figure 2B As shown. The second ion bombardment step is performed at high ion energy. The third ion bombardment step is performed at a low incident angle (e.g., Figure 2D (As shown), it is executed with high ion energy.

[0075] In another embodiment, three or more ion bombardment steps may be performed on each side 124 and 126. Each of the three or more ion bombardment steps may have a different bombardment angle. In another embodiment, each of the three or more ion bombardment steps may have a different bombardment energy.

[0076] Figure 3 Figure 300 illustrates the relationship between photoresist removal and trenching for various ion bombardment processes. Therefore, the X-axis corresponds to... Figure 2A The initial width W2 of the trench is shown. The Y-axis corresponds to the change in width W1 of the photoresist structure 120 after ion bombardment is performed on both the first side surface 124 and the second side surface 126. Line 302 corresponds to a multi-step process in which the first ion bombardment step is a high-incident-angle ion bombardment step and the second ion bombardment step is a low-incident-angle ion bombardment step. Line 304 corresponds to a single-step process in which ion bombardment is performed only at a high-incident-angle. Line 306 corresponds to a multi-step process in which the first ion bombardment step is a low-incident-angle ion bombardment step and the second ion bombardment step is a high-incident-angle ion bombardment step. Line 306 also corresponds to a single-step process in which ion bombardment is performed only at a low-incident-angle.

[0077] Group 310 identifies data points for each line with the lowest initial width W2. The shading effect is strongest in this case because the photoresist structures 120 are relatively close together. It can be seen that line 302 always results in the removal of a larger amount of photoresist material compared to other processes. Therefore, a multi-step process (such as using a high incident angle followed by a low incident angle) is preferred. Figures 2A-2H (As shown) can be very beneficial.

[0078] Although not shown in the figure, the process, which includes a first ion bombardment step with low energy and a high dose, and a second ion bombardment step with high energy and a low dose, provides greater photoresist material removal than other combinations of energy and dose.

[0079] Figures 4A-4D This is a top view of an integrated circuit 106 according to some embodiments, including elongated trenches 128 formed in a photoresist. Figures 4A-4D The relative widths of the trench 128 in the X direction are shown for various ion bombardment energies and doses. Figure 4A In the process, no ion bombardment was performed after the initial formation of the trench 128 in the photoresist 120.

[0080] exist Figure 4B In this study, a single ion bombardment step was performed using an ion energy of 6 keV and an ion dose of 4E15. The width of trench 128 in the X direction is... Figure 4A The groove 128 is wider.

[0081] exist Figure 4C In this process, a two-step ion bombardment process was performed. The first ion bombardment step had an energy of 6 keV and a dose of 1E15. The second ion bombardment step had an energy of 1 keV and a dose of 3E15. Figure 4C The groove 128 is higher than Figure 4B The groove 128 is wider. Therefore, Figure 4C The two-step ion bombardment process is more efficient than traditional methods. Figure 4B The single-step process removes more photoresist.

[0082] exist Figure 4D In this process, a two-step ion bombardment process was performed. The first ion bombardment step had an energy of 1 keV and a dose of 3E15. The second ion bombardment step had an energy of 6 keV and a dose of 1E15. Figure 4D The groove 128 is larger in the X direction than Figure 4C The groove 128 is wider. Therefore, Figure 4D The two-step ion bombardment process (where low-energy ions and a high dose are used in the first step, and high-energy ions and a low dose are used in the second step) results in a greater... Figure 4C The two-step process (in which high-energy ions and low dose are used in the first step, and low-energy ions and high dose are used in the second step) removes more photoresist.

[0083] Figures 4A-4D This is a top view of an integrated circuit 106 according to some embodiments, including elongated trenches 128 formed in a photoresist. Figures 4A-4D The relative widths of the trench 128 in the X direction are shown for various ion bombardment energies and doses. Figure 4A In the process, no ion bombardment was performed after the initial formation of the trench 128 in the photoresist 120.

[0084] Figures 5A-5D This is a top view of an integrated circuit 106 according to some embodiments, including an approximately circular trench 128 formed in a photoresist 120. Figures 5A-5D Using references Figures 4A-4D The described process. Specifically, in Figure 5A The ion bombardment process was not performed. Figure 5B In the middle, it was executed with Figure 4B The same ion bombardment process. In Figure 5C In the middle, it was executed with Figure 4C The same ion bombardment process. In Figure 5D In the middle, it was executed with Figure 4D The same ion bombardment process. From Figures 5A to 5DThe groove width gradually increases in the X direction, similar to... Figures 4A-4D . Figure 6 This is a perspective view of a wafer 106 according to one embodiment. Wafer 106 includes a substrate 120. Photoresist 120 has been deposited on the substrate 120, and trenches 128 have been formed in the photoresist 120 by a photolithography process. Figure 6 In this process, an ion bombardment step was performed. Ions 129 bombarded the photoresist 120. The ion bombardment step can have any of the characteristics or parameters of the aforementioned ion bombardment steps. The ion bombardment step can be a first ion bombardment step, a second ion bombardment step, or another ion bombardment step in the ion bombardment process. The result of the ion bombardment process is the widening of the trench 128. From Figure 6 As can be seen, in the X direction, groove 128 is nearly circular. Figures 2A-2K The groove 128 shown can also be circular in a similar manner.

[0085] Figure 7 yes Figure 1 A block diagram of the control system 112 is provided. The control system 112 includes processing resources 140, memory resources 142, and communication resources 144. Processing resources 140 may include one or more processors. Memory resources 142 may include one or more memories, which include components for controlling the ion source 108 and... Figure 1 The software instructions for other components of the semiconductor process system 100. When the processor executes the software instructions stored in memory, the control system 112 performs processes for controlling the semiconductor process system. These processes may include performing multiple ion bombardment steps and wafer rotation as previously described.

[0086] The control system 112 also includes communication resources 144. Communication resources may include a wireless transceiver, a wired connection, and circuitry for outputting and receiving signals via the wireless transceiver and / or the wired connection. Therefore, communication resources 144 can relay commands for controlling components of the semiconductor process system 100.

[0087] Figure 8 This is a flowchart of a method 800 for performing a semiconductor process according to one embodiment. Method 800 can be utilized with reference to... Figures 1-6 The system, structure, components, and process are described. In 802, the method includes depositing a photoresist on a substrate, an example of which is... Figure 2A Substrate 122. In 804, method 800 includes forming trenches in a photoresist, an example of which is... Figure 2A The trench 128. In 806, method 800 includes widening the trench by bombarding a first side of the trench with ions from a first angle. An example of the first side is... Figure 2BThe photoresist structure 120 has a side surface 124. In 808, method 800 includes widening the trench by bombarding the first side surface of the trench with ions from a second angle, wherein the second angle is different from the first angle.

[0088] Figure 9 This is a flowchart of a method 900 for performing a semiconductor process according to one embodiment. Method 900 can be utilized with reference to... Figure 1 Figure 5 illustrates the system, structure, components, and process. In method 900 (902), the process includes depositing a photoresist on a substrate. An example of a substrate is... Figure 2A Substrate 122. In 904, method 900 includes forming a photoresist structure by patterning the photoresist. An example of a photoresist structure is... Figure 2A The photoresist structure 120. In method 906, method 900 includes reducing the width of the photoresist structure by bombarding a first side of the photoresist structure with ions having a first energy. An example of the first side is... Figure 2B The photoresist structure 122 has a side surface 124. In 909, method 900 includes bombarding the first side surface of the photoresist structure with ions having a first energy, and then bombarding the first side surface of the photoresist structure with ions having a second energy, wherein the second energy is different from the first energy.

[0089] In one embodiment, a method includes depositing a photoresist on a substrate, forming a trench in the photoresist, and widening the trench by bombarding a first side of the trench with ions from a first angle and bombarding the first side of the trench with ions from a second angle different from the first angle.

[0090] In one embodiment, a method includes depositing a photoresist on a substrate and forming a photoresist structure by patterning the photoresist. The method includes reducing the width of the photoresist structure by bombarding a first side of the photoresist structure with ions having a first energy, and after bombarding the first side of the photoresist structure with ions having the first energy, bombarding the first side of the photoresist structure with ions having a second energy different from the first energy.

[0091] In one embodiment, a system includes a semiconductor processing chamber; a wafer support configured to support a wafer within the semiconductor processing chamber; an ion source positioned to bombard the wafer with ions; and a control system coupled to the ion source. The control system includes at least one processor and at least one memory coupled to the at least one processor, the at least one memory having instructions stored therein that, when executed by one or more processors, cause the ion source to: bombard the sides of a photoresist structure on the wafer from a first angle in a first ion bombardment step; bombard the sides of the photoresist structure on the wafer from the first angle in a second ion bombardment step; and bombard the sides of the photoresist structure from a second angle different from the first angle in a third ion bombardment step.

[0092] The various embodiments described above can be combined to provide further embodiments. If necessary, aspects of the embodiments can be modified to incorporate concepts from various patents, applications, and publications to provide even more advanced embodiments.

[0093] Based on the detailed description above, these and other changes can be made to the embodiments. Generally, the terminology used in the following claims should not be construed as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be interpreted to include all possible embodiments and the full scope of equivalents entitled to be obtained by those claims. Therefore, the claims are not limited to this disclosure.

[0094] Example 1 is a method for a semiconductor process, comprising: depositing a photoresist on a substrate; forming a trench in the photoresist; and widening the trench by bombarding a first side of the trench with ions from a first angle and bombarding the first side of the trench with ions from a second angle different from the first angle.

[0095] Example 2 is the method of Example 1, further comprising widening the trench by: bombarding a second side of the trench with ions from the first angle; and bombarding the second side of the trench with ions from a second angle different from the first angle.

[0096] Example 3 is the method of Example 2, further comprising: rotating the substrate 180 degrees between bombarding the first side and the second side.

[0097] Example 4 is the method described in Example 1, wherein the first angle is greater than the second angle relative to the vertical direction.

[0098] Example 5 is the method described in Example 4, wherein the first angle is between 55 and 65 degrees relative to the vertical direction, and the second angle is between 40 and 50 degrees relative to the vertical direction.

[0099] Example 6 is the method described in Example 5, wherein the first angle is 60 degrees and the second angle is 45 degrees.

[0100] Example 7 is the method described in Example 1, wherein bombarding the first side of the trench with ions from the first angle includes: bombarding the first side of the trench with ions having a first energy, wherein bombarding the first side of the trench with ions from the first angle includes: bombarding the first side of the trench with ions having a second energy greater than the first energy.

[0101] Example 8 is the method described in Example 7, wherein the first energy is between 0.5 keV and 2 keV, and wherein the second energy is between 4 keV and 8 keV.

[0102] Example 9 is the method of Example 1, wherein bombarding the first side of the trench with ions from the first angle includes: bombarding the first side of the trench with a first dose of ions, wherein bombarding the first side of the trench with ions from the first angle includes: bombarding the first side of the trench with a second dose of ions greater than the first dose.

[0103] Example 10 is the method of Example 1, further comprising, after widening the trench: etching the substrate using the photoresist as a mask; and depositing metal in the substrate.

[0104] Example 11 is the method described in Example 1, wherein the ion is an argon ion.

[0105] Example 12 is a method for a semiconductor process, comprising: depositing a photoresist on a substrate; forming a photoresist structure by patterning the photoresist; and reducing the width of the photoresist structure by bombarding a first side of the photoresist structure with ions having a first energy, and after bombarding the first side of the photoresist structure with ions having the first energy, bombarding the first side of the photoresist structure with ions having a second energy different from the first energy.

[0106] Example 13 is the method of Example 12, further comprising reducing the width of the photoresist structure by bombarding a second side of the photoresist structure with ions having the first energy; and after bombarding the second side of the photoresist structure with ions having the first energy, bombarding the second side of the photoresist structure with ions having the second energy.

[0107] Example 14 is the method described in Example 13, wherein the first energy is between 0.5 keV and 2 keV, and wherein the second energy is between 4 keV and 8 keV.

[0108] Example 15 is the method of Example 12, wherein bombarding the first side of the photoresist structure with ions having the first energy includes: bombarding the first side of the photoresist structure with a first dose of ions, wherein bombarding the first side of the photoresist structure with ions having the first energy includes: bombarding the first side of the photoresist structure with a second dose of ions less than the first dose.

[0109] Example 16 is a system for a semiconductor process, comprising: a semiconductor processing chamber; a wafer support configured to support a wafer in the semiconductor processing chamber; an ion source positioned to bombard the wafer with ions; and a control system coupled to the ion source, the control system comprising: at least one processor; and at least one memory coupled to the at least one processor, the at least one memory having instructions stored therein, the instructions, when executed by the one or more processors, causing the ion source to: bombard a side of a photoresist structure on the wafer from a first angle in a first ion bombardment step, bombard the side of the photoresist structure from the first angle in a second ion bombardment step, and bombard the side of the photoresist structure from a second angle different from the first angle in a third ion bombardment step.

[0110] Example 17 is the system described in Example 16, wherein the first ion bombardment step and the second ion bombardment step have the same first energy.

[0111] Example 18 is the system described in Example 17, wherein the third ion bombardment step has a second energy higher than the first energy.

[0112] Example 19 is the system described in Example 16, wherein the second ion bombardment step and the third ion bombardment step have the same first energy.

[0113] Example 20 is the system described in Example 17, wherein the first ion bombardment step has a second energy lower than the first energy.

Claims

1. A method for semiconductor processing, comprising: Deposit photoresist on the substrate; Grooves are formed in the photoresist; The groove can be widened by the following methods: The trench is bombarded with ions from a first angle on its first side surface, and The first side of the trench is bombarded with ions from a second angle different from the first angle. Wherein, the first angle is determined such that the lower part of the first side is not bombarded by ions, while the upper part of the first side is bombarded by ions, and the second angle is determined such that both the lower and upper parts of the first side are bombarded by ions, and wherein the ions from the first angle have a first energy that does not remove the photoresist but reduces the hardening of the photoresist, and the ions from the second angle have a third energy different from the first energy that removes a portion of the photoresist.

2. The method of claim 1, further comprising widening the trench by means of: The second side of the trench is bombarded with ions from the first angle; and The second side of the trench is bombarded with ions from a second angle different from the first angle.

3. The method according to claim 2, further comprising: The substrate is rotated 180 degrees between bombarding the first side and the second side.

4. The method according to claim 1, wherein, The first angle is greater than the second angle relative to the vertical direction.

5. The method according to claim 4, wherein, The first angle is between 55 and 65 degrees relative to the vertical direction, wherein the second angle is between 40 and 50 degrees relative to the vertical direction.

6. The method according to claim 5, wherein, The first angle is 60 degrees, and the second angle is 45 degrees.

7. The method according to claim 1, wherein, Bombarding the first side of the trench with ions from the first angle includes: bombarding the first side of the trench with ions having a first energy, wherein bombarding the first side of the trench with ions from the first angle includes: bombarding the first side of the trench with ions having a second energy greater than the first energy.

8. The method according to claim 7, wherein, The first energy is between 0.5 keV and 2 keV, and the second energy is between 4 keV and 8 keV.

9. The method according to claim 1, wherein, Bombarding the first side of the trench with ions from the first angle includes: bombarding the first side of the trench with a first dose of ions, wherein bombarding the first side of the trench with ions from the first angle includes: bombarding the first side of the trench with a second dose of ions greater than the first dose.

10. The method of claim 1, further comprising, after widening the trench: The substrate is etched using the photoresist as a mask; and Metal is deposited in the substrate.

11. The method according to claim 1, wherein, The ion is an argon ion.

12. A method for semiconductor processing, comprising: Deposit photoresist on the substrate; The photoresist structure is formed by patterning the photoresist; The width of the photoresist structure can be reduced by the following methods: The first side of the photoresist structure is bombarded from a first angle with ions of a first energy, and After bombarding the first side of the photoresist structure with ions having the first energy from the first angle, the first side of the photoresist structure is then bombarded with ions having a second energy different from the first energy from a second angle different from the first angle. Wherein, the first angle is determined such that the lower part of the first side is not bombarded by ions, while the upper part of the first side is bombarded by ions, and the second angle is determined such that both the lower and upper parts of the first side are bombarded by ions, and wherein, the first energy does not remove the photoresist structure, but reduces the hardening of the photoresist structure, and the second energy removes a portion of the photoresist structure.

13. The method of claim 12, further comprising reducing the width of the photoresist structure by: The second side of the photoresist structure is bombarded with ions having the first energy; and After bombarding the second side of the photoresist structure with ions having the first energy, the second side of the photoresist structure is bombarded with ions having the second energy.

14. The method according to claim 13, wherein, The first energy is between 0.5 keV and 2 keV, and the second energy is between 4 keV and 8 keV.

15. The method according to claim 12, wherein, Bombarding the first side of the photoresist structure with ions having the first energy includes: bombarding the first side of the photoresist structure with a first dose of ions, wherein bombarding the first side of the photoresist structure with ions having the first energy includes: bombarding the first side of the photoresist structure with a second dose of ions less than the first dose.

16. A system for semiconductor processing, comprising: Semiconductor processing room; A wafer support is configured to support a wafer in the semiconductor processing chamber; An ion source is configured to bombard the wafer with ions; as well as A control system coupled to the ion source, and the control system includes: At least one processor; and At least one memory, coupled to the at least one processor, the at least one memory having instructions stored therein, the instructions, when executed by the one or more processors, causing the ion source to: bombard the side surface of the photoresist structure on the wafer from a first angle in a first ion bombardment step, bombard the side surface of the photoresist structure from the first angle in a second ion bombardment step, and bombard the side surface of the photoresist structure from a second angle different from the first angle in a third ion bombardment step. Wherein, the first angle is determined such that the lower part of the side is not bombarded by ions, while the upper part of the side is bombarded by ions, and the second angle is determined such that both the lower and upper parts of the side are bombarded by ions, and wherein, the ions from the first angle have a first energy that does not remove the photoresist structure but reduces the hardening of the photoresist structure, and the ions from the second angle have a second energy different from the first energy that removes a portion of the photoresist structure.

17. The system according to claim 16, wherein, The second energy is greater than the first energy.

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