KR20050012738A - Methods and apparatus for monitoring deposition quality during conformable contact mask plating operations - Google Patents

Abstract

Electrochemical fabrication (e.g., EFAB) processes and apparatus providing monitoring of at least one electrical parameter (e.g., voltage) during selective deposition, which aids in determining the quality of the deposition made using the monitored parameters. To start. If the monitored parameters indicate a problem with deposition, various modifications can be made to successfully complete the structure.

Description

METHODS AND APPARATUS FOR MONITORING DEPOSITION QUALITY DURING CONFORMABLE CONTACT MASK PLATING OPERATIONS}

<Related application>

This invention claims the priority of US Patent Provisional Application No. 60 / 379,132, filed May 7, 2002, the contents of which are incorporated herein by reference.

<Government Support>

Some embodiments of some aspects of the invention have been prepared by government support of Grant No. DABT63-97-C-051 awarded by the US Department of Defense Advanced Research Projects Agency (DARPA). This government may have certain rights.

The technique of forming three-dimensional structures (parts, components, devices, etc.) from a plurality of adhesion layers has been invented by Adam L. Cohen and is known as electrochemical manufacture. This is currently based in MEMGen, California Available under the name EFAB ^{™ from} the Corporation of Burbank. This technology is disclosed in US Pat. No. 6,027,630, issued February 22, 2000. This electrochemical deposition technique enables selective deposition of materials using a unique masking technique that involves the use of a mask comprising a conformable material patterned on a support independent from the substrate to be plated on the substrate. Become. When attempting to perform electrodeposition using a mask, the conformable portion of the mask is in contact with the substrate while the plating solution is present such that contact between the conformable portion of the mask and the substrate prevents deposition at a selected location. do. For convenience, such masks are generally referred to as conformable contact masks, and masking techniques are generally referred to as conformable contact mask plating processes. In more detail, MEMGen According to the term of the Corporation of Burbank, this mask is known as INSTANT MASKS ^™ and the process is known as INSTANT MASKING ^™ or INSTANT MASK ^™ plating. Selective deposition using conformable contact mask plating may be used to form a single layer of material or to form a multilayer structure. The teachings of the '630 patent publication are all incorporated herein by reference. The above-mentioned patent application, various documents relating to conformable contact mask plating (ie, INSTANT MASKING), and electrochemical manufacture are disclosed as follows.

1. A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P. Will, "EFAB: Batch production of functional, fully-dense metal parts with micro-scale features", Proc. 9th Solid Freeform Fabrication, The University of Texas at Austin, P161, Aug. 1998.

2. A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P. Will, "EFAB: Rapid, Low-Cost Desktop Micromachining of High Aspect Ratio True 3-D MEMS", Proc. 12th IEEE Micro Electro Mechanical Systems Workshop, IEEE, p244, Jan 1999.

3. A. Cohen, "3-D Micromachining by Electrochemical Fabrication", Micromachine Devices, March 1999.

4. G. Zhang, A. Cohen, U. Frodis, F. Tseng, F. Mansfel, and P. Will, "EFAB: Rapid Destop Manufacturing of True 3-D Microstructures", Proc. 2nd International Conference on Integrated MicroNanotechnology for Space Applications, The Aerospace Co., Apr. 1999.

5.F. Tseng, U. Frodis, G. Zhang, A. Cohen, F. Mansfeld, and P. Will, "EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures using a Low-Cost Automated Batch Process", 3rd international Workshop on High Aspect Ratio Microstructure Technology (HARMST'99), June 1999.

6. A. Cohen, U. Frodis, F. Tseng, G. Zhang, F. Mansfeld, and P. Will, "EFAB: Low-Cost, Automated Electrochemical Batch Fabrication of Arbitrary 3-D Microstructure", Micromachining and Microfabrication Process Technology, SPIE 1999 Symposium on Micromachining and Microfabrication, September 1999.

7.F. Tseng, G. Zhang, U. Frodis, A. Cohen, F. Mansfeld, and P. Will, "EFAB: High Aspect Ratio, Arbitrary 3-D metal Microstructures using a Low-Cost Automated Batch Process", MEMS Symposium, ASME 1999 International Mechanical Engineering Congress and Exposition, November, 1999.

8. A. Cohen, "Electrochemical Fabrication (EFABTM)", Chapter 19 of the MEMS Handbook, edited by Mohamed Gad-EI-Hak, CRC Press, 2002.

9. "Microfabrication-Rapid Prototyping's Killer Application", pages 1-5 of the Rapid Prototyping Report, CAD / CAM Publishing, Inc., June 1999.

These nine documents are all incorporated herein by reference.

Electrochemical deposition processes can be carried out in a number of different ways, as in the patents and documents mentioned above. In one example, this process involves performing three separate operations as follows during the formation of each layer of the structure to be formed.

1. Selectively deposit at least one material by electrodeposition onto one or more required areas of the substrate.

2. The blanket deposition of the at least one additional material is then carried out by electrodeposition to cover the areas where the additional deposits were previously deposited and the areas of the substrate that were not subjected to any selective deposition previously applied.

3. Finally, planarize the material deposited during the first and second operations to have a desired thickness, including at least one region containing at least one material and at least one region containing at least one additional material. To create a smoothed surface of the first layer.

After formation of the first layer, one or more additional layers may be attached to the smoothed surface of the preceding layer and formed immediately adjacent to the preceding layer. This additional layer can be formed by repeating the first to third operations one or more times, in which the formation of each subsequent layer treats the previously formed layer and the initial substrate as new and thicker substrates.

Once all of the layers have been formed, at least a portion of at least one of the deposited materials is generally removed by an etching process to expose or generate the three-dimensional structure that was to be formed.

A preferred embodiment of performing selective electrodeposition associated with the first operation is by conformable mask plating. In this type of plating, one or more conformable contact (CC) masks are first formed. The CC mask includes a support to which the patterned conformable insulating material is attached or formed. The conformable material for each mask is shaped according to the specific cross section of the material to be plated. At least one CC mask is required for each of the unique cross-sectional patterns to be plated.

The support for the CC mask is typically a plate-like structure formed of a metal in which the material to be plated is dissolved and optionally electroplated. In this typical manner, the support functions as an anode in the electroplating process. Alternatively, the support may be a perforated material to which the deposition material is delivered during the electroplating operation that proceeds from the terminal anode to the deposition surface or may be porous. In either way, the CC mask may share a common support, ie, a pattern of conformable insulating material for plating multiple layers of material may be located in different regions of a single support. If a single support comprises multiple plating patterns, the entire structure may be referred to as a CC mask while the individual plating masks may be referred to as a submask. In the present invention, this distinction will only be made when relevant to the particular case.

In preparation for performing the selective deposition of the first operation, the conformable portion of the CC mask is aligned with the selected portion of the substrate (or on a previously formed layer or on a portion of the previously deposited layer) on which the deposition takes place. And pressurized. Pressurization of the CC mask with the substrate occurs in such a way that all openings in the conformable portion of the CC mask contain the plating solution. When the proper potential and / or current is supplied, the conformable material of the CC mask in contact with the substrate serves as a barrier to electroplating while the opening of the CC mask filled with the electroplating solution may be an anode (eg, CC It acts as a path for transferring material from the mask support to the non-contact portion of the substrate (functioning as a cathode during the plating operation).

Examples of CC masks and CC mask plating regions are shown in FIGS. 1A-1C. FIG. 1A shows the side of a CC mask 8 composed of a conformable or deformable (eg, elastomeric) insulator 10 patterned on the anode 12. The anode has two functions. 1A also shows the substrate 6 separated from the mask 8. The first function is to allow the patterned insulator 10 to maintain integrity and alignment because the pattern is complex in topological geometry (eg, with respect to islands of separated insulating material). It is a role as a support material. Another function is as an anode for the electroplating operation. CC mask plating selectively deposits material 22 onto substrate 6 by simply pressing the insulator against the substrate and electroplating the material through apertures 26a and 26b as shown in FIG. 1B. do. After deposition, the CC mask is separated from the substrate, preferably from the substrate 6 without damage, as shown in FIG. 1C. The CC mask plating process is distinguished from the through-mask plating process in that in the through mask plating process, separation of the masking material from the substrate occurs with damage. With through mask plating, CC mask plating deposits the material selectively and simultaneously over the entire layer. The plated region may consist of one or more separate plating regions, which may belong to multiple structures being formed simultaneously or to a single structure being formed. In CC mask plating, individual masks are available in multiple plating operations because they are not intentionally damaged in the removal process.

Other examples of CC masks and CC mask plating are shown in FIGS. 1D-1F. FIG. 1D shows the anode 12 ′ separated from the mask 8 ′ comprising the patterned conformable material 10 ′ and the support 20. 1D also shows the substrate 6 separated from the mask 8 '. 1E shows a mask 8 ′ in contact with the substrate 6. FIG. 1F shows the deposit 22 ′ generated by conducting current from the anode 12 ′ to the substrate 6. 1G shows the deposit 22 ′ on the substrate 6 after separation from the mask 8 ′. In this example, a suitable electrolyte is located between the substrate 6 and the anode 12 ', and the ion flow from one or both of the solution and the anode is conducted through the opening in the mask to the substrate onto which the material is deposited. This kind of mask may be referred to as an anodeless INSTANT MASK ^™ (AIM) or an anodeless conformable contact (ACC) mask.

Unlike through masking plating, by CC mask plating, the CC mask can be formed by completely separating (eg, separating from the three-dimensional (3D) structure to be formed) with the manufacture of the substrate on which the plating will occur. The CC mask can be formed in a variety of ways, for example using a photolithography process. All masks may be created at the same time prior to fabrication of the structure and not during fabrication of the structure. This separation enables a desktop factory that is simple, inexpensive, automated, self-contained, internally clean, and can be installed in virtually any location to produce 3D structures. This allows clean room processes to be performed by a service bureau or the like, such as any desired photolithography.

One example of such an electrochemical manufacturing process is shown in FIGS. 2A-2F. This figure shows that the process includes the deposition of a first material 2 as a sacrificial material and a second material as a structural material. In this example, the CC mask 8 comprises a support 12 formed of a patterned conformable material (eg an elastomeric insulating material) 10 and a deposition material 2. The conformable portion of the CC mask is pressed against the substrate 6 with the plating liquid 14 located in the opening 16 of the conformable material 10. The current passes from the power source 18 through (a) the plating liquid 14 through the support 12, which doubles as an anode and (b) passes through the substrate 6 through the substrate 6, which doubles as a cathode. It becomes 2A shows that current transfer allows material 2 from the plating liquid and material from anode 12 to be selectively transferred to cathode 6 and plated. After electroplating the first plating material 2 onto the substrate 6 using the CC mask 8, the CC mask 8 is removed as shown in FIG. 2B. FIG. 2C shows the second deposition material 4 blanket deposited (ie non-selectively deposited) relative to the remaining portion of the substrate 6 as well as the previously deposited first deposition material 2. Blanket deposition occurs by electroplating from an anode (not shown) composed of a second material to the cathode / substrate 6 using a suitable plating solution (not shown). Thereafter, the entire two material layers are planarized as shown in FIG. 2D to obtain precise thickness and flatness. After repeating this process for all layers, the multilayer structure 20 formed of the second material (ie, structural material) is embedded in the first material 2 as shown in FIG. 2E. The embedded structure, as shown in FIG. 2F, is etched to produce the required device, ie structure 20.

Various components of an exemplary passive electrochemical manufacturing system 32 are shown in FIGS. 3A-3C. System 32 consists of several subsystems 34, 36, 38, and 40. The substrate holding subsystem 34 is shown on top of each of FIGS. 3A-3C and includes several components as follows. That is, (1) carrier 48, (2) metal sub-substrate 6 on which layers are deposited, and (3) substrate 6 up and down relative to carrier 48 according to the driving force from actuator 44. A movable linear slide 42. Subsystem 34 also includes an indicator 46 for measuring the difference in the vertical position of the substrate that can be used to set or determine the layer thickness and / or deposition thickness. Subsystem 34 further includes feet 68 for carrier 48 that can be precisely mounted on subsystem 36.

The CC mask subsystem 36 shown at the bottom of FIG. 3A includes several components as follows. That is, (1) a CC mask (8), (2) a precision X stage, (3) a precision Y stage (56) consisting of a number of CC masks (i.e. submasks) that actually share a common support / anode 12. (4) a frame 72 on which the pit 68 of the subsystem 34 can be mounted, and (5) a tank 58 for containing the electrolyte 16. Subsystems 34 and 36 also include suitable electrical connections (not shown) for connecting to suitable power supplies to drive the CC masking process.

The blanket deposition subsystem 38 is shown at the bottom of FIG. 3B and includes several components as follows. That is, the frame 74 in which (1) the anode 62, (2) the electrolyte tank 64 for holding the plating solution 66, and (3) the pit 68 of the subsystem 34 can be located. It includes. Subsystem 38 also includes suitable electrical connections (not shown) that connect the anode to a suitable power source to drive the blanket deposition process.

Planarization subsystem 40, shown at the bottom of FIG. 3C, includes a lapping plate 52 and associated motion and control system (not shown) to planarize the deposit.

Another method of forming microstructures from electroplated metals (ie, using electrochemical fabrication techniques) is US patent number Henry Guckel, entitled "Formation of Microstructures by Multiple Level Deep X-ray Lithography with Sacrificial Metal layers". 5,190,637. This patent teaches the formation of a metal structure using mask exposure. The first layer of primary metal is electroplated onto the exposed plating base to fill the voids of the photoresist, after which the photoresist is then removed and the secondary metal is electroplated over the first layer and the plating base. The exposed surface of the secondary metal is then machined down to a height that exposes the first metal and extends across the primary and secondary metals to create a flat, uniform surface. Thereafter, the formation of the second layer can begin by applying a photoresist layer to the second layer and repeating the process used to create the first layer. This process is then repeated until the entire structure is formed and the second metal is removed by etching. The photoresist is formed over the plating base or previous layer by casting, and voids are formed in the photoresist by exposure of the photoresist using a mask patterned through X-rays or UV radiation.

There is a need for improved plating quality diagnostics for use in conformable contact mask plating, particularly for use when multiple layers are subsequently deposited to form structures from a plurality of adhesion layers. It is also necessary to minimize time wasting, effort, and metal when the diagnosis indicates or may have occurred a failed deposition or problematic deposition.

Summary of the Invention

One object of certain aspects of the present invention is to provide a contact or attached mask plating or electrochemical manufacturing process or apparatus capable of recognizing the improved quality of an attempted plating operation.

Another object of certain aspects of the present invention is to provide a contact or attached mask plating or electrochemical fabrication process or apparatus that reduces time wasted when a failed deposition occurs or is likely to occur.

Another object of certain aspects of the present invention is to provide a contact or attached mask plating or electrochemical manufacturing process or apparatus that reduces the consumption associated with previous operations when a failed deposition has occurred or is likely to have occurred. will be.

Another object of certain aspects of the present invention is to provide a contact or attached mask plating or electrochemical manufacturing process or apparatus that reduces consumable material resulting from previous operations when a failed deposition has occurred or is likely to have occurred. To provide.

Other objects and advantages of various aspects of the invention will become apparent to those skilled in the art upon reviewing the teachings of the invention. Various aspects of the invention expressly set forth herein or identified from the teachings herein may focus on any one or combination of the above objects, or on any of the above objects. It may not, but may focus on some other aspects identified from the teachings herein. While all of these objects may be relevant in some aspects, it is not intended to focus on all those objects by any one aspect of the present invention.

According to a first aspect of the present invention, an electrochemical fabrication process for creating a three-dimensional structure from a plurality of adhesion layers selectively comprises at least a portion of the layer onto the substrate, which may comprise a material deposited prior to (A). And (B) repeating (A) the selective deposition step a plurality of times, comprising forming a plurality of layers such that successive layers are formed adjacent and attached to previously deposited layers; Repeating the selective deposition step a plurality of times comprises (1) placing a mask on or near the substrate, and (2) when a plating solution is present, depositing the selected deposition material onto the substrate. Conducting current between the anode and the substrate through at least one opening in the mask to form at least a portion of the layer; (3) the mask from the substrate Removing the charge, and monitoring the voltage between the anode and the cathode during formation of the desired layer.

An electrochemical fabrication process for creating a three-dimensional structure from a plurality of adjacent layers comprises the steps of: (A) selectively depositing at least a portion of the layer onto the substrate, which may include a previously deposited material, and (B) (A) repeating the selective deposition step a plurality of times, comprising forming a plurality of layers such that successive layers are formed adjacent and attached to previously deposited layers, and wherein the selective deposition step is performed multiple times The steps of repeating include (1) placing a mask on or near the substrate, and (2) if a plating solution is present, the selected deposition material is deposited onto the substrate to form at least a portion of the layer. Conducting a current between an anode and the substrate through at least one opening in the mask, and (3) removing the mask from the substrate. And, during the formation of a given layer or after the formation of a given layer, the layer is inspected, or if the formation parameters are compared with expected parameter values to determine that the layer is not formed correctly, the material deposited in relation to the layer. At least a portion of is removed and a substitute material is deposited.

According to a third aspect of the invention, a conformable contact masking process for creating a structure comprises (A) a patterned insulating material comprising at least one opening through which deposition may be performed during formation of at least a portion of the layer. Supplying at least one preformed mask comprising; and (B) selectively depositing at least a portion of the layer onto the substrate, wherein the selective deposition step comprises: i) insulating material of the preformed mask; Contacting the substrate, and ii) at least one opening in the mask to direct current between the substrate and the substrate so that, if present, a selected deposition material is deposited onto the substrate to form at least a portion of the layer. Conducting through, and iii) separating the preselected selected mask from the substrate, wherein Monitor the voltage between anode and cathode during formation.

According to a fourth aspect of the present invention, a conformable contact masking process for producing a structure comprises (A) a patterned insulating material comprising at least one opening through which deposition may be performed during formation of at least a portion of the layer. Supplying at least one preformed mask comprising; and (B) selectively depositing at least a portion of the layer onto the substrate, wherein the selective deposition step comprises: i) insulating material of the preformed mask; Contacting the substrate, and ii) at least one opening in the mask to direct current between the substrate and the substrate so that, if present, a selected deposition material is deposited onto the substrate to form at least a portion of the layer. Conducting through and iii) separating the preselected selected mask from the substrate, During the formation of the layer or after the formation of the predetermined layer, the layer is inspected, or if formation parameters are compared with expected parameter values to determine that the layer is not formed correctly, at least a portion of the deposited material in relation to the layer is It is removed and a substitute material is deposited.

According to a fifth aspect of the present invention, an electrochemical manufacturing apparatus for generating a three-dimensional structure from a plurality of adjacent layers comprises: (A) selectively selecting at least a portion of the layer onto the substrate, which may comprise a material deposited previously. Means for forming the continuous layer such that each of the continuous layers is adjacent and attached to a previously deposited layer, and (C) the cathode and anode during selective deposition. Means for monitoring the voltage of the liver; wherein the selective deposition means comprises: (1) means for placing a mask on or near the substrate, and (2) when a plating solution is present, Means for conducting a current between the anode and the substrate through at least one opening in the mask to be deposited onto and form at least a portion of the layer; (3) the substrate Means for removing the mask from the.

According to a sixth aspect of the present invention, an electrochemical manufacturing apparatus for producing a three-dimensional structure from a plurality of adjacent layers comprises: (A) selectively selecting at least a portion of the layer onto the substrate, which may comprise a material deposited previously. Means for forming the continuous layer such that each of the continuous layers is adjacent and attached to a previously deposited layer by repeatedly performing (B) selective deposition; and (C) inspecting or forming the formation parameters. Means for comparing the parameter to an expected parameter value, and (D) means for removing at least a portion of the deposited material in connection with the predetermined layer and depositing a substitute material if it is determined that the layer is not formed correctly; Selective deposition means include (1) means for placing a mask on or near the substrate, and (2) the selected deposition material onto the substrate, if a plating solution is present. Means for conducting a current between the anode and the substrate through at least one opening in the mask to deposit to form at least a portion of the layer, and (3) means to remove the mask from the substrate.

Other aspects of the present invention will be understood by those skilled in the art upon reviewing the teachings herein. Other aspects of the invention may include combinations of the various aspects of the above-described aspects of the invention and / or one or more embodiments. Another aspect of the invention may include an apparatus that may be used to implement one or more of the method aspects of the invention described above. These other aspects of the invention may provide other configurations, structures, functional relationships, and processes not specified above, as well as provide various combinations of the above aspects.

Embodiments of the present invention relate to the field of electrochemical manufacturing and related electrochemical material deposition, in some embodiments depending upon the cross-sectional configuration required, and in some embodiments, multilayer 3 from a plurality of adhesion layers of deposition material. Depending on the construction of the dimensional structure, masks for selective patterning operations (eg, selective electrochemical deposition operations) are used.

1A-1C schematically illustrate aspects of various stages of a CC mask plating process, while FIGS. 1D-1G schematically illustrate aspects of various stages of a CC mask plating process using different types of CC masks.

2A-2F schematically illustrate aspects of various stages of an electrochemical manufacturing process when applied to the formation of a particular structure in which a sacrificial material is selectively deposited while the structural material is blanket deposited.

3A-3C schematically illustrate aspects of various subassembly examples that may be used to manually implement the electrochemical manufacturing method shown in FIGS. 2A-2F.

4A-4I schematically illustrate the formation of a first layer of a structure using attachment mask plating in which blanket deposition of a second material overlaps an opening between the deposition location of the first material and the first material itself.

FIG. 5 shows anode and cathode polarization curves combined for specific copper baths operating at 20 ° C. and 50 ° C. FIG.

6A-6C show the cell voltage versus plating time for the first plating bath when three different deposition results occurred.

7A and 7B show the cell voltage versus plating time for the first plating bath when two different deposition results occurred.

8 is a diagram showing copper deposition in which spikes are generated.

1A-1G, 2A-2G, and 3A-3C show various features of one form of known electrochemical preparation. Other electrochemical manufacturing techniques are disclosed in the aforementioned '630 patents, several publications already included, various other patents and patent applications incorporated by reference, and are described in such publications, patents, and patent applications, or Many other techniques can be derived by a combination of various other approaches that can be identified or known to one skilled in the art. All of these techniques can be combined with the techniques of various embodiments of various aspects of the present invention to yield improved embodiments. Other embodiments can be derived from combinations of the various embodiments explicitly described herein.

4A-4I illustrate the various stages of monolayer formation in a multilayer fabrication process in which the deposition of the metal will form part of the layer, as well as in the openings of the first metal, in which the second metal is deposited on the first metal. In FIG. 4A, a side of the substrate 82 is shown, and a patternable photoresist 84 is cast onto that side as shown in FIG. 4B. In FIG. 4C, a resist pattern resulting from curing, exposure, and development of the resist is shown. Patterning of the photoresist 84 results in openings or apertures 92a-92c extending from the surface 86 of the photoresist to the surface 88 of the substrate 82 through the thickness of the photoresist. In FIG. 4D, metal 94 (eg nickel) is electroplated into openings 92a through 92c. In FIG. 4E, the photoresist is removed from the substrate (ie, chemically stripped) to expose an area of the substrate 82 that is not covered with the first metal 94. In FIG. 4F, the second metal 96 (eg, silver) is blank blanked over the entire exposed portion of the substrate 82 (conductive) and against the top of the first metal 94 (also conductive). It is shown as plated. 4G shows the complete first layer of the structure resulting from planarizing the first and second metals until reaching a height that exposes the first metal and sets the thickness for the first layer. In FIG. 4H, the process steps shown in FIGS. 4B-4G are repeated several times to form a multilayer structure, where each layer consists of two materials. In most applications, one of these materials is removed as shown in FIG. 4I to obtain the required 3-D structure 98 (eg, component or device).

Although the above embodiment focuses on conformable contact masks and masking operations, various embodiments, alternatives, and techniques described herein, may be used to provide proximity masks and masking operations (ie, not contacted to a substrate). Using a mask that at least partially and selectively shields the substrate by proximate the mask), non-conformable masks and masking operations (ie, masks and operations based on masks whose contact faces are not highly conformable), and attachment masks And masking operations (i.e., masks and operations using masks attached to the substrate where selective deposition or etching will occur, as opposed to just being contacted to the substrate).

The basic standard plating configuration (ie, non-CC mask plating configuration) includes an anode and a cathode immersed in the plating bath. The distance between the anode and the cathode is at least 1 mm. The power supply provides a pre-set current through the plating cell such that the anode metal is generally dissolved in the plating bath and the metal ions in the plating bath are reduced at the cathode to become a metal deposit. Depending on the various parameters including the composition of the plating bath, the plating bath is generally operated at a constant temperature in the range of 20 ° C to 60 ° C. The plating bath is mechanically agitated or pneumatically compressed to ensure that a fresh plating solution is transferred to the cathode and that the result of the electrochemical reaction is removed from the electrode into the bulk solution.

Through mask plating is a selective plating process because the substrate (cathode) is patterned by a non-conductive thin film material (eg, patterned photoresist). Otherwise, the plating configuration is approximately the same as that of the standard plating process as described above. As such, in this specification, optional forms of standard plating can be considered by through mask plating.

CC mask plating differs from general through mask plating in many ways. In one form of CC mask plating, the plating bath is trapped in a hermetic volume defined by the substrate, sidewalls of the conformable material, and the anode. Examples of such closed volumes 26a, 26b are shown in FIG. 1B. Another form of CC mask plating may include using a porous support and a terminal anode. In another form of CC mask plating, the barrier presented by the support of the CC mask allows at least some ion exchange, but can sufficiently prevent some component exchange of the plating solution so that the plating solution in the deposition area is still substantially free from the bulk solution. Can be considered to be separated. By this trapping, mass exchange between the solution volume and the bulk solution in the plating zone occurs little or rarely, such that a fresh solution with an appropriate adhesive may or may not be supplied to the microspace and the reactants are removed. May be removed or rarely removed.

Preferred forms of CC mask plating include a hermetic volume in which at least one of the at least one dimensions of the plating capacity is tens of microns (eg, 20 μm to 100 μm) or less. As such, this form of CC mask plating can be considered a microbath plating process (ie, micro-CC mask plating).

For micro-CC mask plating, the preferred separation between anode and cathode is currently between about 20 μm and about 100 μm, more preferably between about 40 μm and 80 μm. As such, regardless of the size of the region to be deposited, these preferred embodiments can be considered as a micro-CC mask plating process. Of course, thinner separation distances (eg 10 μm or less) and thicker separation distances (300 μm or more) are also possible. Because of this close spacing between the anode and the cathode, the deposition process at the cathode and the dissolution process at the anode have large interactions, unlike standard plating.

Agitation of the plating bath is possible as is common in standard plating processes, but is essential for electroplating production, potentially due to the high interaction between the anode and the cathode and due to the increased likelihood of shorting when agitation is used. Not. The short indicates the portion of the deposition height that connects the cathode and the anode before the elapse of the required deposition time, in which case the current is deposited only as opposed to the case where it is primarily flowing through the plating bath as intended to prevent continuous deposition. It only flows through the conductive material.

The use of pyrophophate baths at high temperatures (ie, about 43 ° C. to 45 ° C.) is recommended in standard plating processes, but the high attack potential at the interface between the CC mask support and the conformable material and the associated CC mask Shortening of life is undesirable in current forms of micro-CC mask plating.

CC mask plating has unique features, and the prior art associated with standard plating processes may be an obstacle rather than helping to develop commercial CC mask plating processes and systems. The following table provides a detailed comparison of the two forms of standard plating (ie, non-selective plating and through mask plating) and various aspects of micro-CC mask plating.

Characteristic Standard plating Micro-CC Mask Plating Common plating Through Mask Plating Patterned cathode none has exist has exist Separation between anode and cathode Macro Scale Macro Scale Micro Scale <~ 80 μm Sealed Micro Jaw Plating none none has exist Crude stirring Useful and easy Useful and easy Yes, but I have a problem Bath heating Useful and easy Useful and easy Yes, but I have a problem New bath supplied to the electrode has exist has exist none Material removed from the electrode has exist has exist none Cathode: anode area ratio Variable Variable 1: 1 Plating time No limit No limit Limited Interaction between cathode and anode Insignificant Insignificant Equivalency

It has been found that the cell voltage monitored during the CC mask plating process can be correlated to various aspects of the quality at which deposition is being performed. This cell voltage information can be used alone or in combination with visual inspection to determine the acceptability of any deposit deposited or deposited. If the deposit is determined to be acceptable, the process may then continue with the deposition or other operation. On the other hand, if it is determined that the deposit is unacceptable, the process may be bypassed to remove some or all of the unacceptable deposit, and then may attempt to redeposit one or more times until an acceptable deposition has been performed and then the process itself You can continue along the usual course.

The cell voltage is the potential between the anode and the cathode at a given current density. This depends on the potential at the two electrodes, the size and spacing of the anode and cathode, the applied current, and the resistance of the bath. The cell voltage can be expressed as follows.

V _cell = V _anode + V _bath + V _cathode

Where V _anode and V _cathode are the voltage drops at the anode and cathode due to the polarization of the electrodes when passing current through the _bath , and V _bath is the voltage drop in the _{bath when} the current flows through the _bath between the anode and the cathode. . V _bath can be calculated as follows.

V _bath = IR

Where I is the total current and R is the effective contact resistance of the bath. Because the gap between the anode and the cathode (about 25 μm to 100 μm) is typically very small, and because the specific conductivity of the various plating baths known is 10 ⁻¹ units, the voltage drop for a 20 mA / cm ² current can range from tens of millivolts to It has units of several millivolts. As such, the voltage drop across the normal bath can be ignored when compared to the voltage drop associated with the _anode and V _cathode . Using the polarization curves for the V _anode and V _cathode , we can estimate the appropriate value of the cell voltage. The anode and cathode polarization curves measured in the plating bath indicate the potential of the anode and cathode at different current densities. FIG. 5 shows a combined example of node and cathode polarization curves measured in a copper plating bath (ie Cu-P bath by Technic of Cranston RI) at 20 ° C. and 50 ° C. without stirring. Both anode and cathode potentials shown in FIG. 5 were measured for saturated calomel electrodes and current densities. In this figure, the cell voltage at 20 mA / cm ² can be determined between 1.9 and 1.3 V, respectively, for a bath temperature in the range of 20 ° C. to 50 ° C.

It has been determined that cell voltage measurements during plating can provide information regarding several different plating conditions / results. In a preferred embodiment, the current supplied between the anode and the cathode is such that the average current density at the cathode is equal to the value required due to the known open area of the conformal contact mask (i.e. the total current supplied based on the plating area). If the plating operation functions properly, a predictable voltage can be obtained.

It is anticipated that different characteristic voltage curves may occur during plating by different plating baths, operating conditions, power supply control parameters, and plating guns. It is also contemplated that a person skilled in the art can perform an empirical test to correlate acceptable or unacceptable plating to voltage values or curves (ie, profiles over time) for different operating conditions. This correlation or curve can be used to define acceptable criteria that can be used to determine the acceptability of subsequent plating operations.

6A and 7A show typical cell voltage curves for 4 minutes plating time for two different copper pyrophosphate plating baths operated at room temperature. FIG. 6A is based on a Cu-P plating bath while FIG. 7A is based on a UNICHROME plating bath with optimal formulation as suggested by Atotech. This curve was recorded on a strip chart recorder during the actual plating. Under the conditions used, the general plating process exhibits a smooth and stable cell voltage curve over time. In addition, the cell voltage remained substantially constant (ie, kept within a narrow range).

An example of a plating process failure is shown in FIG. 6C where large cell voltage variations and cell voltage instability are caused by improper plating operations occurring and the coating applied (1) requiring thickness, (2) One or more deficiencies in uniformity, (3) bonding to the substrate as needed, and / or (4) structural properties of some other as needed.

Short circuits may arise from variations in deposition thickness. An SEM image of the copper layer produced by conformal contact mask plating with a 30 minute deposition time is shown in FIG. 8. Many spikes 102 can be seen around the edge of the copper deposit 104. Large spikes 102 are higher than the rest of the deposit. If the height of one or more spikes extends to contact the anode, a short circuit occurs and the plating process cannot proceed because current is conducted through the lower resistive metal bath rather than the electrolyte. If a short circuit occurs, the cell voltage immediately drops to zero. FIG. 6B shows a plot of cell voltage versus time for which a short occurred less than expected plating time.

Flash deposits are unnecessary additional deposits that extend beyond the intended masking area. In other words, because the actual cathode area is larger than expected and the overall current is constant, the actual current density at the cathode is smaller than expected. From the polarization curve of FIG. 5, it can be seen that as the current density decreases, the cathode potential becomes more positive, thus reducing the overall cell voltage. Thus, if the monitored cell voltage is lower than expected, instantaneous deposits may occur. 7A shows a typical cell voltage, while the cell voltage of FIG. 7B is lower than a normal value.

For each deposition by conformable contact masking, the deposition process can be monitored when a problem is recognized during or after completion of the deposition. Based on an analysis that compares the resulting voltage curve to an expected curve or to some acceptable or unacceptable criteria, whether the formation process should continue on schedule, whether the formation process should be canceled, or some form of Decisions can be made on whether to take corrective or corrective actions. Problem detection can occur by automated system recognition, or a combination thereof, by operator review and analysis of one or more monitored electrical signals (eg, voltages). Depending on the level of automation of the system and the expected severity of the problem, the operator may perform corrective actions under automated system control or manually, which may include a number of different actions as follows.

(1) If present, visual or other secondary inspections may be performed to confirm that a problem has occurred or to determine the severity of the problem, to assist in making a decision as to the most appropriate form of additional corrective action to take.

(2) If offending is still in progress even upon problem recognition, i. Cancel the deposition or ii. It can only last for a while.

(3) One or more additional depositions may occur (eg, to ensure complete lateral support of the deposited structure).

(4) Trimming processes (eg, mechanical lapping or planarization by CMP) may be implemented to remove all or part of the undesirable deposits.

(5) Partial or complete redeposition of undesirable patterns can be performed.

i. The same mask may be used in more than one subsequent attempt, or ii. Other masks may be used in one or more subsequent devices.

(6) If optimal redeposition is not achieved within a given number of attempts, the automated system can be programmed to interrupt the formation process, ongoing operator intervention, or to continue the formation process while attempting to correct the steps and occurrences that have been attempted. Leave the appropriate log.

Various embodiments of the invention may be implemented using a single disallowable criterion (eg, paragraph recognition) or using multiple disallowable criteria. The same modification process may be performed according to each disallowed criterion used, or different modification actions may be implemented by different disallowable criteria. In some embodiments, the corrective action may include each of the operations (1) to (6) as described above. In other embodiments, only a subset of operations (1) through (6) may be used and, if necessary, for example, (2) then (4), (4) then (5), and (5). Then (6) can be performed. Each time action 6 occurs if a certain number of attempts have not been made, the corrective action may be different. In some embodiments, if a problem associated with a given layer is considered to be a result of a problem in a previous layer, or if the modification steps made in the current layer negatively affected one or more previous layers, one or more depositions associated with the current layer may be In addition to being trimmed, the material may also be trimmed from one or more previous layers. Redeposition of the material to the current layer and any previous layer of material removed may be performed. In some embodiments, the trimming operation may include an anode etch in addition to or in addition to other trimming processes. Various other problem recognition possibilities and corrective action possibilities, and combinations thereof, will be apparent to those skilled in the art by the teachings herein.

There are various other embodiments of the present invention. Some of these embodiments may be based on combinations of the teachings herein with the various teachings incorporated herein by reference. Some embodiments may not use any blanket deposition process and / or may not use a planarization process. Some embodiments may include selective deposition of a plurality of different materials on a single layer or on different layers. Some embodiments may use a blanket deposition process rather than an electrodeposition process. Some embodiments may utilize an optional deposition process on some layers that is neither a conformable contact masking process nor an electroplating process. Some embodiments may use nonconformable masks, proximity masks, and / or attachment masks for selective patterning operations. Some embodiments may use nickel as a structural material while other embodiments may be gold, silver, or any other electroplatable that may be separated from selected sacrificial materials (eg, copper and / or some other sacrificial material). Different materials such as materials can be used. Some embodiments may use copper as a structural material with or without sacrificial material. Some embodiments may remove the sacrificial material while others may not. In some embodiments, the anode can be different from the conformable contact mask support, which can be a porous structure or other penetrating structure. Some embodiments may use multiple conformable contact masks with different patterns to deposit different selective patterns of material on different layers and / or on different portions of a single layer. In some embodiments, the deposition depth is determined when deposition occurs in such a way that sealing between the conformable portion of the CC mask and the substrate can shift from the face of the conformable material to the inner edge of the conformable material, It can be improved by leaving the conformable contact mask away from the substrate. In some embodiments, monitoring of electrical parameters may not be performed, or may not lead to the conclusion of removal and redeposition of material by the monitored parameters, but instead a manual or automated visual inspection of the decision for such deposition. This can be done by.

In accordance with the teachings herein, many further embodiments, and alternatives, in the design and use of the invention will be apparent to those skilled in the art. As such, the invention is not limited to the specific exemplary embodiments, alternatives, and uses described above, but only by the claims.

Claims (26)

In the electrochemical manufacturing process for generating a three-dimensional structure from a plurality of adjacent layers, (A) selectively depositing at least a portion of the layer onto the substrate, which may include a previously deposited material; (B) repeating (A) the selective deposition step a plurality of times, forming a plurality of layers such that successive layers are formed adjacent and attached to previously deposited layers Including, Repeating the selective deposition step a plurality of times, (1) placing the mask on or near the substrate; (2) conducting a current between an anode and the substrate through at least one opening in the mask such that, if present, a selected deposition material is deposited onto the substrate to form at least a portion of the layer; (3) removing the mask from the substrate Including, During the formation of the desired layer, monitoring the voltage between the anode and the cathode. The method of claim 1, Wherein the plurality of layers comprises at least one structural material and at least one sacrificial material. The method of claim 1, (C) further supplying a plurality of pre-configured masks, Each mask includes a patterned insulating material comprising at least one opening through which deposition may be performed during formation of at least a portion of the layer, and a support supporting the patterned insulating material, Positioning the mask on or near the substrate comprises contacting the substrate with an insulating material of a preselected selected mask. The method of claim 1, Positioning the mask on or near the substrate comprises forming and attaching a patterned mask to the substrate. The method of claim 1, Based at least in part on the monitored voltage, a determination is made that deposition for a given layer is unacceptable, The process, (A) removing at least a portion of the material deposited in association with the predetermined layer, (B) repeating the deposition for at least a portion of the given layer Electrochemical manufacturing process characterized in that it further comprises. The method of claim 5, And performing said determination based on visual inspection of the deposition results for a given layer. The method of claim 5, And wherein said measured voltage profile for at least one layer represents flash. The method of claim 5, Comparing the measured voltage profile with an expected voltage profile may indicate flash occurrence. The method of claim 5, And wherein said measured voltage profile for at least one layer exhibits a short circuit. The method of claim 5, Comparing the measured voltage profile with an expected voltage profile may indicate a short circuit occurrence. In the electrochemical manufacturing process for generating a three-dimensional structure from a plurality of adjacent layers, (A) selectively depositing at least a portion of the layer onto the substrate, which may include a previously deposited material; (B) repeating (A) the selective deposition step a plurality of times, forming a plurality of layers such that successive layers are formed adjacent and attached to previously deposited layers Including, Repeating the selective deposition step a plurality of times, (1) placing the mask on or near the substrate; (2) conducting a current between an anode and the substrate through at least one opening in the mask such that, if present, a selected deposition material is deposited onto the substrate to form at least a portion of the layer; (3) removing the mask from the substrate Including, During the formation of a given layer or after the formation of a given layer, the layer is inspected, or if formation parameters are compared with expected parameter values to determine that the layer is not formed correctly, at least of the deposited material in relation to the layer. An electrochemical manufacturing process, characterized in that part is removed and a substitute material is deposited. The method of claim 11, Wherein the plurality of layers comprises at least one structural material and at least one sacrificial material. The method of claim 11, (C) further supplying a plurality of pre-configured masks, Each mask includes a patterned insulating material comprising at least one opening through which deposition may be performed during formation of at least a portion of the layer, and a support supporting the patterned insulating material, Positioning the mask on or near the substrate comprises contacting the substrate with an insulating material of a preselected selected mask. The method of claim 11, Wherein the inspection comprises monitoring the electrical properties of the selective deposition step. The method of claim 14, The electrical property comprises a voltage between the anode and the cathode during conduction of the current. The method of claim 14, The monitoring occurs during the formation of a plurality of substantially all layers. The method of claim 15, The monitored voltage for each layer comprises a measured voltage profile for deposition time in each layer. The method of claim 17, At least two points of the voltage profile measured for a given layer are used for comparison with the expected voltage profile, Based at least in part on the comparison result to determine whether the deposition was acceptable. The method of claim 11, Each formation of the plurality of layers comprises at least one blanket deposition as well as the selective deposition, And wherein the selective deposition material for a given layer is different from the material deposited by blanket deposition. The method of claim 11, Wherein the plurality of selective depositions comprises deposition of a plurality of different materials. The method of claim 11, At least a portion of one layer is formed by a non-electroplating deposition process. The method of claim 11, The plurality of depositions occur during each formation of the plurality of layers, At least one of the depositions on each of the plurality of layers deposits copper, Wherein at least one of the remaining depositions deposits nickel on the plurality of layers. The method of claim 11, Wherein said selective deposition for each of the plurality of layers comprises at least two selective depositions. The method of claim 11, The plurality of layers is formed by depositing at least one structural material using at least one deposition and depositing at least one sacrificial material using at least one other deposition. The method of claim 21, At least a portion of the at least one sacrificial material is removed after forming a plurality of layers to produce a three-dimensional structure of at least one structural material. In a conformable contact masking process for creating a structure, (A) supplying at least one preformed mask comprising a patterned insulating material comprising at least one opening through which deposition may be performed during formation of at least a portion of the layer; (B) selectively depositing at least a portion of the layer onto the substrate Including, The selective deposition step, i) contacting said substrate with an insulating material of said preformed mask, ii) conducting a current between an anode and the substrate through at least one opening in the mask so that the selected deposition material is deposited onto the substrate to form at least a portion of the layer, when a plating solution is present; iii) separating the preselected selected mask from the substrate, During the formation of a given layer or after the formation of a given layer, the layer is inspected, or if formation parameters are compared with expected parameter values to determine that the layer is not formed correctly, at least of the deposited material in relation to the layer. A conformable contact masking process, wherein a portion is removed and a replacement material is deposited.