Optimized saddle nozzle design for gas injection systems

Abstract

A gas injection nozzle comprising an elongate gas conduit, the elongate gas conduit comprising: a first gas conduit section configured to couple with a gas reservoir; a second gas conduit section fluidly coupled to the first gas conduit section and defining a downward curve of the elongated gas conduit; a third gas conduit section defining an upward curve of the elongated gas conduit, the third gas conduit section extending to a sealed end and disposed in mirror image relationship with at least a portion of the second gas conduit; and a central gas conduit section coupled between the second gas conduit section and the third gas conduit section, the central gas conduit section has a first aperture formed in an upper surface of the central gas conduit and a second aperture formed in a lower surface of the central gas conduit directly opposite the first aperture and larger than the first aperture, wherein the elongate gas conduit has a first diameter along its length comprising at least a portion of the second gas conduit section, the third gas conduit section, and the central gas conduit section, and wherein the central gas conduit section comprises a substantially horizontal portion extending on each side of the first aperture and the second aperture by a distance of at least two times the first diameter of the gas conduit.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. patent application Ser. No. 17 / 945,338, filed on Sep. 15, 2022, the contents of which are incorporated herein by reference in their entirety. Background Art

[0003] In the study of electronic materials and the processes of fabricating such materials into electronic structures, specimens of electronic structures may be used for microscopic examination for failure analysis and device verification. For example, specimens of wafers such as silicon, gallium nitride, or other types of wafers including one or more integrated circuits (ICs) or other electronic structures formed thereon may be milled with a focused ion beam (FIB) and / or analyzed with a scanning electron microscope (SEM) to study specific characteristics of the circuits or other structures formed on the wafer.

[0004] FIB and SEM tools are similar in that each tool includes a charged particle column that generates a charged particle beam and directs the beam toward the sample. However, as the names imply, the charged particle beam generated by a FIB column is a focused beam of ions, while the charged particle beam generated by a SEM column is a focused beam of electrons.

[0005] Although FIB and SEM tools (as well as FIB-SEM tools, including FIB columns and SEM columns) are typically used to analyze and otherwise evaluate structures within a sample, these tools can also be used to etch or deposit materials on a sample. For example, a focused ion beam can be scanned over a sample surface, and a gas injection system directs a flow of a deposition precursor gas to the scanned area to selectively deposit materials in the scanned area with nanometer precision according to a technique commonly referred to as focused ion beam enhanced deposition or simply FIB enhanced deposition. In a FIB enhanced deposition process, molecules of the injected gas adhere to the sample surface. As the ion beam scans an area of ​​the sample, the energy released by the collision cascade of the impacting ions causes the precursor molecules adsorbed on the surface to dissociate, resulting in solid deposition on the surface, along with the release of volatile residues. As another example, a deposition gas can be introduced into the vicinity of the sample, where an electron beam is scanned over the sample surface to deposit material under the SEM column.

[0006] While FIB enhanced deposition has been used in many different instances and applications, improved deposition techniques are continually sought. Summary of the invention

[0007] Embodiments of the present disclosure relate to an improved method and system for charged particle beam enhanced deposition, such as focused ion beam enhanced deposition. Embodiments can be used to increase the deposition rate of charged particle beam enhanced deposition, thereby increasing the yield of the process using charged particle beam enhanced deposition. Embodiments can also provide a highly symmetrical gas flow around the optical axis of the charged particle beam, thereby reducing any potential "shadow effect" generated during the deposition process. Although embodiments of the present disclosure can be used to increase the rate of depositing materials on various different types of samples, some embodiments are particularly useful in depositing materials on samples of semiconductor wafers or similar specimens.

[0008] In some embodiments, a gas injection nozzle including an elongated gas conduit is provided. The elongated gas conduit may include: a first gas conduit section configured to be coupled to a gas reservoir; a second gas conduit section fluidly coupled to the first gas conduit section and defining a downward curve of the elongated gas conduit; a third gas conduit section defining an upward curve of the elongated gas conduit, the third gas conduit section extending to a sealed end and disposed in a mirrored relationship with at least a portion of the second gas conduit; and a central gas conduit section coupled between the second gas conduit section and the third gas conduit section. The central gas conduit section may have a first hole formed in an upper surface of the central gas conduit and a second hole formed in a lower surface of the central gas conduit directly opposite the first hole and larger than the first hole. In addition, this elongated gas conduit may have an inner diameter along its length that includes at least this second gas conduit section, this third gas conduit section and a portion of this central gas conduit section, and this central gas conduit section may include a substantially horizontal portion extending on each side of this first hole and this second hole a distance at least twice that of this inner diameter of this gas conduit.

[0009] In some embodiments, a system for depositing a material on a sample in a localized region of the sample is provided. The system may include: a vacuum chamber; a sample support configured to hold the sample in the vacuum chamber during a sample evaluation procedure; a charged particle beam column configured to direct a charged particle beam into the vacuum chamber toward the sample so that the charged particle beam collides with the sample in a deposition region; and a gas injection system configured to deliver a process gas to the deposition region of the sample. The gas injection system may include an elongated gas conduit, the elongated gas conduit comprising: a first gas conduit section configured to be coupled to a gas reservoir; a second gas conduit section fluidly coupled to the first gas conduit section and defining a downward curve of the elongated gas conduit; a third gas conduit section defining an upward curve of the elongated gas conduit, the third gas conduit section extending to a sealed end and disposed in a mirrored relationship with at least a portion of the second gas conduit; and a central gas conduit section coupled between the second gas conduit section and the third gas conduit section. The central gas conduit section may have a first hole formed in an upper surface of the central gas conduit and a second hole formed in a lower surface of the central gas conduit that is larger than the first hole and directly opposite the first hole. The elongated gas conduit may also have an inner diameter along its length that includes at least the second gas conduit section, the third gas conduit section, and a portion of the central gas conduit section, and the central gas conduit section may include a substantially horizontal portion that extends on each side of the first hole and the second hole a distance at least twice the inner diameter of the gas conduit.

[0010] In some embodiments, a method for depositing material on a sample in a deposition region of the sample using a charged particle beam column is provided. The method may include positioning the sample in a vacuum chamber so that the deposition region is under the field of view of the charged particle beam column; injecting a deposition precursor gas into the vacuum chamber at a location adjacent to the deposition region using a gas injection system including an elongated gas conduit; generating a charged particle beam using the charged particle beam column and focusing the particle beam in the deposition region of the sample; and scanning the focused particle beam over the deposition region of the sample to activate molecules of the deposition gas that have adhered to the surface of the sample in the deposition region and deposit material on the sample in the deposition region. The elongated gas conduit may include various features described above.

[0011] In various embodiments, the gas injection nozzle may include one or more of the following additional features. The diameter of the second hole is at least twice the diameter of the first hole. The substantially horizontal portion of the central gas conduit extends on each side of the first hole and the second hole for a distance at least three times the inner diameter of the gas conduit. The elongated gas conduit comprises stainless steel. The inner diameter of the elongated gas conduit is substantially constant over the entire length of the elongated gas conduit. The inner diameter of the elongated gas conduit is between 1500 and 300 microns. The inner diameter of the elongated gas conduit is between 1000 and 600 microns.

[0012] In order to better understand the nature and advantages of the present disclosure, reference should be made to the following description and accompanying drawings. However, it should be understood that each of the accompanying drawings is provided for illustrative purposes only, is not drawn to scale, and is not intended to be a definition of the limitations of the scope of the present disclosure. In addition, as a general rule, and unless otherwise apparent in the specification, where the same reference numerals are used for elements in different drawings, these elements are generally the same or at least similar in function or purpose. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a simplified schematic diagram of the sample particle beam deposition system;

[0014] Figure 2 is a simplified schematic diagram of a previously known gas injection system;

[0015] Figure 3 is a simplified illustration of a portion of a gas injection system according to some embodiments disclosed herein;

[0016] Figure 4A According to some embodiments Figure 3 A simplified cross-sectional view of a gas conduit shown in ;

[0017] Figure 4B According to some embodiments Figure 3 an enlarged view of a portion of a gas conduit shown in;

[0018] Figure 4C is a simplified illustration of a portion of a gas injection system according to some embodiments disclosed herein;

[0019] Figure 5A Simplified diagram illustrating an example of a shadowing effect that may occur during a charged particle deposition operation using some previously known gas jet nozzles;

[0020] Figure 5B A simplified diagram illustrating the absence of shadowing effects in a charged particle deposition operation using a gas jet nozzle according to an embodiment disclosed herein;

[0021] Figure 6 A flowchart describing steps associated with a method of depositing a material on a sample using a focused ion beam according to some embodiments; and

[0022] Figure 7 is a simplified illustration of a sample that may have material deposited on a portion of the sample according to embodiments disclosed herein. DETAILED DESCRIPTION

[0023] Embodiments of the present disclosure relate to an improved method and system for charged particle beam enhanced deposition, such as focused ion beam enhanced deposition. Embodiments can be used to increase the deposition rate of charged particle beam enhanced deposition, thereby increasing the yield of processes using charged particle beam enhanced deposition. In some cases, embodiments can also be used to change the chemical composition of the deposited material, thereby improving the deposition process.

[0024] Example Focused Ion Beam (FIB) Tool

[0025] In order to better understand and comprehend the present disclosure, first refer to Figure 1 , Figure 1 FIG. 1 is a simplified schematic diagram of a previously known focused ion beam (FIB) evaluation system 100. The FIB system 100 may be used to perform particle-enhanced deposition of various materials on semiconductor wafers, among other operations.

[0026] like Figure 1 As shown, system 100 may include a vacuum chamber 110 and a focused ion beam (FIB) column 120, among other components. A support element 140 may support a sample 130 (e.g., a semiconductor wafer) within chamber 110 during a processing operation in which sample 130 (sometimes referred to herein as an "object" or "specimen") is subjected to a charged particle beam from FIB column 120.

[0027] During processing operations, one or more gases may be delivered to the chamber 110 by the gas injection system 150 for certain operations. For simplicity of description, the gas injection system 150 is Figure 1 150 is shown as a nozzle, but it should be noted that the gas injection system 150 may include a gas reservoir, a gas source, a valve, one or more inlets and one or more outlets, among other components. In some embodiments, the gas injection system 150 may be configured to deliver gas to a localized area of ​​the sample 130 that is exposed to the scan pattern of the charged particle beam, rather than delivering gas to the entire upper surface of the sample. For example, in some embodiments, the gas injection system 150 has a nozzle opening diameter measured in hundreds of microns (e.g., between 400 and 500 microns), which is configured to deliver gas directly to a relatively small portion of the sample surface that contains the scan pattern of the charged particle beam.

[0028] The FIB column 120 is connected to the vacuum chamber 110 so that the charged particle beam generated by the FIB column propagates through the vacuum environment formed in the vacuum chamber 110 before striking the sample 130. Figure 1 As shown, the FIB column 120 can generate a focused ion beam 125 that travels through the vacuum environment of the chamber 110 before colliding with the sample 130.

[0029] The FIB column 120 can mill (e.g., drill grooves) a sample 130 by irradiating the sample with a charged particle beam 125 to form a cross section and, if desired, smooth the cross section. The FIB milling process typically operates by positioning the sample in a vacuum environment and emitting a focused ion beam toward the sample to etch or mill away material from the sample. In some cases, the vacuum environment may be purged by a controlled concentration of background gases that are used to help control the etching rate and quality or to help control the deposition of substances. The accelerated ions may be generated from xenon, gallium, or other suitable elements and are typically accelerated toward the sample by a voltage in the range of 500 volts to 100,000 volts, and more typically in the range of 3,000 volts to 30,000 volts. The beam current is typically in the range of a few picoamps to a few microamps, depending on the FIB instrument configuration and application, and the pressure is typically controlled at 10 -10 to 10 -5 mbar.

[0030] The milling process can be achieved by, for example, (i) locating a location of interest that should be milled so as to remove a portion of material (e.g., a portion of one or more layers) from the sample, (ii) moving the sample (e.g., by mechanical support element 140) so that the sample is below the field of view of the FIB unit, and (iii) milling the sample to remove the desired amount of material in the location of interest. The milling process can include forming grooves (typically with lateral dimensions ranging from a few microns to several hundred microns) in the sample.

[0031] The milling process typically includes scanning a charged particle beam back and forth (e.g., in a raster or other scanning pattern) over a specific area of ​​the sample being imaged or milled. One or more lenses (not shown) coupled to the charged particle column can implement a scanning pattern known to those skilled in the art. The area scanned is typically a very small portion of the total area of ​​the sample. For example, the sample may be a semiconductor wafer having a diameter of 150 mm, 200 mm, or 300 mm, and each area scanned on the wafer (i.e., the milled area) may be a rectangular area having a width and / or length measured in microns or tens of microns. Each iteration (or frame) of the ion beam scanning over the milled area is typically measured in microseconds, and removes a very small amount of material (e.g., as low as 0.01 atomic layers using a low i probe (e.g., 10 pA) or as high as 1000 atomic layers using a high i probe (e.g., 1000 nA), so that the scanning pattern is repeated thousands or even millions of times to etch the hole to the desired depth.

[0032] During the milling operation, the charged particle beam 120 generated by the FIB column 120 propagates through the vacuum environment formed in the vacuum chamber 110 before striking the sample 130. The milling process produces byproducts such as molecules, atoms and ions of the milled material and secondary electrons. For example, when ions strike the sample surface at a relatively high energy level, the ions may begin a collision cascade, which transfers momentum and energy from the ions to the sample until the ions stop and are implanted. The momentum and energy transfer during the collision cascade may result in the dislocation of atoms, the ionization of atoms, and the generation of phonons (heat). The cascade may reach the sample surface, causing atoms with sufficient momentum and energy to sputter to escape the solid sample, and secondary ions and electrons are generated as a combination of ionization and sputtering, which also escape the sample surface. Secondary ions or secondary electrons may be detected by an appropriate detector (not shown). The detected secondary ions or secondary electrons may then be used to analyze the properties of the milled layers and structures.

[0033] Although Figure 1 Although not shown, the FIB system 100 may include one or more controllers, processors, or other hardware units that control the operation of the system 100 by executing computer instructions stored in one or more computer-readable memories, as known to those skilled in the art. For example, the computer-readable memory may include solid-state memory (e.g., random access memory (RAM) and / or read only memory (ROM), which may be programmable, flash-updateable, and / or the like), a disk drive, an optical storage device, or a similar non-transitory computer-readable storage medium.

[0034] Charged Particle Enhanced Deposition Process

[0035] Some embodiments of the present disclosure can deposit material on a sample positioned on a support 140 by starting a deposition process under the FIB column 120. For example, in some embodiments, the FIB column 120 can be used to start a focused ion beam enhanced deposition process in a deposition mode. To this end, a deposition gas can be supplied to the sample 130 by a gas injection system 150, and the energy from the FIB column 120 can generate an ion beam 125. The cascade of impinging ions can then activate the deposition gas, resulting in material being deposited on the sample, which is located in the sample area where the ion beam is scanned. Therefore, the deposition that occurs according to such embodiments does not occur simultaneously on the entire surface of the sample or wafer being processed. Instead, the deposition occurs only in the general area where the ion beam (as a non-limiting example, for xenon plasma, its diameter can be in the range of 0.5 to 25 microns) strikes the wafer, and when the ion beam is scanned on these areas of the wafer. Therefore, the deposition according to some embodiments can be performed with a resolution of microns.

[0036] The rate at which material is deposited in such a focused ion beam (FIB) enhanced deposition process can have a direct impact on the throughput of the process. Therefore, a higher deposition rate can equate to a higher throughput. During a FIB deposition process, the rate at which material is deposited on a sample depends on many different factors, including the energy level of the charged particle beam, the type of material on the sample surface, the temperature of the sample surface, and the precursor gases used for the deposition process.

[0037] The deposition rate may also be highly dependent on the gas flow rate from the gas jet nozzle opening and the gas concentration on the sample surface. For example, the goal of a FIB enhanced deposition process is often to have the highest concentration of precursor gas molecules at the scanning location of the ion beam (called the interaction point) on the sample surface. One system designed to provide high gas concentration is the dual perforated nozzle design described in U.S. Patent No. 6,992,288, which is incorporated herein in its entirety for all purposes.

[0038] Figure 2 FIG. 2 is a simplified illustration of the end of a gas nozzle 200 according to the teachings of the '288 patent. As discussed in the '288 patent, the gas nozzle 200 includes various parts, Figure 22. Only the end 210 thereof is shown in FIG. The end 210 includes a gas conduit 212 that extends the length of the gas nozzle. The gas conduit 212 is a conduit through which a gas injection system can deliver one or more gases from, for example, a gas reservoir (not shown) to a reaction zone above the sample 230. As shown, the end 210 has a u-shaped profile and includes a first hole 214 and a second hole 216 positioned within the bottom of the u-shape. The hole 214 is formed through the upper surface of the gas conduit 210, and the gas hole 216 is formed through the bottom surface of the gas conduit. The holes 214, 216 are aligned to define a space through which a primary electron beam or ion beam 215 can propagate.

[0039] The gas conduit 212 extends through the holes 214, 216, terminating at a sealed end 218 of the gas nozzle. The gas conduit 212 is shaped within the end 210 to allow a first portion 222 of the gas flowing through the conduit 212 to pass from a first direction and through the second hole 216, and to allow a second portion 224 of the gas flowing through the conduit 212 to propagate toward the sealed end and return through the gas conduit 212 and pass from a second direction and through the second hole 216. The first hole 214 is designed to be smaller than the second hole so that most of the gas should be exhausted through the second hole 216 (towards the surface of the sample 230) rather than the first hole 214. A portion of the gas is allowed to flow through the hole 216 so that it is reflected back through the gas conduit in the opposite direction, allowing the gas to exit the hole 216 in a substantially opposite direction.

[0040] Although nozzle 200 is a significant improvement over previously known gas nozzles for charged particle beam deposition, the u-shaped nature of end 210 surrounding aperture 216 may cause some gas molecules to arrive at aperture 216 at an average velocity in a slightly downward trajectory that is tilted away from the location of charged particle beam 215, as shown by arrows 222 and 224, which represent the path of gas over and through aperture 216. In addition, if the gas flow at arrow 222 is higher than the gas flow at arrow 224, the deposition rate of material deposited on sample 230 may drift horizontally to the right of the point where the ion beam collides with sample 230.

[0041] Improved gas injection nozzle

[0042] The embodiments disclosed herein flatten the area around the bottom hole of the gas conduit so that the gas molecules leave the hole without any horizontal orientation and so that the deposition of the gas molecules is highest at the center of the hole 216, rather than to the right. Thus, the embodiments described herein provide a gas injection system that further improves upon the teachings of the '288 patent. Figure 3FIG. 3 is a simplified illustration of a gas jet nozzle 300 according to some embodiments disclosed herein, which can be used in a charged particle deposition system (such as the system 100 discussed above) in place of the gas jet nozzle 200. Similar to the nozzle 200, the gas jet nozzle 300 includes various parts, including Figure 3 Only the end 310 of these parts is shown. The end 310 includes a gas conduit 312, although in Figure 3 Gas conduit 312 may be similar to gas conduit 212 and is a conduit through which a gas injection system may deliver one or more gases from, for example, a gas reservoir (not shown) to a reaction zone above sample 330.

[0043] As shown, end portion 310 also includes a first hole 314 and a second hole 316. Hole 314 is formed through the upper surface of gas conduit 310, and hole 316 is formed through the bottom surface of gas conduit. Holes 314, 316 are aligned to define a space through which a primary electron beam or ion beam 315 can propagate. As described in more detail below, in some embodiments, hole 316, which is spaced directly above the sample during the deposition process, is much larger than hole 314 to encourage gas flowing through the hole to exit hole 316 toward the sample. For example, in some embodiments, the diameter of hole 316 is twice as large as the diameter of hole 314 (and therefore four times as large in area).

[0044] The gas conduit 312 extends through the holes 314, 316, terminating at the sealed end 318 of the gas nozzle. Thus, similar to the gas conduit 212, the gas conduit 312 is shaped within the end 310 to allow a first portion 322 of gas flowing through the conduit 312 to pass from a first direction and through the second hole 316, and to allow a second portion 324 of gas flowing through the conduit 312 to propagate toward the sealed end and return via the gas conduit 312 and pass from a second direction and through the second hole 316.

[0045] Unlike the gas conduit 212, the gas conduit 312 includes a section 320 that is completely flat for a predetermined distance on each side of the hole 316. The flat section 320 has opposing top and bottom surfaces 326 and 328 that are horizontal and therefore perpendicular to the charged particle beam 315. Thus, when the sample 330 is a flat semiconductor wafer, the bottom surface 328 is spaced apart from and parallel to the sample surface. For illustration, reference is made to Figure 4A and Figure 4B ,in Figure 4A For reference Figure 4A and Figure 4B The gas conduit 312 is a simplified cross-sectional view for better understanding. Figure 4B FIG. 3 is an enlarged view of the flat section 320 of the gas conduit. It is worth noting that Figure 4Aand Figure 4B Not drawn to scale. Figure 4A As shown, in some embodiments, the gas conduit 312 has a circular cross-section. In various embodiments, the inner diameter (d) of the gas conduit 312 may be between 300 and 1500 mm, and in some embodiments, the inner diameter (d) may be between 600 and 1000 mm.

[0046] like Figure 4B As shown, the flat section 320 extends a distance (X) on each side of the holes 314, 316. In some embodiments, the distance X is at least two times the diameter of the gas conduit 312, and in some embodiments, the distance X is at least three times the diameter of the gas conduit 312. The flat section 320 forces the gas flow through the gas conduit 312 to be perpendicular to the charged particle beam 315 (and perpendicular to the opening 316), thereby creating a constant pressure throughout the gas conduit 312 in the area of ​​the hole 316. The constant pressure increases the gas flow downward, which causes the gas to leave the hole 316 without any horizontal drift to the left or right side of the hole, thereby ensuring that the concentration of gas molecules leaving the gas conduit 312 from the hole 316 is highest at the center of the hole (the interaction point during the deposition process) and symmetrical about the center of the hole, which in turn leads to more precise deposition on the sample.

[0047] Additionally, in some embodiments, holes 314, 316 can be made smaller than holes 214, 216. Although the embodiments described herein are not limited to any particular size of holes 314 and 316, as an illustrative example, in some embodiments, hole 314 has a diameter of 0.4 mm, while hole 316, which is twice as large as hole 314, has a diameter of 0.8 mm. Since top hole 314 is half as large as bottom hole 316, most of the gas in conduit 312 will be exhausted toward the surface of sample 330 through bottom hole 316, rather than through top hole 314.

[0048] In some embodiments, to further ensure that the deposition from the deposition process is centered directly below the aperture 316, the gas conduit 312 may be symmetrically shaped in the end 310 for electrostatic purposes so that the ion beam 315 is not undesirably reflected away from the center of the aperture 316. For illustration, refer to Figure 4C , which is a simplified illustration of a portion of the gas conduit 312, including the Figure 3 The end 310 and the middle (first) section 340 of the gas nozzle 300 in question are both not in the Figure 3 The middle section 330 may be connected to one or more gas reservoirs, gas valves and other components of the gas injection system ( Figure 4C316). As shown, the middle section 340 includes a portion located in a plane above the plane of the bottom of the end 310. The second gas conduit section 342, which is part of the end 310, fluidly couples the end to the middle section 340 and forms a downward bend in the gas conduit 312 before the gas hole 316. The second gas conduit section 342 is fluidly coupled at its other end to the central gas conduit section 344, which may include the flat section 320 of the gas conduit. Therefore, the central conduit section 344 may include a relatively long horizontal section as described above, wherein the holes 314 and 316 are formed in the central gas conduit portion, and in some embodiments are centered in the central gas conduit portion.

[0049] like Figure 4C As shown, the end 310 may also include a third gas conduit section 346 that is a mirror image of the second gas conduit section 342, thereby forming an upward bend of the gas conduit 312 after the hole 316 and the central gas conduit 344. In some embodiments, the gas conduit 312 can be made of a single metal piece. The gas conduit sections 342 and 346 can each be part of the gas conduit 312, and therefore part of the same single metal piece. The two sections 342 and 346 are symmetrical to each other and are fluidly coupled to the central gas conduit portion 344 and are disposed on opposite sides of the central gas conduit portion 344. The symmetrical arrangement of the second conduit section 342 and the third conduit section 346 provides improved electrostatic properties of the gas conduit 312 so that the ion beam 315 is not undesirably reflected away from the center of the hole 316.

[0050] Reduction of the "shadow effect"

[0051] As described above, a gas jet nozzle according to the present disclosure, such as gas jet nozzle 300, can provide a highly symmetrical gas flow around the interaction point between the charged particle beam and the sample. The highly symmetrical gas flow can reduce unwanted shadowing effects that may otherwise occur with deposition from gas jet nozzles that impart flux having a non-perpendicular angular component to the gas flow. For illustration, reference is first made to Figure 5A , which depicts local focused ion beam deposition on a sample 530 using a prior art gas jet nozzle (not shown). Figure 5AAs shown, sample 530 includes a groove 532 in which material is to be deposited by a FIB deposition process. However, gas flow 510 is at a slight angle relative to ion beam 520. Due to the angular flux of gas flow 510, corner 534 of groove 532 partially blocks some portions of the gas flow from reaching the area on the same side of the groove as corner 534. Therefore, in effect, corner 534 creates a "shadow" within the left side of groove 532, which causes deposited material 536 to be thicker on the right side of the groove than on the left side.

[0052] Figure 5B 5 is a simplified illustration of a charged particle deposition process according to the techniques described herein. As shown, a gas flow 515 that is highly symmetrical about the optical axis of the ion beam 520 and centered on the optical axis of the ion beam 520 flows into a groove 532 of a sample 530, and no portion of the gas flow is blocked or otherwise shielded by a corner 534. Therefore, the material 538 deposited in the groove can have a uniform thickness throughout the groove.

[0053] Although Figure 5A and Figure 5B The comparison illustrates how the embodiments disclosed herein provide improvements over previously known charged particle deposition processes with respect to shadowing effects when material is deposited within trenches, and one skilled in the art will appreciate that similar improvements can be obtained when the deposition process deposits layers on raised structures formed on a sample. For example, in this case, Figure 5A The shadowing effect imposed by the airflow 510 in the can result in more deposition on the front side of the raised structure that is in direct contact with the airflow, and less deposition on the back side of the structure where the structure itself "shadows" the airflow. Figure 5B The gas flow 515 shown in FIG. 5 can reduce or even eliminate shadowing effects because the gas flow is centered on and symmetric about the optical axis of the ion beam 520 .

[0054] Example FIB Deposition Process

[0055] To further illustrate the embodiments of the present disclosure, refer to Figure 6 and Figure 7 ,in Figure 6 is a flowchart describing steps associated with method 600 according to some embodiments, and Figure 7is a simplified illustration of a sample 700 that may be representative of sample 130. Material may be deposited on sample 700 via a charged particle beam enhanced deposition process according to method 600. Method 600 begins by positioning a sample within a processing chamber of a sample evaluation system (block 610). The processing chamber, which may be chamber 100, for example, may include one or more charged particle beam columns that may be operated in a deposition mode to deposit material in one or more localized regions on sample 700. Block 610 may include positioning sample 700 on a sample support, such as support 140, within a vacuum chamber.

[0056] In many cases, sample 700 will include multiple different areas where material is to be deposited. For example, Figure 7 A top view of a sample 700 and two expanded views of a particular portion of the sample 700 are depicted. The sample 700 may be, for example, a 150 mm, 200 mm, or 300 mm semiconductor wafer, and may include a plurality of integrated circuits 710 (52 in the depicted example) formed thereon. The integrated circuits 710 may be at an intermediate stage of fabrication, and the method 600 may be used to deposit material on one or more regions 720 of the integrated circuits. For example, Figure 7 Expanded view A of 710 depicts a plurality of regions 720 of an integrated circuit 710 on which material may be deposited according to the techniques described herein. Expanded view B depicts one of the regions 720 in greater detail.

[0057] Return to reference Figure 6 , the support 140 may be moved into position so that the area where material is to be deposited on the sample (e.g., one of the areas 720, referred to herein as the "deposition area") is placed directly below the tip of the focused ion beam column (step 620). Next, a deposition precursor gas may be injected into the chamber 110 at a location proximate to the deposition area by, for example, a gas injection system having a gas nozzle 300 according to the present disclosure (step 630).

[0058] During step 630, molecules of the deposition precursor gas adhere to the sample surface according to the adhesion coefficient of the precursor gas. When the gas is delivered to the deposition area, a charged particle beam (e.g., an ion beam) can be generated (step 640), and the charged particle beam is focused and scanned over an area of ​​interest on the sample (step 650). The charged particle beam can be focused by a focusing lens and scanned over an area of ​​the substrate with one or more deflection lenses (not shown). As described above, the cascade of charged particles from beam 125 can activate molecules of the deposition gas that adhere to the sample in the deposition area, thereby causing material to be deposited on the sample, which is localized in the area of ​​the sample over which the ion beam is scanned. For example, the charged particle beam can dissociate the precursor gas, decomposing the gas into volatile and non-volatile components, wherein the non-volatile components remain on the sample surface as deposition material. While embodiments may be used to deposit many different types of materials and are not limited to use with any particular deposition precursor gas, as a specific example, the deposition precursor gas may be tungsten hexacarbonyl (W(CO)6), which may be dissociated by a charged particle beam, leaving a layer of tungsten material deposited within a localized deposition area on the sample.

[0059] In actual implementations, steps 640 and 650 may occur substantially simultaneously and very quickly, and step 630 may be maintained (ie, deposition gas may continue to be introduced into the chamber) while steps 650 and 660 are being performed.

[0060] Once the material from the precursor gas is deposited in the first deposition, if there are additional areas on the sample to deposit material (step 660), the sample can be moved via the substrate support to position the next or subsequent deposition area below the tip of the charged particle column (block 620). If not, the deposition process is complete and the sample can be transferred out of the system 100 or otherwise processed (step 670).

[0061] Additional Implementations

[0062] For the purpose of explanation, the foregoing description uses specific nomenclature to provide a comprehensive understanding of the described embodiments. However, it is apparent to those skilled in the art that specific details are not required to practice the described embodiments. Therefore, the foregoing description of the specific embodiments described herein is presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. For example, although the above embodiments describe the focused ion column as part of a tool having a single charged particle column, in some embodiments, the focused ion beam column may be positioned within a SEM-FIB tool having both a scanning electron microscope column and a focused ion beam column.

[0063] In addition, although different embodiments of the present disclosure are disclosed above, the specific details of a particular embodiment may be combined in any suitable manner without departing from the spirit and scope of the embodiments of the present disclosure. In addition, it will be apparent to those skilled in the art that many modifications and variations are possible in view of the above teachings. Therefore, it should be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the embodiments of the present disclosure.

[0064] Furthermore, any reference to a method in the above specification shall apply, with appropriate modifications, to a system capable of executing the method, and shall apply, with appropriate modifications, to a computer program product storing instructions which, once executed, will result in the execution of the method. Similarly, any reference to a system in the above specification shall apply, with appropriate modifications, to a method executable by the system, and shall apply, with appropriate modifications, to a computer program product storing instructions executable by the system; and any reference to a computer program product in the specification shall apply, with appropriate modifications, to a method executable when the instructions stored in the computer program product are executed, and shall apply, with appropriate modifications, to a system configured to execute the instructions stored in the computer program product.

[0065] Furthermore, while the illustrated embodiments of the present disclosure can be implemented to a large extent using electronic components and circuits known to those skilled in the art, these details will not be explained to a greater extent than is necessary as shown above in order to understand and appreciate the basic concepts of the present disclosure and in order not to obscure or distract from the teachings of the present disclosure.

Claims

1. A gas injection nozzle comprising an elongated gas conduit, the elongated gas conduit comprising: a first gas conduit section configured to be coupled to a gas reservoir; a second gas conduit section fluidly coupled to the first gas conduit section and defining a downward curve of the elongated gas conduit; a third gas conduit section defining an upward curve of the elongated gas conduit, the third gas conduit section extending to a sealed end and disposed in a mirror image relationship with at least a portion of the second gas conduit; and A central gas duct section coupled between the second gas duct section and the third gas duct section, the central gas duct section having a first hole formed in the upper surface of the central gas duct and a second hole formed in the lower surface of the central gas duct directly opposite to the first hole and larger than the first hole, wherein the elongated gas duct has an inner diameter along its length that includes at least the second gas duct section, the third gas duct section and a portion of the central gas duct section, and wherein the central gas duct section includes a substantially horizontal portion extending on each side of the first hole and the second hole a distance at least twice the inner diameter of the gas duct.

2. The gas injection nozzle of claim 1, wherein the diameter of the second hole is at least twice as large as the diameter of the first hole.

3. The gas injection nozzle of claim 1, wherein the substantially horizontal portion of the central gas conduit extends a distance of at least three times the inner diameter of the gas conduit on each side of the first and second holes.

4. The gas injection nozzle of claim 1, wherein the elongated gas conduit comprises stainless steel.

5. The gas injection nozzle of claim 1, wherein an inner diameter of the elongated gas conduit is substantially constant throughout the length of the elongated gas conduit.

6. A gas injection nozzle as claimed in any preceding claim, wherein the inner diameter of the elongate gas conduit is between 1500 and 300 microns.

7. The gas injection nozzle of claim 1, wherein the inner diameter of the elongated gas conduit is between 1000 and 600 microns.

8. A system for depositing a material on a sample in a localized region of the sample, the system comprising: Vacuum chamber; a sample support configured to retain a sample within the vacuum chamber during a sample evaluation procedure; a charged particle beam column configured to direct a charged particle beam into the vacuum chamber toward the sample so that the charged particle beam collides with the sample in a deposition region; a gas injection system configured to deliver a process gas to the deposition area of ​​the sample, the gas injection system comprising an elongated gas conduit, the elongated gas conduit comprising: a first gas conduit section configured to be coupled to a gas reservoir; a second gas conduit section fluidly coupled to the first gas conduit section and defining a downward curve of the elongated gas conduit; a third gas conduit section defining an upward curve of the elongated gas conduit, the third gas conduit section extending to a sealed end and disposed in a mirror image relationship with at least a portion of the second gas conduit; and A central gas duct section coupled between the second gas duct section and the third gas duct section, the central gas duct section having a first hole formed in the upper surface of the central gas duct and a second hole formed in the lower surface of the central gas duct directly opposite to the first hole and larger than the first hole, wherein the elongated gas duct has an inner diameter along its length that includes at least the second gas duct section, the third gas duct section and a portion of the central gas duct section, and wherein the central gas duct section includes a substantially horizontal portion extending on each side of the first hole and the second hole a distance at least twice the inner diameter of the gas duct.

9. The system of claim 8, wherein the charged particle beam column is a focused ion beam column and the charged particle beam is a focused ion beam.

10. The system of claim 8, wherein a diameter of the second hole is at least twice as large as a diameter of the first hole.

11. The system of claim 8, wherein the substantially horizontal portion of the central gas conduit extends a distance of at least three times the inner diameter of the gas conduit on each side of the first and second apertures.

12. The system of claim 8, wherein the elongated gas conduit comprises stainless steel.

13. The system of any one of claims 8 to 12, wherein the inner diameter of the elongate gas conduit is between 1500 and 300 microns.

14. A method for depositing material on a sample in a deposition region of the sample using a charged particle beam column, the method comprising the steps of: positioning the sample within the vacuum chamber so that the deposition region is under the field of view of the charged particle beam column; injecting a deposition precursor gas into the vacuum chamber at a location adjacent to the deposition region using a gas injection system including an elongated gas conduit; generating a charged particle beam with the charged particle beam column and focusing the particle beam within the deposition region of the sample; and scanning the focused particle beam over the deposition region of the sample to activate molecules of the deposition gas that have adhered to the surface of the sample in the deposition region and deposit material on the sample in the deposition region, wherein the elongated gas conduit comprises: a first gas conduit section configured to be coupled to a gas reservoir; a second gas conduit section fluidly coupled to the first gas conduit section and defining a downward curve of the elongated gas conduit; a third gas conduit section defining an upward curve of the elongated gas conduit, the third gas conduit section extending to a sealed end and disposed in a mirror image relationship with at least a portion of the second gas conduit; and A central gas duct section coupled between the second gas duct section and the third gas duct section, the central gas duct section having a first hole formed in the upper surface of the central gas duct and a second hole formed in the lower surface of the central gas duct directly opposite to the first hole and larger than the first hole, wherein the elongated gas duct has an inner diameter along its length that includes at least the second gas duct section, the third gas duct section and a portion of the central gas duct section, and wherein the central gas duct section includes a substantially horizontal portion extending on each side of the first hole and the second hole a distance at least twice the inner diameter of the gas duct.

15. The method of claim 14, wherein the charged particle beam column is a focused ion beam column and the charged particle beam is a focused ion beam.

16. The method of claim 14, wherein a diameter of the second hole is at least twice as large as a diameter of the first hole.

17. The method of claim 14, wherein an inner diameter of the elongated gas conduit is substantially constant throughout the length of the elongated gas conduit.

18. The method of claim 14, wherein the inner diameter of the elongated gas conduit is between 1500 and 300 microns.

19. The method of claim 14, wherein the sample comprises a semiconductor wafer.

20. The method of any one of claims 14 to 19, wherein the substantially horizontal portion of the central gas conduit extends a distance of at least three times the inner diameter of the gas conduit on each side of the first and second holes.

Images