JP2007535384A - Method for fabricating complex blade shapes on silicon wafers and method for strengthening blade shapes - Google Patents

Abstract

  The ophthalmic surgical blade is made from a monocrystalline or polycrystalline material, preferably in the form of a wafer, from a monocrystalline or polycrystalline material. This method involves preparing a single crystal or polycrystalline wafer by attaching a single crystal or polycrystalline wafer and etching a groove in the wafer using one of several processes. Including. Methods for machining the grooves forming the beveled blade surface include diamond blade saws, laser systems, ultrasonic machines, hot forging presses and routers. Other methods include wet etching (isotropic and anisotropic) and dry etching (isotropic and anisotropic, including reactive ion etching), and combinations of these etching steps. The wafers are then placed in an etchant that uniformly and isotropically etches the wafers, resulting in a uniform removal of the crystalline or polycrystalline material layer, resulting in a single, double or multiple Create a bevel blade. Almost any angle can be machined into the wafer, and this machined angle remains after etching. The resulting radius of the cutting edge is 5 to 500 nm, which is the same diameter as a diamond edge blade but is manufactured at a fraction of the cost. The radius range may be from 30 to 60 nm, and in a particular embodiment is about 40 nm. The blade profile has, for example, an angle of about 60 °. The ophthalmic surgical blade is enabled for cataract surgery, refractive surgery, and microsurgery, biological, non-medical, non-biological applications. Also, surgical and non-surgical blades and machine elements manufactured as described herein exhibit a substantially smoother surface property than metal blades.

Description

  This application consists of five US patent provisional applications, US Provisional Application No. 60 / 362,999, entitled “System and Method for the Manufacture of Surgical Blades” filed on March 11, 2002, 2002. US Provisional Application No. 60 / 430,322 entitled “System and Method for the Manufacture of Surgical Blades” filed on Dec. 3, and “System and Method for Creating Linear and Application” on Sep. 17, 2003. US Provisional Application No. 60 / 503,458 entitled “Non-Linear Trenches in Silicon and Other Crystalline Materials with a Router”, “Silicon Blades for Surgical and Non-Surgical Use” filed on September 17, 2003. US Provisional Patent Application No. 60 / 503,459 and “Silicon Surgical Blades and Method of Manufacture” filed April 30, 2004 Application No. 60 / 566,397, and US Patent Non-Provisional Application No. 10 / 383,573, entitled “System and Method for the Manufacture of Surgical Blades” filed March 10, 2003 The contents of all of the preceding provisional and non-provisional applications mentioned above, including the contents related to

  The present invention relates to ophthalmology and other types of surgical and non-surgical blades and mechanical devices. More particularly, the present invention relates to ophthalmic, ultrasurgical and non-surgical blades and mechanical devices made from single crystal silicon and other single crystal or polycrystalline materials, as well as the mechanical devices, surgical procedures described above. The present invention relates to manufacturing and strengthening processes for surgical and non-surgical blades.

  Existing surgical blades are manufactured by several different methods, each of which has its own advantages and disadvantages. The most common manufacturing method is a method of mechanically grinding stainless steel. The blade is then honed (by a variety of different methods such as ultrasonic slurrying, mechanical ablation, lapping, etc.) or the blade is electrochemically polished. To obtain a sharp edge. The advantage of these methods is that they are a proven and economical process for manufacturing disposable blades in large quantities. The biggest drawback of these processes is that the quality of the edges varies, so it is still difficult to achieve good sharpness consistency. This is mainly due to the inherent limitations of the process itself. The blade edge radius can be from 30 nm to 1000 nm.

  One relatively new blade manufacturing method uses stainless steel coining instead of grinding. The blade is then electrochemically polished to obtain a sharp edge. This process has proven to be more economical than the grinding method. This process has further been found to produce blades with better sharpness consistency. The disadvantage of this method is that its sharpness consistency is still inferior to that obtained by the diamond blade manufacturing process. Due to the cost of disposable metal blades and the improvement in quality, the use of metal blades in soft tissue surgery is now widely practiced.

  Diamond blades are the best standard blade in sharpness in many surgical industries, especially the ophthalmic surgical industry. Diamond blades are known to be able to cut soft tissue vividly with minimal tissue resistance. The use of a diamond blade is desirable because the sharpness does not change from start to finish even after repeated cutting. Most blade surgeons will use diamond blades because the extreme sharpness and sharpness variability of metal blades is inferior to diamond. The manufacturing process used to manufacture diamond blades uses a wrapping process that achieves an exceptionally sharp and consistent edge radius. The resulting edge radius is from 5 nm to 30 nm. The disadvantage of this process is that it is time consuming and directly results in the cost of manufacturing such a diamond blade reaching from $ 500 to $ 5000. Accordingly, these blades are sold for reuse applications. This process is currently used for other softer materials such as ruby and sapphire to achieve the same sharpness at a lower cost. However, although cheaper than diamonds, surgical quality ruby and / or sapphire blades still have a relatively high manufacturing cost of $ 50 to $ 500, with their edges having only about 200 cases. Has drawbacks. Accordingly, these blades are sold for reuse and limited reuse applications.

  Several proposals have been made to manufacture surgical blades using silicon. However, these processes are limited in their ability to manufacture blades in a variety of shapes and disposable costs. Many of the silicon blade patents are based on anisotropic etching of silicon. An anisotropic etch process is a highly directional process with different etch rates in different directions. This process can produce a sharp cutting edge. However, due to its nature, this process is limited by the blade shape and the bevel angle that can be achieved. Wet bulk anisotropic etching processes, such as wet bulk anisotropic etching processes using potassium hydroxide (KOH), ethylenediamine / pyrocatechol (EDP) and trimethyl-2-hydroxyethylammonium hydroxide (TMAH) baths, Etch along a specific crystal plane to achieve a sharp edge. This plane, generally the (111) plane of silicon <100>, is at an angle of 54.7 ° from the surface of the silicon wafer. This produces a blade with a bevel angle of 54.7 °, which has been found to be clinically unacceptable for most surgical applications because it is too obtuse. When this technique is applied to the manufacture of double bevel blades, this application becomes even more ineligible. This is because the bevel angle is 109.4 °. This process is further limited to the blade profile that it can produce. The etched surfaces are arranged at 90 ° to each other in the wafer. Therefore, only blades with a rectangular profile can be produced.

  The method described in more detail below, which produces surgical and non-surgical blades and other mechanical devices from silicon, causes mechanical damage in the brittle silicon material during one or more machining steps. there is a possibility. In brittle materials, cracks, chips, scratches and sharp edges all serve as crack initiation points. These points serve to cause a sudden failure of the mechanical device when a load or stress is applied to them.

  Other methods for creating sharp edges on blades formed from wafers are well known. In these methods, etching is performed through the wafer using a photomask with isotropic wet or dry etching to form an ophthalmic blade geometry and cutting edge. In this process, the entire circumference of the blade is etched through to form a sharp edge. This through-etching is performed only while the etching mask is in place. This mask roughly defines where the cutting edge is created. The mask is then removed and the blade support is dissolved, releasing the blade (an additional die level cleaning step is required). This method is inefficient and ineffective for the purpose of mass producing high quality ophthalmic blades without defects. This method is inefficient because it adds several steps to the manufacturing process.

  There are also significant constraints inherent in this process regarding the cutting edge geometry. The bevel produced by this process is limited to 45 °, which is inefficient with a single bevel blade, and 90 °, which is impractical with a double bevel blade. In addition, this process strictly limits the bevel width to a maximum wafer thickness for single bevel blades and to a maximum of half the wafer thickness for double bevel blades. These shapes provide inferior cutting tools and prove this not to be adopted in the ophthalmic field.

  Accordingly, there is a need to produce a blade that overcomes the disadvantages of the methods described above. This system and method of the present invention can produce a blade with a diamond blade sharpness at the cost of a stainless steel process that can be made disposable. Furthermore, the system and method of the present invention can produce a large number of blades with strict process control. In addition, the system and method of the present invention can produce surgical blades and various other types of blades having straight and non-linear blade bevels. Furthermore, the system and method of the present invention provides mechanical damage that occurs in silicon crystalline material when a blade (surgical or non-surgical) or other mechanical device is manufactured according to the process described herein. Can be removed.

  The present invention solves the above-mentioned drawbacks and realizes several advantages. The present invention relates to systems and methods for manufacturing surgical blades from crystalline or polycrystalline materials, such as silicon, and to provide grooves of a desired bevel angle or blade shape in a crystalline or polycrystalline wafer by various means. Including machining. The machined crystal or polycrystalline wafer is then stripped uniformly one after another in molecular layers of the wafer material to form a uniform radius cutting edge with sufficient quality for soft tissue surgery. Immerse in an etching solution. The system and method of the present invention provides a very inexpensive means for manufacturing such high quality surgical blades.

  Accordingly, an object of the present invention is a method of manufacturing a surgical blade, the step of mounting a silicon wafer or other crystalline or polycrystalline wafer on a mounting assembly, and a first of a crystalline or polycrystalline wafer. Machining one or more grooves in the surface with a router to form a linear or non-linear groove; and etching one or more of the first surface of the crystalline or polycrystalline wafer; Providing a method comprising the steps of forming a surgical blade, singulating the surgical blade, and assembling the surgical blade.

  Another object of the present invention is a method of manufacturing a surgical blade comprising the steps of mounting a crystalline or polycrystalline wafer on a mounting assembly, and a router on a first surface of the crystalline or polycrystalline wafer. Machining one or more grooves to form a linear or non-linear groove; covering a first surface of a crystalline or polycrystalline wafer with a coating; crystalline or polycrystalline Removing the crystalline wafer from the mounting assembly; reattaching the first side of the crystalline or polycrystalline wafer onto the mounting assembly; and machining the second side of the crystalline or polycrystalline wafer. Etching the second side of the crystalline or polycrystalline wafer to produce one or more surgical blurs Forming a de, comprising the steps of a single fragmented surgical blades, to provide a method and a step of assembling the surgical blades.

  Another object of the present invention is a method of manufacturing a surgical blade comprising the steps of mounting a crystalline or polycrystalline wafer on a mounting assembly and a router on a first surface of the crystalline or polycrystalline wafer. Machining one or more grooves to form a linear or non-linear groove; removing a crystalline or polycrystalline wafer from the mounting assembly; and Reattaching one surface onto the mounting assembly; machining a second surface of the crystalline or polycrystalline wafer with a router to form a linear or non-linear groove; Etching the second side of the polycrystalline wafer to form one or more surgical blades; Forming a crystalline or polycrystalline surface and cured material layer is converted in the steps of the single fragmented surgical blades, to provide a method and a step of assembling the surgical blades.

  Other objects of the invention include ophthalmology, ultra-surgery, heart, eye, ear, brain, reconstruction surgery, cosmetic surgery and biological applications, and various non-medical applications manufactured according to the methods described herein. It is intended to provide several illustrative examples of surgical blades for medical or non-biological applications.

  Another object of the present invention is to increase the strength of mechanical devices and surgical and non-surgical blades made from single crystalline or polycrystalline materials including silicon according to one or more processes described herein. It is to provide a system and method for augmentation.

  Accordingly, it is an object of the present invention to provide a method based on isotropic and anisotropic etching methods that does not have any prior art defects and has all of the advantages discussed herein. It is in. This method makes it possible to form complex blade shapes including, but not limited to, single and double beveled slit knives, trapezoid knives, chisel knives. The above-described method of manufacturing a blade using an isotropic etching process according to some embodiments of the present invention enables the use of an accurate mechanical method to form a V-groove that will ultimately become the blade edge. Subject to restrictions. A method according to one embodiment of the present invention forms a V-groove without applying any mechanical stress to the wafer. By using a combination of photomasking, wet etching (isotropic and anisotropic) and dry etching (isotropic and anisotropic, including reactive ion etching), V-grooves are made into an infinite number of 2 It can be formed in a dimensional shape and at the same time can provide excellent control of the pre-formed bevel angle. After forming the initial V-groove (or groove), the grooved wafer is subjected to a maskless wet isotropic etching process as described herein. The final blade shape and very sharp cutting edge can then be produced.

  The novel features and advantages of the present invention are best understood when the following detailed description of the preferred embodiment is read with reference to the accompanying drawings, in which:

  Various features of the preferred embodiment will now be described with reference to the drawings. In the figures, identical parts are identified by identical reference numerals. The following description of the best mode contemplated for carrying out the invention at the present time should not be taken as limiting. The following description is merely provided to illustrate the general principles of the invention.

  The system and method of the present invention is for the manufacture of a surgical blade used to incise soft tissue. Although the preferred embodiment is shown with a surgical blade, a number of cutting devices can also be manufactured according to the methods detailed below. Thus, throughout these descriptions, reference is made to “surgical blades”, for example, medical razors, lancets, hypodermic needles, sample collection cannulas and other medical sharps. It will be apparent to those skilled in the art of the present invention that many other types of cutting devices, including: Furthermore, blades manufactured according to the systems and methods of the present invention can also be used as other non-medical blades, including, for example, shaving and laboratory (ie, tissue sampling). Furthermore, although described with reference to ophthalmic applications throughout the following description, many other types of medical applications include, but are not limited to, eye, heart, ear, brain, cosmetic surgery and reduction surgery. .

  As is well known to those skilled in the art, the terms “single bevel”, “double bevel” and “facet” are defined. A single bevel refers to a single bevel (slope) on a blade, and the resulting sharp edge is in the same plane as the main surface of the blade. For example, see FIG. 10A, described in detail later. A double bevel refers to one with two bevels on a single blade, and the resulting sharp cutting edge results in a centerline throughout the blade, as shown in FIGS. 10B, 20A and 31C. On substantially the same plane. A facet is a flat edge that exists on a bevel. There can be one, two or more facets per bevel on any blade. Thus, there can be multiple sharp edges (or multiple sets of bevels, each bevel can have one or multiple facets) on any one blade.

  34A-34C show additional views of a surgical blade 340 made in accordance with one embodiment of the present invention. In FIG. 34A, various parameters of the surgical blade are shown. For example, side cutting length, tip to shoulder length, and profile angle are all shown. The value of each parameter depends on the blade design and the expected application. However, due to the advantages of surgical and non-surgical blade manufacturing methods (as described below), the profile angle of certain surgical blades manufactured according to these methods should be smaller than commonly encountered. Can do. By way of example only and not by way of limitation, a profile angle of approximately 60 ° is obtained for a particular blade profile according to one embodiment of the present invention. 34B and 34C show the additional parameters described above.

  An additional industry term and parameter well known to those skilled in the art is the edge radius of the blade. The “cutting radius” or “edge radius” is the radius of the sharp edge that cuts the skin, eye (for ophthalmic applications) or other material / object. For example, if a surgeon is using a blade to cut or open a patient's eye, it is very important, if not essential, that the blade used is as sharp as possible. 35A and 35B show the edge radius of a surgical blade manufactured in accordance with one embodiment of the present invention. FIG. 35B is a view taken along line AA of blade 350 in FIG. 35A. Blades (surgical or non-surgical) manufactured according to embodiments of the invention described below have edge radii from about 30 nm to about 60 nm, and in one embodiment of the invention, have an edge radius of about 40 nm. Can have. Tables I and II show the raw data accumulated in the measurement of the edge radius of a metal blade and the edge radius of a silicon blade manufactured according to embodiments of the invention described below. This data is aggregated by a first curve 362 in FIG. 36, which shows the range of edge radii of blades manufactured in accordance with the embodiments of the invention described herein in the second curve in FIG. It is shown that it is much smaller than the edge radius range of the metal blade as shown by curve 364. A smaller edge radius creates a sharp blade.

  The substrate on which the blades will be manufactured is single crystal silicon with the preferred crystal orientation. However, other crystal orientations of silicon and other materials that can be isotropically etched are also suitable. For example, silicon wafers with orientations <110> and <111> and silicon wafers that are impurity diffused at various resistivity and oxygen content levels can be used. In addition, wafers made of other materials such as silicon nitride and gallium arsenide can also be used. Wafer form is one particularly useful format for substrates. In addition to single crystal materials, polycrystalline materials can be used to manufacture surgical blades. Examples of these polycrystalline materials include polycrystalline silicon. It should be understood that the term “crystal” as used herein refers to both single crystalline and polycrystalline materials.

  Thus, while referring to “silicon wafers” throughout these descriptions, any of the materials described above in conjunction with various orientations, as well as other suitable materials and orientations that may be usable, are contemplated by the present invention. It will be apparent to those skilled in the art of the present invention that it can be used in accordance with certain embodiments.

  FIG. 1 shows a flow diagram of a method for manufacturing a double bevel surgical blade in silicon according to a first embodiment of the present invention. The method of FIGS. 1, 2 and 3 generally describes a process that can be used to manufacture a silicon surgical blade in accordance with the present invention. However, the order of the method steps shown in FIGS. 1, 2 and 3 can be varied to produce different standards of silicon surgical blades or to adapt to different manufacturing environments.

  For example, as shown and described later, FIG. 1 illustrates a method of manufacturing a double bevel blade in accordance with a first embodiment of the present invention, but this method involves multiple (ie, It can also be used to produce more than two facets. 31A-C show such a blade and will be described in detail later. Further, the method as shown and described is made available for producing a variable double bevel blade, as shown in FIG. FIG. 32 will be described in detail later. Furthermore, as another example of a single blade with two (or more) cut surfaces having two (or more) bevel angles, the blade shown in FIGS. By the method shown and described in the specification, it is possible to manufacture at different bevel angles for a plurality of cutting edges. As such, the method of FIGS. 1, 2 and 3 is in accordance with the present invention in that there are many different variations, including the same procedure that results in a silicon surgical blade manufactured in accordance with the spirit and scope of the present invention. It is meant to be representative of all the examples.

  The method of FIG. 1 is used to manufacture a double bevel surgical blade, preferably of a crystalline material such as silicon, according to one embodiment of the present invention, and the method of FIG. In step 1002, a silicon wafer is mounted on a mounting assembly 204. In FIG. 4, a silicon wafer 202 is shown mounted on a wafer frame / UV tape assembly (mounting assembly) 204. Mounting assembly 204 is a common method for handling silicon wafer materials in the semiconductor industry. Those skilled in the art will appreciate that mounting a silicon (crystalline) wafer 202 on the wafer mounting assembly 204 is not essential for manufacturing a surgical blade in accordance with an embodiment of the present invention.

  FIG. 5 shows the same silicon wafer 202 mounted on the same mounting assembly 204, but in a side view (left or right side view, which is symmetrical but not necessarily). In FIG. 5, a silicon wafer 202 is attached to tape 308 which is then mounted on mounting assembly 204. The silicon wafer 202 has a first surface 304 and a second surface 306.

  Referring again to FIG. 1, there is a decision step 1004 after step 1002. Decision step 1004 determines if an optional pre-cut is made on silicon wafer 202 at step 1006 if desired. This precutting can be performed by a laser waterjet 402 as shown in FIG. In FIG. 6, the illustrated laser water jet 402 directs a laser beam 404 onto a silicon wafer 202 mounted on a mounting assembly 204. . As can be seen from FIG. 6, a number of pre-cut holes (ie, through-hole fiducials) 406 are created in the silicon wafer 202 as a result of the collision between the laser beam 404 and the silicon wafer 202.

  The silicon wafer 202 is removed by the laser beam 404. The ability of the laser beam 404 to remove the silicon wafer 202 is related to the wavelength λ of the laser. In one embodiment using a silicon wafer, although other types of lasers can be used, the wavelength that yields the best results is typically 1064 nanometers provided by a YAG laser. If another crystalline or polycrystalline material is used, another wavelength and laser type may be more appropriate.

  The resulting reference through-hole 406 (which can cut multiple holes in this manner) is used to create a groove, particularly when a dicing saw blade is used to machine the groove. It can be used as a guide for machining (described in detail below with respect to step 1008). Also, the reference through hole 406 can be cut by any laser beam (eg, excimer laser or laser water jet 402) for the same purpose. The pre-cut reference through hole is typically cut into a plus “+” shape or a circle. However, the selection of the shape of the reference through hole is made by a specific manufacturing tool and manufacturing environment, and therefore need not be limited to the two shapes described above.

  In addition to pre-cutting the reference through hole using a laser beam, other machining methods can be used. This includes, but is not limited to, for example, a drilling tool, a mechanical grinding tool, and an ultrasonic machining tool 100. . Although the use of these devices is novel with respect to embodiments of the present invention, these devices and their general use are well known to those skilled in the art.

  In order to keep the silicon wafer 202 intact during the etching process and not shattering, pre-cuts can be performed on the silicon wafer 202 before machining the grooves. A laser beam (eg, laser water jet 402 or excimer laser) is described in detail with reference to dicing blade 502 (see FIGS. 7A-7C) to begin machining grooves in its circumference in silicon wafer 202. To be scrolled within the slot of the oval through hole. The machining devices and methods used to make the reference through hole (as described above) are similarly enabled to make the slot for the through hole.

  Referring again to FIG. 1, the next step is step 1008, step 1006 (if the reference through hole 406 is cut into the silicon wafer 202), or steps 1002 and 1004 (steps for attaching the silicon wafer). “Step” 1004 is not a physical manufacturing step; these decision steps are included to show the entire manufacturing process and its changes). In step 1008, the groove is machined into the first surface 304 of the silicon wafer 202. There are several methods that can be used to machine the groove, depending on the manufacturing conditions and the desired design of the finished silicon surgical blade product.

  This machining method can use a dicing saw blade, laser system, ultrasonic machining tool, hot-forging process or router. Other machining methods can also be used. And then each will be described. Grooves machined by any of these methods provide the angle (bevel angle) of the surgical blade. When the grooving machine operates on a silicon wafer 202, the silicon material is in the form of a dicing saw blade, formed by an excimer laser, or formed by an ultrasonic processing tool. It is removed in the shape as expected in the preform. In the case of a dicing saw blade, the silicon surgical blade has only a straight end, and in the latter two methods, the blade can be essentially any desired shape. In the case of a hot forging process, a silicon wafer is heated so that it can be forged, and then between two molds each having a desired groove in a three-dimensional shape that is heated and “formed” into a forgeable silicon wafer. Is pressed. For the purposes of this description, the “machining” of the groove may be a specifically mentioned dicing saw blade, excimer laser, ultrasonic machine or hot forging process, and silicon wafers such as equivalent methods not mentioned. Includes all methods of making grooves in. These methods of machining the groove will now be described in detail.

  7A-7D show the shape of several dicing saw blades used to machine grooves in a silicon wafer according to one embodiment of the present invention. In FIG. 7A, the first dicing saw blade 502 shows an angle Φ that is substantially the resulting angle in the surgical blade after the entire manufacturing process is complete. FIG. 7B shows a second dicing saw blade 504 having two inclined cutting surfaces, each having a cutting angle Φ. FIG. 7C shows a third dicing saw blade 506 having a shaving angle Φ but having a slightly different shape than the first dicing saw blade 502. FIG. 7D shows a fourth dicing saw blade 508 having two inclined cutting surfaces similar to FIG. 7B, each showing a cutting angle Φ.

  The dicing saw blades 502, 504, 506, and 508 shown in FIGS. 7A-7D each have the same cutting angle Φ, but the cutting angle varies for different applications of silicon-based surgical blades. The ability to do so will be apparent to those skilled in the art. Further, as will be described below, a single silicon surgical blade can have multiple cutting edges that differ at different angles contained therein. The second dicing saw blade 504 can be used to increase production for specific designs of silicon-based surgical blades or to produce silicon surgical blades with two or three cutting edges It is said. Various examples of blade designs are described in detail below with reference to FIGS. In one embodiment of the invention, the dicing saw blade is a diamond grit saw blade.

  A special dicing saw blade is used to machine grooves in the first surface 304 of the silicon wafer 202. The dicing saw blade composition is specifically selected to provide the highest surface finish that results while maintaining an acceptable wear life. The blade of the dicing saw blade is shaped with a contour that forms a groove in the resulting silicon wafer 202. This shape will correlate with the shape of the resulting blade bevel. For example, typically a surgical blade has a bevel angle of 15 ° to 45 ° for a single bevel blade and a half bevel angle of 15 ° to 45 ° for a double bevel blade. Selection of the dicing saw blade in relation to the etching conditions provides precise control of the bevel angle.

  FIG. 8 illustrates the operation of a dicing saw blade passing through a silicon wafer mounted on a support backing according to one embodiment of the present invention. FIG. 8 illustrates the operation of a dicing saw blade machine that machines grooves in the first surface 304 of the silicon wafer 202. In this example, any of the dicing saw blades (502, 504, 506 or 508) in FIGS. 7A-7D can be used to make a silicon-based surgical cutting edge. Further, it should be understood that the shape of the blade in FIGS. 7A-7D is not the only possible shape that can be formed for a dicing saw blade. FIG. 9 illustrates a cross-sectional view of a dicing saw blade machining a groove in a silicon wafer taped in accordance with one embodiment of the present invention. FIG. 9 shows an enlarged cross-sectional view of the dicing saw blade assembly shown in FIG. 8 that actually enters the silicon wafer 202. It can be seen that the dicing saw blade 502 does not penetrate the entire silicon wafer 202 and only about 50-90% of the thickness of the silicon wafer 202 penetrates for a single bevel cut. This applies to any method used for the purpose of machining (or forming by hot forging) a single bevel groove. For a double bevel cut by a dicing saw blade or any machining method, machining (or shaping) so that about 25-49% of the thickness of the silicon wafer 202 is spaced from each side of the silicon wafer 202 Is done. FIGS. 10A and 10B show a silicon surgical blade having a single bevel cutting edge and a silicon surgical blade having a double bevel cutting edge, respectively, fabricated according to one embodiment of the present invention.

  As described above, further slots are made cuttable in the silicon wafer 202, particularly when a dicing saw blade is used to machine the grooves. The slot can be cut into the silicon wafer 202 in a manner similar to the reference through hole, ie, using a laser water jet or excimer laser, but serves a very different purpose. Recall that the reference through-hole is used by the trench machine to accurately position the silicon wafer 202 on the trench machine. This is particularly useful when manufacturing double bevel blades. This is because the second machining must be accurately positioned (opposite the silicon wafer 202) to ensure that the double bevel blade is properly manufactured. However, slots are used for other purposes. The slot allows the dicing saw blade to begin cutting the silicon wafer 202 away from the edge (as shown in FIG. 8) so that it does not crush or break the silicon wafer 202. enable. This is one example as shown in FIG. 8A. Referring to FIG. 8, if no slot is used and the groove is machined as shown, the silicon wafer is fairly thin in that area and small stresses cause the silicon wafer to break. It is clear that the etched silicon wafer 202 is prone to breakage along the machined grooves. That is, the machined silicon wafer of FIG. 8 lacks structural rigidity. Compare this with the silicon wafer of FIG. 8C. The machined silicon wafer 202 of FIG. 8C is much stiffer, resulting in improved manufacturing throughput. The silicon wafer 202 machined according to FIG. 8C will be less likely to break than the silicon wafer of FIG. As shown in FIGS. 8A and 8B, the slot can be made wider than the dicing saw blade, and the dicing saw blade can be inserted into the slot to begin machining at an appropriate depth. Made long enough. Therefore, the dicing saw blade does not attempt to cut the silicon wafer 202 during the downward movement that causes crushing and breakage as intended, but starts cutting when it is moving horizontally. FIG. 8C shows a series of slots and machined grooves in the first surface of the silicon wafer 202.

  FIG. 11 shows a block diagram of a laser system used to machine grooves in a silicon wafer according to one embodiment of the present invention. The groove can also be machined by ultrasound, as will be explained with reference to FIG. 12, which will be described in detail later. The advantage of these two methods is that the blades can be manufactured with non-linear complex cutting edge profiles such as a half-moon blade, a spoon blade and a sclerotome blade. FIG. 11 shows a simplified laser machine assembly 900. The laser machine assembly 900 includes a laser 902 that emits a laser beam 904 and a multi-axis control mechanism 906 that is mounted on a base 908. The laser machine assembly 900 may, of course, further include a computer and a network interface, but these are omitted for clarity.

  When machining grooves using the laser machine assembly 900, the silicon wafer 202 is mounted on a mounting assembly 204 that is adapted to be manipulated by the multi-axis control mechanism 906. Through the use of the laser processing assembly 900 and various light beam masking techniques, numerous blade profiles can be machined. The light beam mask is placed inside the laser 902 and careful design prevents the laser 902 from removing silicon material in unintended locations. For double bevel blades, the opposite surface is machined in the same way using pre-cut grooves 206A, 206B or reference through holes 406 for alignment.

  In preparation for a wet isotropic etching step (which will be described in detail with reference to step 1018 of FIG. 1), a laser 902 is applied to the first surface 304 or the second surface 306 of the silicon wafer 202. Used to accurately and precisely machine trench patterns (also called “ablation profiles” for laser use). Multi-axis control and the use of an internal laser light beam mask is used to scan the ablation profile described above on the silicon wafer 202. As a result, a certain shaped groove is obtained and has a shallow slope corresponding to the slope required for the surgical blade product. Various curvilinear cross-sectional patterns can be obtained by this process. There are several types of lasers that can be used in this machining step. For example, an excimer laser or laser water jet 402 can be used. The wavelength of the excimer laser 902 can be in the range between 157 nm and 248 nm. Other examples include YAG lasers and lasers having a wavelength of 355 nanometers. Of course, those skilled in the art will appreciate that a laser beam having a wavelength ranging from 150 nm to 11,000 nm can be used to machine the trench pattern.

  FIG. 12 shows a block diagram of an ultrasonic machining system used to machine grooves in a silicon wafer according to one embodiment of the present invention. The ultrasonic machining uses a precisely machined ultrasonic tool 104 that is used to machine the first surface 304 or the second surface 306 of the silicon wafer 202 using the polishing slurry 102. Executed by. Ultrasonic machining is performed one surface at a time. For double bevel blades, the opposite surface is machined in the same way using the reference through hole 406 for alignment.

  Ultrasonic machining is used to accurately and precisely machine the trench pattern on the surface of the silicon wafer 202 in preparation for a wet isotropic etching step. Ultrasonic machining is performed by ultrasonically vibrating a mandrel / tool (tool) 104. Tool 104 is not in contact with silicon wafer 202 but is in close proximity to silicon wafer 202 and excites polishing slurry 102 by the action of ultrasonic waves emitted by tool 104. The ultrasonic waves emitted by the tool 104 cause the polishing slurry 102 to be machined into the tool 104 and force the silicon wafer 202 to erode against the corresponding pattern.

  Tool 104 is machined by milling, grinding or electrostatic discharge machining (EDM) to create a trench pattern. The resulting pattern on the machined silicon wafer 202 corresponds to the pattern machined on the surface of the tool 104. An advantage of using an ultrasonic machining method over using an excimer laser is that an entire surface of the silicon wafer 202 can have multiple blade trench patterns that are simultaneously ultrasonicated. The process is therefore fast and relatively inexpensive. Furthermore, this process makes it possible to obtain various curved cross-sectional patterns as in the excimer laser processing method.

  FIG. 13 shows a diagram of a hot forging system used for the purpose of forming grooves in a silicon wafer according to one embodiment of the present invention. The groove shape can be hot forged on the wafer surface. This method uses heating the wafer to a malleable state. Subsequently, the wafer surface is pressed between two molds that merge concave patterns against the resulting groove pattern.

  The silicon wafer 202 is preheated in the heating chamber, or the silicon wafer 202 is completely heated by the action of the heated base member 1054 on which the silicon wafer 202 is mounted. After sufficient time has passed at high temperatures, the silicon wafer 202 will be malleable. The heated mold 1052 is then forced down onto the silicon wafer 202 with sufficient pressure to impress a negative image of the heated mold 1052 on the first surface 304 of the silicon wafer 202. The design of the mold 1052 can be made such that there are multiple grooves of various bevel angles, depths, lengths and contours to make virtually any blade that can be imagined. The view shown in FIG. 13 is greatly simplified and exaggerated to clearly illustrate the features of the hot forging method.

  FIGS. 26-29 illustrate a procedure for using a router to machine a straight or non-linear groove in a crystalline material according to one embodiment of the present invention. In FIG. 26, a through hole 622 is formed in the silicon wafer 202. In one embodiment of the present invention, the through hole 622 is necessary to prevent microcracking. As described above, the through-hole 622 is formed in the silicon wafer 202 by one of several different methods including, among other methods, using drilling, ultrasonic machining, laser or laser water jet. can do. The number of through holes 622 is determined by the total number of blades formed in the silicon wafer 202. However, although generally at least two through holes 622 are required per blade (to start and end router processing), this embodiment of the invention is not limited to many through holes 622.

  After all the desired through-holes 622 have been drilled into the silicon wafer 202, the router 620 (showing counterclockwise rotation when viewed from above) is turned up through the through-holes 622 after the router has been raised to a certain rotational speed. Be lowered into. The router 620 is lowered to a desired depth according to software control and moves in a desired direction. See FIG. The software control includes the depth at which the router 620 is lowered (and the depth at which the router 620 is raised when the router processing is completed), the XY direction in which the router 620 moves within the silicon wafer 202, and the router in that XY direction. Controls the speed at which 620 moves. The configuration of router 620 is driven by the required tilt angle for future blade shapes. For example, a surgical blade used for a specific purpose may require a specific enclosed angle and a specific design of the blade. FIG. 28 shows the slope created by the router 620 when routering the silicon wafer 202. For example, if a double bevel blade requires an enclosed angle of 30 °, the router angle should be 150 °.

  The use of router 620 provides a relatively inexpensive means for providing straight and non-linear grooves in silicon wafer 202. As can be seen in FIG. 29, a single blade can have both straight and non-linear portions. Using a single inexpensive means to form the grooves saves time and money in the blade manufacturing process, thereby reducing manufacturing and sales costs.

  FIG. 30 shows a flow diagram of a method for routering straight or non-linear grooves in crystalline material according to one embodiment of the present invention. In step 604, the cutting process results in the required number of through holes 622 in the silicon wafer 202. In step 606, after the router 620 has been increased in its rotational speed to the desired speed, the router 620 is inserted to the desired depth in the first through hole 622. Software control then continues and moves router 620 according to a defined pattern, thereby creating a groove with the desired bevel angle and design (step 608). When the router encounters the last through hole 622, the router 620 is retracted under software control (step 610). This process can be repeated as many times as necessary to produce the optimum amount of blades on the silicon wafer 202 (step 612).

With reference to several methods for machining the grooves, attention is again directed to FIG. Following step 1008, where the grooves are machined into the first surface 304 of the silicon wafer 202, in decision step 2001, a determination must be made as to whether the silicon wafer 202 is to be coated. FIG. 14 illustrates a silicon wafer having a single machined groove with a coating applied to the machined surface according to one embodiment of the present invention. If a coating is applied, then in step 2002, coating 1102 is applied to first surface 304 of silicon wafer 202 according to one of many techniques known to those skilled in the art of the present invention. Can be coated. The coating 1102 is performed to facilitate control of the etch and to provide additional strength to the resulting cutting edge. The silicon wafer 202 is placed in a deposition chamber in which the entire first surface 304 of the silicon wafer 202, including the flat area and the grooved area, is covered with a thin silicon nitride (Si ₃ N ₄ ) layer. The The resulting coating 1102 thickness can range from 10 nm to 2 microns. The coating 1102 can be made of any material that is harder than the silicon (crystal) wafer 202. In particular, the coating 1102 further comprises titanium nitride (TiN), aluminum titanium nitride (AlTiN), silicon dioxide (SiO ₂ ), silicon carbide (SiC), titanium carbide (TiC), boron nitride (BN) or diamond-like crystals. It can consist of a body (diamond-like-crystal: DLC). The coating of the double bevel surgical blade will be described again in more detail later with reference to FIGS. 18A and 18B.

  After coating 1102 is applied in optional step 2002, the next step is step 2003 to remove and reinstall (if the coating is not applied, step 2003 becomes the step after step 1008). In step 2003, the silicon wafer 202 is removed from the tape 308 using the same standard loader. The machine removes the silicon wafer 202 by emitting ultraviolet (UV) light to the UV photosensitive tape 308 to reduce the stickiness of the tape. Instead of the UV photosensitive tape 308, a low adhesive tape or a heat release tape can be used. After sufficient ultraviolet (UV) light exposure, the silicon wafer 202 can be easily lifted from the tape mounting. The silicon wafer 202 is then reattached with the second surface 306 up in preparation for machining the grooves in the second surface 306.

  Step 2004 is then performed on the silicon wafer 202. In step 2004, a groove is machined into the second surface 306 of the silicon wafer 202, as was done in step 1008 to fabricate a silicon-based double bevel surgical blade. FIG. 15 illustrates a cross-sectional view of a dicing saw blade 502 for machining a second groove in a silicon wafer 202 taped in accordance with one embodiment of the present invention. Of course, an excimer laser 902, an ultrasonic machining tool 100 or a hot forging process can be used to machine the second groove in the silicon wafer 202. FIG. 15 shows that the dicing saw blade 502 is machining a second groove in the second surface 306 of the silicon wafer 202. A coating 1102 that is optionally applied at step 2002 is shown. Figures 10A and 10B show the resulting single and double bevel cuts, respectively. In FIG. 10A, a single cut is made on the silicon wafer 202, resulting in a cutting angle Φ in a single blade assembly. In FIG. 10B, the second groove is machined into the silicon wafer 202 at the same angle as the first groove (by any of the groove machining methods described above). The result is a silicon-based double bevel surgical blade that has a cutting edge that exhibits a cutting angle Φ and that provides a double bevel angle 2Φ. FIG. 16 shows a cross-sectional image of a silicon wafer having grooves machined on both sides according to one embodiment of the present invention.

FIGS. 31A-31C illustrate a double bevel multiple facet blade manufactured in accordance with one embodiment of the present invention. In FIG. 31A, a top perspective view of a double bevel multiple facet blade 700 is shown. The double bevel multiple facet blade 700 is a quadruple facet blade manufactured according to the method described herein. The angle θ ₁ indicates the enclosed angle of the first facet sets 704a and 704b, and the angle θ ₂ indicates the enclosed angle of the second facet sets 704c and 704d.

  The bevel and facet shown in the double bevel multiple facet blade 700 can be manufactured by any of the groove forming methods described above. For example, the laser beam 904 can be used to machine a groove to form a bevel in a double bevel multiple facet blade 700. The laser beam 904 creates a first pass for machining the first groove on the first surface of the wafer, resulting in machining the first groove and a second pass with appropriate spacing. The created second groove can be machined. Similarly, the first multiple bevel blade 700 can also be manufactured by the hot forging method described in more detail with reference to FIG. Further, any of the above-described methods of machining the grooves can be used to machine a plurality of grooves to form a double bevel multiple facet blade 700 as shown in FIGS. 31A-31C.

In FIG. 32A, a variable double bevel blade 702 is shown in a top perspective view. The variable double bevel blade 702 can be manufactured according to the methods described herein. At the tip of the blade, the angle θ ₄ starts at an obtuse angle and then becomes more acute as it goes to the shoulder, resulting in an angle θ ₃ . This design strengthens the sharp tip of the variable double bevel blade 702.

The bevel shown in the variable double bevel blade 702 can be manufactured by any of the groove forming methods described above. For example, the laser beam 904 can be used to machine a groove to form a bevel in the variable double bevel blade 702. The laser beam 904 can be adjusted to produce a variable bevel by machining the crystalline material according to software program control. Similarly, the first multiple bevel blade 700 can also be manufactured by the hot forging method described in more detail with respect to FIG. In addition, any of the methods described above for machining the grooves can be used to machine a plurality of grooves to form a variable double bevel blade 702 as shown in FIGS. 32B and 32C show two side perspective views of the variable double bevel blade 702, showing how the bevel angles Φ ₃ and Φ _{4 of the} variable double bevel blade 702 vary with distance from the tip.

  20B and 20D show top perspective views of multiple cutting edge blades that can be manufactured with multiple bevel angles. The method described herein can produce blades, each blade edge having a different bevel angle, such as the blades shown in FIGS. 20B and 20D. 20B and 20D, there are four cutting edges, and each cutting edge can have a different single bevel angle, i.e., a double bevel angle. Further, as described above, each bevel angle can have one or more facets. These are given for illustrative purposes only and are not intended to limit the embodiments of the invention described herein.

  Following the step 2004 of machining the grooves, in decision step 2005, the silicon wafer 202 with grooves machined on both sides is etched at step 1018 or the silicon wafer 202 with grooves machined on both sides is step 1016. You must make a decision about whether to dice. The dicing step 1016 can be performed by a dicing saw blade, a laser beam (eg, excimer laser or laser water jet 402). Dicing is for the resulting strip (step 1018) that is etched using an application specific fixture instead of a wafer boat (described in detail below).

  17A and 17B illustrate an isotropic etching process performed on a silicon wafer having grooves machined on both sides in accordance with one embodiment of the present invention. In the etching step 1018, the machined silicon wafer 202 is removed from the tape 308. The silicon wafer 202 is then placed in a wafer boat and immersed in an isotropic acid bath 1400. The temperature, concentration and agitation of the etchant 1402 are controlled so that the uniformity in the etching process is maximized. The isotropic etching solution 1402 used is made of hydrofluoric acid, nitric acid and acetic acid (HNA). Other combinations and concentrations can be used to achieve the same purpose. For example, water can be substituted for acetic acid. Also, instead of immersion etching, spray etching, isotropic xenon difluoride gas etching and electrolytic etching can be used to achieve the same result. Another example of a compound that can be used in gas etching is sulfur hexafluoride or other similar fluorinated gases.

  The etching process will uniformly etch both sides of the silicon wafer 202 and their respective grooves until the cross-sections of the facing grooves meet. When the cross sections of the grooves meet, the silicon wafer 202 will be immediately removed from the etchant 1402 and rinsed. The cutting edge radius achieved and expected by this process ranges from 5 nm to 500 nm.

  Isotropic chemical etching is a method used to remove silicon in the same way. In the manufacturing method according to an embodiment of the present invention, the cross section on the surface of the wafer produced by the above-described machining is uniformly submerged and intersects the cross section of the opposite surface of the wafer (if a single bevel blade is desired) Will cross the opposite surface of an unmachined silicon wafer). Isotropic etching is used to achieve the desired sharpness of the blade while maintaining the blade angle. Attempts to cross the wafer cross-section by machining alone will fail because the desired end geometry is too delicate to withstand the mechanical and thermal forces of machining. Each acidic component of the isotropic etching solution (etching solution) 1402 has a unique function in the isotropic acid bath 1400. First, nitric acid oxidizes exposed silicon, and secondly, hydrofluoric acid removes oxidized silicon. Acetic acid acts as a diluent during this process. Accurate control of composition, temperature and agitation is necessary to obtain reproducible results.

  In FIG. 17A, a silicon wafer 202 without a coating 1102 is placed in an isotropic etch bath 1400. Note that each surgical blade, first surgical blade 1404, second surgical blade 1406, and third surgical blade 1408 are coupled together. When the etchant 1402 acts on the silicon, the layer molecules are removed one after another and the two angles 1410 and 1412 (of the first surgical blade 1404) are the next surgical blade (second surgical blade). At the point of connection with the surgical blade 1406), the width of the silicon (ie, the surgical blade) is reduced until these two angles 1410 and 1412 meet. As a result, several surgical blades (1404, 1406 and 1408) are formed. Note that the same angle is maintained throughout the isotropic etching process, except that the silicon material has been reduced as the silicon material is dissolved by the etchant 1402.

18A and 18B illustrate an isotropic etching process in a silicon wafer having grooves machined on both sides according to another embodiment of the present invention and having a coating layer on one side. 18A and 18B, the tape 308 and coating 1102 are left on the silicon wafer 202 so that the etching process only affects the second surface 306 of the silicon wafer 202. During the etching process, the wafer need not be attached to the tape, which is only a matter of manufacturing choice.
Also, the isotropic etch material 1402 acts exclusively on the exposed silicon wafer 202 to remove silicon material (in succession), but maintains the same angle as machined in step 2004 (this surface is the first). Because it is the second surface 306). As a result, in FIG. 18B, the silicon-based surgical blades 1504, 1506 and 1508 have the same angle as machined in steps 1008 and 2004. This is because the tape 308 is on the first side 304 and the optional coating 1102 is on the second side 306 so that the isotropic etchant 1402 is allowed to level the silicon molecules along the surface of the machined groove. This is to remove one layer. The first surface 304 of the silicon wafer 202 is not etched at all, resulting in additional strength to the finished silicon-based surgical blade.

  Another advantage of using the optional step 2002 to deposit the coating 1102 on the first surface 304 of the silicon wafer 202 is that the cutting edge (first surface with the groove machined) is stronger than the silicon substrate. The coating 1102 has characteristics (the coating is preferably made of a silicon nitride layer). Thus, applying the coating 1102 results in a stronger and more durable cutting edge. The coating 1102 also provides a wear barrier to the blade surface that is desirable for blades that contact steel in an electromechanical reciprocating blade device. Table III shows a general specification that dictates the strength of a silicon-based surgical blade made using coating 1102 (silicon nitride) without using coating 1102 (silicon).

  Young's modulus (also known as elastic modulus) is a measure of the inherent stiffness of a material. The greater the Young's modulus, the greater the stiffness of the material. Yield strength is the point at which a loaded material transitions from elastic deformation to plastic deformation. In other words, the yield strength is the point at which the material will no longer bend and will permanently distort or break. After etching (with or without coating 1102), the etched silicon wafer 202 is thoroughly rinsed and cleaned to remove any remaining etchant 1402 chemicals.

  FIG. 19 shows the resulting cutting edge of a double bevel silicone surgical blade manufactured according to one embodiment of the present invention and having a coating on one side. The radius of the cutting edge 1602 is typically from 5 to 500 nanometers, similar to that of a diamond surgical blade, but manufactured at a much cheaper cost. After performing the etching process of step 1018, a silicon-based surgical blade can be attached according to the same step 1020 as attachment steps 1002 and 2003.

  Following the attachment step 1020, in step 1022, a silicon-based surgical blade (silicon blade) can be singulated. This means that each silicon blade is separated by use of a dicing saw blade, laser beam (eg, laser water jet 402 or excimer laser) or other suitable means to separate the silicon blades from each other. As one skilled in the art will appreciate, lasers having a wavelength ranging from 150 nm to 11,000 nm can be used. An example of a laser in this wavelength range is an excimer laser. A unique feature of laser water jets (YAG lasers) is that curved, intermittent patterns can be scanned in a spiral pattern within the wafer. This provides the manufacturer with the flexibility to produce a virtually unlimited number of non-blade blade profiles. Laser water jets use water flow as a wave guide that allows the laser to cut like a band saw. As described above, this cannot be achieved with a state-of-the-art dicing machine that can only dice with a continuous linear pattern.

  In step 1024, a singulated surgical silicon blade is mounted on the blade handle assembly in accordance with the customer's specific wishes. However, prior to the actual “pick and place”, the etched silicon wafer 202 (mounted on the tape and frame or tape / wafer frame) is ultraviolet (UV) in the wafer mounting machine. Irradiation with light reduces the adhesiveness of the tape 308. The silicon wafer 202 still on the “reduced tack” tape and frame or tape / wafer frame is then loaded into a commercially available mold mounting assembly system. Recall that we have previously stated that the order of certain steps can be changed according to different manufacturing environments. One such example is the singulation step and the radiation step with UV light, and the order of these steps can be interchanged if necessary.

  The mold mounting assembly system removes the etched individual silicon surgical blades from the "reduced tack" tape and wafer or tape / wafer frame and places the silicon surgical blades in their respective holders. Install within the desired tolerances. Epoxy resin or adhesive will be used to attach the two components. Other assembly methods including thermal staking, ultrasonic staking, ultrasonic welding, laser welding or eutectic bonding can be used to attach the silicon surgical blade to its respective substrate. Finally, at step 1026, a fully assembled silicon surgical blade with a handle is packaged to ensure sterility and safety and transported for use according to the design of the silicon surgical blade.

  Other assembly methods that can be used to attach the surgical blade to the holder include another use of a slot. As described above, the slot can be made by a laser water jet or excimer laser, which is intended to provide an opening for the dicing saw blade to engage the silicon wafer 202 when machining the slot. Used. An additional use of the slot is to provide the blade with a receptacle for receiving one or more struts of the holder. FIG. 24 shows such an arrangement. In FIG. 24, the completed surgical blade 2402 has two slots 2404 a, 2404 formed in its holder boundary region 2406. These are connected to the columns 2408a and 2408b of the blade holder 2410. The slot can be cut into the silicon wafer 202 at any point in the manufacturing process, but is preferably performed prior to singulation of the surgical blade. Before being connected, an adhesive can be applied to the appropriate area to ensure a firm hold. The cover 2412 can then be glued as shown to provide the finished appearance to the final product. The purpose of performing this strut-slot assembly is to provide additional resistance to the tensile forces that the blade 2402 may encounter during incision.

  Having described the manufacturing process of a silicon-based double bevel surgical blade, attention is now directed to FIG. 2, which shows a flow diagram of a method for manufacturing a single bevel surgical blade in silicon according to a second embodiment of the present invention. To do. Steps 1002, 1004, 1006, 1008 in FIG. 1 are the same as the method shown in FIG. 2, and therefore, these steps will not be described repeatedly. However, the method of manufacturing a single bevel surgical blade differs from the method of manufacturing a double bevel blade in the next step of the method, step 1010, and will therefore be described in detail.

  Step 1010 following step 1008 determines whether to remove the machined silicon wafer 202 from the silicon wafer mounting assembly 204. If the single trench silicon wafer 202 is removed (at step 1012), then an additional option is to dice the single trench wafer at step 1016. In an optional removal step 1012, the silicon wafer 202 is removed from the tape 308 using the same standard loader.

  If the silicon wafer 202 is removed at step 1012, then optionally, at step 1016, the silicon wafer 202 may be cut into small squares (ie, the silicon wafer 202 is cut into strips). The dicing step 1016 can be performed by a dicing blade, excimer laser 902 or laser water jet 402. The dicing (as described in detail later) corresponds to the resulting strip that is etched (step 1018) using a custom fixture instead of a wafer boat. After the dicing step 1016, removal step 1012, or machine groove machining step 1008, the next step in the method for manufacturing a silicon-based single bevel surgical blade is step 1018. Step 1018 is the etching step already described in detail above. Thereafter, steps 1020, 1022, 1024 and 1026 follow. These steps are all those steps detailed above with respect to the production of a silicon-based double bevel surgical blade and therefore need not be described again.

  FIG. 3 shows a flow chart of an alternative method of manufacturing a single bevel surgical blade in silicon according to a third embodiment of the present invention. The method shown in FIG. 3 is exactly the same as the method shown in FIG. 2 by steps 1002, 1004, 1006, 1008. However, after step 1008 in FIG. 3, there is a coating step 2002. The coating step 2002 is described above with respect to FIG. 1 and need not be described again in detail. The result of the coating step is the same as previously described, with the machined surface of the silicon wafer 202 having a layer 1102 thereon.

  Following the coating step 2002, in step 2003, the silicon wafer 202 is removed and reattached. This step is also exactly the same as that described above with respect to FIG. 1 (step 2003). As a result, the coated surface of the silicon wafer 202 is placed face down on the mounting assembly 204. Thereafter, steps 1018, 1020, 1022, 1024, and 1026 perform all that is described above in detail. The end result is a single bevel surgical blade with a first surface 304 (machined surface) with a coating layer 1102 to improve the strength and durability of the surgical blade. 23A and 23B show this coated single bevel surgical blade and will be described in more detail.

  Figures 23A and 23B illustrate an isotropic etching process in a silicon wafer having grooves on one side machined according to a further embodiment of the present invention and a coating layer on the opposite side. As described above, the silicon wafer 202 has a coating 1102 coated on the first surface 304, as shown in FIG. To touch. The silicon wafer 202 is then placed in a bath 1400 that contains the etchant 1402 described in detail above. The etchant 1402 initiates etching of the second surface 306 (“upper surface”) of the silicon wafer 202 and removes layers of silicon molecules one after another. After some time, the thickness of the silicon wafer 202 is reduced by the etchant 1402 until the second surface 306 contacts the first surface 304 and the coating 1102. The result is a single beveled surgical blade based on silicon coated with silicon nitride. As shown and described with respect to FIGS. 18A, 18B and 19, all of the advantages described above having a silicon nitride cutting edge (or cutting edge coated with silicon nitride) apply equally to this type of blade.

  20A-20G show various examples of silicon-based surgical blades that can be manufactured according to the method of the present invention. Using this method, various blade designs can be manufactured. Blades with single bevels, symmetric and asymmetric double bevels and curved cutting edges can be produced. For single bevels, machining is performed on only one side of the wafer. Single edge chisel (FIG. 20A), 3 edge chisel (FIG. 20B), slit, 2 edge sharp (FIG. 20C), slit, 4 edge sharp (FIG. 20D), stub, 1 Various blade shapes such as edge sharp (FIG. 20E), keratome, one edge sharp (FIG. 20E), half-moon shape (cursent), curved sharp edge (FIG. 20G) can be produced. The profile angle, width, length, thickness and bevel angle can be changed with this method. This method can be combined with conventional photolithography to create more variations and features.

  FIGS. 21A and 21B show side views, at a magnification of 5,000, of silicon surgical blades and stainless steel surgical blades, respectively, manufactured according to one embodiment of the present invention. Note the difference between FIGS. 21A and 21B. FIG. 21A is much smoother and more uniform. FIGS. 22A and 22B show top views of the cutting edges of a silicon surgical blade and a stainless steel surgical blade, respectively, manufactured according to one embodiment of the present invention at a magnification of 10,000. Again, the difference between FIGS. 22A and 22B is that the former, which is the result of the method according to one embodiment of the present invention, is much smoother and more uniform than the stainless steel blade of FIG. 22B. .

  FIGS. 25A and 25B show cross-sectional perspective views of a cutting edge made of crystalline material and a cutting edge made of crystalline material that includes a layer conversion process in accordance with one embodiment of the present invention. In another embodiment of the present invention, the surface of the substrate material can be chemically converted to a new material 2504 after etching the silicon wafer. This step is also known as the “thermal oxidation, nitride conversion” step or the “silicon carbide conversion of the silicon surface” step. The advantage of converting the blade surface into a substrate material compound is that a new material / surface can be selected to produce a harder cutting edge. However, unlike the coating, the blade edge maintains the shape and sharpness in the post etch step. Note that in FIGS. 25A and 25B, the depth of the silicon blade has not changed due to this conversion process. “D1” (the depth of the silicon blade having only silicon) and “D2” (the depth of the silicon blade having the conversion layer 2504) are equal.

  FIGS. 33A-33D show some examples of surgical blades that can be manufactured according to the method of the present invention and used in ophthalmology. FIG. 33A shows a slit blade / knife 720 that can be used for ophthalmic cataract surgery purposes. The slit blade / knife 720 has a first bevel set 722a and a second bevel set 722b. The first and second bevel sets 722a, 722b can each be the same or different angle single bevel, or the same or different angle double bevel, or the bevel sets 722a, 722b can each be a multiple bevel. And one or more facets. The combination of bevel angle, blade angle, thickness, and number of facets are all design criteria that can be varied depending on the particular application of the slit blade / knife 720, and are described herein according to embodiments of the present invention. It can be manufactured according to the disclosed method.

  FIG. 33B shows a microkeratome blade 724 that can be used in refractive surgery (LASIK ™) ophthalmic surgery. The microkeratome blade 724 has a single bevel 726, which can be a single or double bevel and has one or more facets. With respect to the surgical blades shown in FIGS. 33A-33D and elsewhere herein, the combination of bevel angles, facets, their arrangement and configuration is virtually infinite. The microkeratome blade 724 shows a double bevel 726. As described above, holes 728a and 728b are enabled to attach microkeratome blade 724 to the handle.

  FIG. 33C shows a pocket blade / knife 730 that can be used in cataract ophthalmic surgery. The pocket blade / knife 730 shown in FIG. 33C has a single blade that is substantially circular. The circle is preferred, but is not essential, and other curved shapes (such as an ellipse) can be used instead. The blade can be a single, double or multiple bevel blade, or a combination thereof, as described above. FIG. 33D shows a meniscal blade / knife 734 that can be used in cataract ophthalmic surgery. The meniscal blade / knife 734 shown in FIG. 33D has a single oval blade. Again, the oval shape is preferred but not essential. The meniscus blade / knife 734 preferably has a single bevel angle blade, but as described above, each bevel can be a single or double bevel blade having one or more facets, or a combination thereof. .

  Referring to FIG. 1, after step 1018, a determination is made whether to convert the surface (decision step 1019). When adding a conversion layer (“Yes” path of decision step 1019), the conversion layer is added in step 1021. The method then proceeds to step 1020. If no conversion layer is added (decision step 1019, “No” path), the method proceeds to step 1020. This conversion process requires a diffusion furnace or a high temperature furnace. The substrate is heated to a temperature above 500 ° C. under vacuum or in an inert environment. The selected gas is metered and fed to the furnace at a controlled concentration. As a result of the high temperature, the gas diffuses into the silicon. As it diffuses into the silicon, the gas reacts with the silicon to form a new compound. This new material is created by diffusion and chemical reaction with the substrate, rather than depositing a coating, so that the original shape (sharpness) of the silicon blade is preserved. An additional advantage of the conversion process is that the optical refractive index of the conversion layer is different from that of the substrate so that the blades appear colored. Its color depends on the composition and thickness of the converted material.

  A single crystalline substrate material with a converted surface also exhibits better fracture resistance and wear resistance than non-converted blades. By changing the surface to a harder material, the tendency of the substrate to form crack initiation sites and break along the crystal plane is reduced.

  Another example of a manufacturing step that can be performed with some compatibility is a matte-finish step. In many cases, particularly when manufactured with surgical blade embodiments, the silicon surface of the blade reflects light well. This can distract the surgeon if the blade is used under a microscope with an illumination source. Thus, the surface of the blade can be a matte surface, as opposed to a shiny surface, with a matte finish that diffuses incident light (eg, from high intensity lamps used during surgery). . The matte finish is made by irradiating the blade surface with a suitable laser to evaporate the material in the region of the blade surface according to a specific pattern and density. Although not necessarily so, the region is generally in the shape of the emitted laser beam, so the shape of the region from which the material has been removed is circular. . The size of the removed circular area is 25-50 microns in diameter, again depending on the manufacturer and the type of laser used. The depth of the removed circular area is 10-25 microns.

  The “density” of the removed circular area refers to the overall percentage of the surface area contained by the removed circular area. A “removed zone density” of about 5% significantly cloudes the normally smooth and specular appearance of the blade. However, even if all the removal areas are arranged at the same position, the effect of the mirror surface of the remaining part of the blade is not affected. Thus, the removed circular area is randomly placed over the entire surface of the blade. In practice, a graphic file can be created to randomly place the dents to achieve the desired effect of randomness on a particular removed area density and pattern. This graphic file can be created manually or automatically by a program in the computer. Additional functions that can be implemented are the serial number on the blade, the manufacturer's logo, the name of the surgeon or hospital name.

  Typically, a gantry laser or galvo-head laser machine is enabled to make a matte finish on the blade. The former is slow but extremely accurate, and the latter is fast but not as accurate as a gantry laser. The overall accuracy is not important and the galvo-head laser machine is a useful tool because the production speed directly affects the cost. Galvo-head laser machines can travel thousands of millimeters per second, resulting in an etch time for the entire removal area of about 5 seconds for a typical surgical blade.

  FIG. 37 shows a comparison of the surface roughness range of a blade made of metal and a blade made of silicon according to an embodiment of the present invention.

  An additional parameter for surgical and non-surgical blades is surface roughness characteristics. Surface roughness is an important parameter because it determines how slippery the skin or material is on the blade after the initial cut is made by the cutting edge. A rough surface tends to catch or trap the skin or material, and a smoother surface allows the skin or material to move more easily over the blade. A rough blade surface can cause laceration or tearing, which in the worst case scenario makes the surgeon's incision (during surgical use) unstable. Such a scenario occurs very rarely. Blades or mechanical devices made from silicon in accordance with the above-described embodiments of the present invention can have a much smoother surface that is much smoother than metal blades and substantially free of surface defects. Table IV shows the measured surface roughness of the metal blade, and Table V shows the measured surface roughness of the silicon blade manufactured according to the above-described embodiment of the present invention. Both these tables show the surface roughness measured near the tip of the blade. FIG. 37 shows two curves, a first curve 372 and a second curve 374. These curves represent the range of surface roughness values Ra for silicon blades (first curve 372) and metal blades (second curve 374) manufactured according to the embodiments of the invention described above.

  FIG. 38 illustrates an additional method of manufacturing a silicon surgical blade in accordance with one embodiment of the present invention. The method for manufacturing a silicon surgical blade described in FIG. 38 produces a sufficiently strong blade that can be used in place of a metal blade manufactured for similar purposes (ie, ophthalmic surgical applications). Many of the steps described with respect to FIGS. 1-3 are enabled in method 380, but are not described for the sake of brevity. For example, the dicing step 1016 and the step of adding a conversion layer (step 1019) can be performed in the method 380, but they have been omitted for the reasons described above. Furthermore, when possible, some steps maintained the same sign as used above to avoid confusion. In other examples, the new code is used if it appears that the steps look the same, but actually include steps that are slightly different from those described above. Further, in the following, the well-known groove forming (or dicing) step, reference through hole forming step and other steps will be described, and the same equipment as described above (for example, laser water jet, ultrasonic machining, Diamond saw blade) can be used to create the features described below.

  Method 380 is a laser cut no. Beginning at step 382 with 1. In FIG. 1 creates a reference circle 386 (shown in FIG. 39) for aligning the silicon wafer 202 with respect to the laser and trenching dicing equipment. Laser cut No. 1 creates a crosshair 388 that serves as a reference for aligning the groove with the trench dicing machine, and a slot 390 that is cut to create the side edges of the blade (see FIG. 42).

  In step 1008, a bevel 392 is applied according to various methods and equipment described in more detail previously (see FIG. 40). In step 384, the laser cut No. 2 makes the horseshoe 394 shown in FIG. The resulting wafer 420 ready for etching step 1018 is shown in FIG. The laser cutting step creates mechanical damage caused in the brittle silicon material. The etching step removes the mechanically caused damage. By removing the mechanically induced damage, the stress concentration points are also removed, resulting in a considerable increase in the yield strength of the material (silicon). An isotropic etchant polishes the surface of the material, in this case both the blade edge and the non-blade edge. The etchant can consist of hydrofluoric acid, nitric acid and acetic acid. In brittle materials, cracks, chips, scratches and sharp edges all function as crack initiation points. These locations serve to cause a sudden failure of the mechanical device when a load or stress is applied to them. By eliminating or minimizing crack initiation defects, the durability of the material is increased.

  Following the etching step 1018, a blade is attached (step 1020), singulated (step 1022), mounted (step 1024), and packaged according to customer preferences (step 1026). Steps 1020-1026 were described above in more detail. Therefore, the description thereof will not be repeated here for the sake of brevity.

  39-42 show a silicon wafer processed according to the method described in FIG. 38 for manufacturing a silicon surgical blade. FIG. 43 illustrates a silicon surgical blade that can be manufactured according to the method of one embodiment of the present invention as described above with respect to FIGS. Some improvements in method 380 improve the mechanical strength properties. This will now be described in more detail. For example, in this embodiment of the invention, the horseshoe shown in FIG. 43 is made larger than before. In addition, the laser cut No. described above with reference to step 382 in FIG. 1 cuts a slot 390 that creates the edge of the blade. This is done in such a way that the maximum length of the non-blade edge of the blade can undergo etching (step 1018), which increases the mechanical strength of the blade. Laser cut No. 1 further creates a flange 396 (see FIG. 43). When the flange is made larger, the laser cut no. A better defined horseshoe made in step 2 (step 384) is obtained. Furthermore, the groove formation process cuts each “snowflakes”. A “snowflakes” pattern is created by the groove forming step 1008 as shown in FIG. They are shown as bevel 392. There is no cut between the “snowflakes” (bevel 392). This increases the mechanical strength and integrity of the wafer 202. With respect to laser cutting, it is theoretically possible to vary the pulse width and / or pulse repetition frequency (PRE) to minimize mechanical damage to the silicon.

  The method 380 described above with respect to FIGS. 38-43 includes laser ablation, routering, diamond wheel grinding, ultrasonic grinding, lapping, polishing, stamping, embossing, ion milling, plasma etching (ie, RIE, DRIE, ICP and ECR). ) To remove the damage caused in several different machining embodiments. Method 380 also improves the quality of the finished surface produced by conventional anisotropic or isotropic wet etching processes using, but not limited to, KOH, NaOH, CeOH, RbOH, NH4OH, TMAH, EDP or HNA. It can be used to make

  The etchant (HNA) is an oxidation / reduction etchant for silicon. Under appropriate conditions, the liquid forms a microelectrochemical cell that functions as an anode / cathode pair that etches away the silicon substrate material and the temporarily formed silicon dioxide. This type of reaction acts equally on all surfaces. This means that the surface irregularities are substantially rounded or easily washed away. The resulting surface is substantially defect-free, has a spectral mirror-like appearance, and has a surface roughness on the order of 100 angstroms.

  A test was performed on a sample of silicon processed according to the method described above with respect to FIGS. These silicon samples are known as “coupons”. The strength of the silicon coupon was measured as a function of the way it was processed. According to the test results, using the method described above with respect to FIGS. 38-43, the bending strength (MOR) measured by the three-point bending test is significantly increased. Mechanical devices prepared according to the method of the embodiments of the invention shown and described with respect to FIGS. 38-43 and other silicon manufacturing processes according to the embodiments of the invention described herein, using the data described below. The strength of surgical and non-surgical blades can be compared.

  Due to the brittle failure mode of single crystal silicon, it was necessary to test coupons that accurately represented silicon products manufactured according to any one of the various methods of the present invention described above. Average MOR values and statistical distribution values are necessary to meaningfully characterize the strength of the material.

  When performing an intensity measurement test, edges diced with a diamond wheel, edges cut using a short pulse YAG laser manufactured by Gem City, and edges cut using a long pulse YAG laser manufactured by Synova are evaluated. It was. In addition, these three surfaces were tested after 50μ etching Si and 150μ etching Si. The etchant serves to remove the damage / stress concentration sites caused by the cutting method, and the etchant can be used to further reduce the number of completed edges that have defects that make them fragile.

For each case, 10 coupons of 20 mm x 7 mm on Instron were pushed using the bending mode until broken. In each case, the average MOR increased considerably when the sidewalls were etched after cutting. Data is tabulated in Table VI below. In Table VI, t ₀ indicates the initial thickness of the coupon. The higher MOR values can be attributed to etching that smooths the side wall chips or scratches, as shown in FIGS. In Figure 44 to 52, _{t r} instructs the final thickness of the coupon. By smoothing the side wall chips or scratches, the overall number of sites in the coupon volume that can initiate a sudden crack is greatly reduced. The data of the portion etched up to 250μ (excluding the Gem City device etched to an etching depth of about 300μ to about 250μ) was batch processed and the distribution was analyzed. This data agrees with a normal distribution with an average MOR of 1254 MPa and a standard deviation of 455 MPa.

  The following conclusions can be drawn with certainty based on these test results.

  • The depth of damage created by the Gem City laser is significantly greater than the depth of damage of dicing and Synova lasers. The strength (170 MPa) of the portion cut with the Gem City laser is half the strength of the portion (325 MPa) cut with the Synova laser.

  The strength of the part cut with the Synova laser (325 MPa) is about 60% of the strength of the part cut with the Disco dicing saw (502 MPa). This means that the depth of damage with the Synova laser is greater.

  -Etching of 50μ material gave very similar results with Disco cut (1230 MPa) and Synova laser cut (1300 MPa). Both of these values are more than twice the strength of the part that was diced and not etched.

  53A-53C show the results of a comparison made between a diamond blade, a metal blade, and a silicon blade manufactured in accordance with the embodiments of the invention described herein above. According to FIG. 53A, a blade manufactured from silicon manufactured according to the embodiments of the present invention described hereinabove exhibits a higher peak stab force than a diamond blade. Silicon blades have better peak puncture properties than metal blades (compare first black circle 532 (diamond blade), second black circle 534 (silicon blade) and third black circle 536 (metal blade) ).

  Silicon blades manufactured in accordance with the embodiments of the invention described hereinabove can be significantly sharper than metal blades (can be approximately equal to that of diamond blades), and have been previously described with respect to Tables IV and V. (As explained) can be much smoother than metal blades.

  53B and 53C illustrate the pressure and test media required to cause a wound gap between a diamond blade, a metal blade, and a silicon blade manufactured in accordance with an embodiment of the present invention. Shows the results of the comparisons made with respect to the required force.

  The steps in the method 600 shown in the flow diagram of FIG. 63 may form part of another method for manufacturing a surgical or non-surgical blade described above with respect to FIGS. It is said. The method 600 can be used to make a more complex blade than the other methods described so far. In the following, method 600 will be described with respect to silicon wafer 202. However, the method 600 and other methods described herein are not limited to those in the art and can be used with wafers 202 made of other materials, particularly including SiC, sapphire. The contractor can understand. These materials can be single crystalline or polycrystalline materials.

  The method 600 is performed after the reference through hole is cut in the silicon wafer (wafer) 202 in step 1004 according to the method of FIGS. 1, 2, and 3 and step 382 according to the method of FIG. These reference through holes are used to align the wafer 202 in the various machines used in subsequent steps of the manufacturing process. At step 2000 of method 600, a photoresist layer 540 is applied to the first surface of wafer 202. This is illustrated in FIG. If a double bevel blade is desired, a photoresist layer 540 is applied to both sides of the wafer 202. This will be described in detail later. In step 2002, the photoresist layer 504 is baked and a patterned photomask 544 is disposed on the photoresist-covered wafer 202, and then the baked photoresist layer 540 and the patterned photomask are placed. A wafer 202 having 544 is exposed with ultraviolet light 542 for a specified time. As will be appreciated by those skilled in the art, not only ultraviolet light can be used to expose the photoresist layer 540, but x-rays, as well as other types of radiation (depending on the type of photoresist material used) may be used. it can. Both negative and positive photoresist materials can be used. As will be appreciated by those skilled in the art, the patterned photomask 544 depends on the desired bevel angle and the type of photoresist material and etching method used.

  As a result of exposure with ultraviolet light 542 and subsequent phenomena, the photoresist layer 540 becomes a patterned photoresist layer 541, and the pattern of the patterned photomask 544 is in the patterned photoresist layer 541. Duplicated. In a positive photoresist material, the portion of the photoresist material exposed by x-rays, ultraviolet light or other radiation is the portion that is removed during the phenomenon. The opposite is true for negative photoresist materials. FIG. 55A shows a cross-sectional view of the wafer 202 of FIG. 55 with a patterned first photomask 544A disposed on the photoresist layer 540 exposed by ultraviolet light 542, and FIG. 55A is a cross-sectional view of the wafer 202 of FIG. 55A after the exposure is completed, the photoresist layer 540 is developed to form a patterned photoresist layer 541 and the patterned first photomask 544A is removed. Show. 56A and 56B show other examples of the placement of a patterned second photomask 544B, exposure to ultraviolet light, and phenomena similar to the example shown in FIGS. 55A and 55B. If a double bevel blade is desired, steps 2000 and 2002 can be repeated for the other side of the wafer 202.

  Following step 2002, method 600 proceeds to decision step 2003. As a result of steps 2000 and 2002, the first surface of wafer 202 has a patterned first photoresist layer 541 thereon. In decision step 2003, it is determined whether to manufacture a double bevel blade. When manufacturing a double bevel blade (decision step 2003 "yes" path), it is determined whether both sides are being processed. If both sides have not yet been processed (decision step 2001, “No” path), method 600 proceeds again to steps 2000 and 2002, where a second photoresist layer 540 is present on the second side of wafer 202. At step 2002, the second surface is baked and a patterned second photomask 544B is disposed on the second photoresist layer 540. The second photoresist layer 540 is then exposed with ultraviolet light, X-rays or other types of radiation through a patterned second photomask 544B. As a result, the second photoresist layer 540 becomes the patterned second photoresist layer 541. The method then returns to step 2003, where the method determines that this is the wafer 202 on which one or more double bevel blades are to be fabricated (“Yes” path of decision step 2003). ). The method 600 then determines that both sides of the wafer 202 have been processed (“Yes” path of decision step 2001), and the method 600 proceeds to step 2005. In step 2005, the wafer 202 covered with the first and second photoresist layers 540A, 540B in which both the first surface and the second surface are respectively patterned is developed to form the patterned first. And certain portions of the second photoresist layer 540A, 540B are removed. As described above, which part of the patterned photoresist layers 541A and 541B is developed and removed depends on whether the photoresist is a negative photoresist material or a positive photoresist material. . Method 600 then proceeds to step 2004. This step will be described in more detail later.

  If, after first passing through steps 2000 and 2002, it is determined not to produce a double bevel blade (“No” path of decision step 2003, ie, a single bevel blade), method 600 proceeds to step 2005. In step 2005, a portion of the patterned first photoresist layer 541 is removed from the wafer 202 that is covered only by the patterned first photoresist layer 541 on the first surface. Developed. As described above, which portion of the patterned photoresist layer 541A is developed and removed depends on whether the photoresist is a negative photoresist material or a positive photoresist material. Method 600 then proceeds to step 2004. This step will be discussed in more detail later.

  The patterned photomask 544 used on the photoresist layer 540 is selected based on the desired bevel angle of the cutting device to be formed. An appropriate pattern is selected based on whether the etching method, step 2004, described in more detail below, is wet, dry, isotropic or anisotropic. For example, FIGS. 55A and 55B and FIGS. 56A and 56B used different patterned photomasks 544 because different etching methods were used. Many combinations of etching are possible, which can be extended to multiple masks and etching iterations to form almost all bevel angles. As an example that does not imply an example for limitation, use a patterned first photomask 544A, then a first etching method, then a patterned second photomask 544B, then the first or A second etching method can be used.

  In step 2004, the wafer 202 is etched. Etching is the process of removing the crystalline material layer that makes up the wafer 202 to create a blade (surgical or non-surgical) or other type of tool, as described above. In this example, etching is used to form grooves that define the shape and angle of the blade. As previously mentioned, the groove forming step may be performed by various mechanical methods, including cutting using a diamond saw blade or router, generally in step 1008 of the method shown in FIGS. Or it is performed by forming a groove using an ultrasonic processing device. Following the trench forming etch, the patterned photoresist layer 541 is removed and an additional etch is performed to complete the material removal process, actually forming the sharp edges of the blade. As described above, this process is somewhat complex, but this process allows manufacturers to produce very complex blade designs that include multiple bevels, multiple bevel angles, and various profile angles.

  In step 2004, the wafer 202 is partially etched with the patterned photoresist layer 541 masking the wafer 202. Where the patterned photoresist layer 541 has been developed and removed, the underlying exposed wafer 202 is etched away. Depending on the etchant selected, the etchant will undercut the patterned photoresist layer 541 or directly copy the shape of the patterned photoresist layer 541. This is illustrated in FIGS. 57A, 57B and 58.

  FIG. 57A shows a cross-sectional view of the silicon wafer of FIG. 55B after performing partial anisotropic etching according to one embodiment of the present invention, and FIG. 57B illustrates anisotropic etching according to another embodiment of the present invention. FIG. 56B shows a cross-sectional view of the silicon wafer of FIG. 56B after changing the process to an isotropic etching process at that location. FIG. 58 shows a cross-sectional view of the silicon wafer of FIG. 56B after performing a partial wet isotropic etch in accordance with one embodiment of the present invention.

  FIG. 57A shows one example where the etchant directly copies the shape of the patterned photoresist layer 541. The etching solution used in this case is an anisotropic reactive ion etching solution (anisotropic RIE). The etched first regions 546A and 546B replicate the shape of the patterned photoresist layer 541. In FIG. 58, a wet isotropic etchant undercuts the developed photoresist layer 541. FIG. 58 illustrates the use of the wet isotropic etch process described in more detail previously with respect to the method illustrated in FIGS. The patterned photoresist layer 541 of FIG. 58 is not affected by this wet isotropic etching process and maintains its original structure (compare with the pre-etched wafer 202 of FIG. 56B).

  FIG. 57B shows the result of a combined anisotropic / isotropic reactive ion etching (RIE) process that forms V-grooves or etched second regions 548A, 548B. In FIG. 57B, etched second regions 548A, 548B are formed by a two-step RIE process. Initially, the wafer 202 is etched under plasma conditions that provide anisotropic etching. As a result, a wafer 202 as shown in FIG. 57A is obtained. The process parameters are then changed at that location so that the etching proceeds isotropically. The RIE isotropic etchant affects the patterned photoresist layer 541, which can be understood by comparing the wafer 202 of FIG. 57B with the wafer 202 of FIGS. 55B and 57A. By carefully choosing the line widths and their relative spacing, the RIE anisotropic portion of the etch can be made to proceed at different rates into the substrate.

  FIG. 58 shows a cross-sectional view of the silicon wafer of FIG. 56B after performing wet isotropic etching. This etch allows the wet isotropic etchant to substantially undercut the patterned photoresist layer 541. Thereby, a shallow V-groove or etched third region 550 is obtained. In any of the etching processes described above (and various combinations thereof), the etching process takes approximately a few tens of microns (of the initial thickness of the wafer 202) to create a suitable groove that will be the cutting edge preform on the finished blade. Only a part).

  Following the step 2004 of etching the wafer 202 using any one of the etching processes (or combinations thereof) described above, in step 2006, the patterned photoresist layer 541 is converted to a suitable wet chemical. (Solvent, commercially available photo stripper, etc.) or ashed in an oxygen plasma apparatus. FIG. 59 shows a cross-sectional view of the wafer of FIG. 57B with the patterned photoresist layer 541 removed. This wafer 202 will provide a single bevel blade. FIG. 60 illustrates a cross-sectional view of the wafer 202 of FIG. 58 with the patterned photoresist layer 541 removed. This wafer 202 will also provide a single bevel blade. FIG. 61 shows the wafer after the patterned photoresist layer 541 has been removed with two partial etches (two etches similar to the etch of FIG. 59) to produce a double bevel blade. FIG. 62 shows a cross-section, and the patterned photoresist layer 541 has been removed with two partial etches (two etches similar to the etch of FIG. 60) to produce a double bevel blade. The cross section of the latter wafer is shown.

  After the patterned photoresist layer 541 is removed in step 2006, in step 2008, the first etched (or grooved) wafer 202 is mounted on UV laser dicing tape, and in step 2010, the wafer is A through slot 390 is cut into 202 to form the non-blade edge of the blade. Both of these steps have been described in more detail above. At step 2012, the attached wafer 202 is removed from the laser tape and sequentially cleaned in a bath to remove debris and organic and metal contaminants. The method 600 then returns to the method described above with respect to FIGS. 1, 2, 3 and 38 and performs an isotropic etch as described in step 1018. There are several additional steps that can be performed to realize additional features. For example, as described above with respect to step 2002, a coating can be applied to one side of wafer 202 prior to isotropic etching step 1018. In addition, an optional dicing step may be performed as described above with respect to step 1016. Following the wet isotropic etch of step 1018, the method proceeds to step 1019 (addition of optional conversion layer) if the method of FIG. 1 is followed, or if the method of FIGS. 2, 3 and 38 is followed. Then, go to step 1020 (attachment).

  In the etching step 1018, the wafer 202 is wet-etched in the above isotropic HNA bath. V-grooves (or etched first, second or third regions 546, 548, 550) are continued by HNA etching to create a very sharp cutting edge, which also etches and removes flat surfaces. The overall wafer / blade thickness is then brought to its final target thickness. The wafer 202 is then transferred to an etch stop where the wafer 202 is thoroughly rinsed. The blade is then singulated and combined with a handle to create a useful mechanical cutting tool (medical sharps) as described in more detail above.

  The invention has been described with reference to several exemplary embodiments. However, it will be apparent to those skilled in the art that the present invention may be embodied in other specific forms than the exemplary embodiments described above. This can be accomplished without departing from the spirit and scope of the present invention. This exemplary embodiment is merely an example and should not be considered limiting.

2 shows a flow chart of a method of manufacturing a double bevel surgical blade in silicon according to a first embodiment of the present invention. Fig. 3 shows a flow chart of a method of manufacturing a single bevel surgical blade with silicon according to a second embodiment of the invention. Figure 5 shows a flow diagram of an alternative method of manufacturing a single bevel surgical blade in silicon according to a third embodiment of the present invention. It is a top view which shows the silicon wafer attached on the mounting assembly. It is a side view which shows the silicon wafer attached on the mounting assembly with the tape. FIG. 2 illustrates the use of a laser water jet to pre-cut a silicon wafer to help machine grooves in the silicon wafer according to one embodiment of the present invention. FIG. 3 shows a dicing saw blade configuration used to machine grooves in a silicon wafer according to one embodiment of the present invention. FIG. 3 shows a dicing saw blade configuration used to machine grooves in a silicon wafer according to one embodiment of the present invention. FIG. 3 shows a dicing saw blade configuration used to machine grooves in a silicon wafer according to one embodiment of the present invention. FIG. 3 shows a dicing saw blade configuration used to machine grooves in a silicon wafer according to one embodiment of the present invention. FIG. 4 illustrates the operation of a dicing saw blade across a silicon wafer mounted on a support backing according to one embodiment of the present invention. Fig. 4 illustrates the use of a slot when machining a groove in a silicon wafer with a dicing saw blade according to one embodiment of the present invention. Fig. 4 illustrates the use of a slot when machining a groove in a silicon wafer with a dicing saw blade according to one embodiment of the present invention. Fig. 4 illustrates the use of a slot when machining a groove in a silicon wafer with a dicing saw blade according to one embodiment of the present invention. FIG. 2 shows a cross-sectional view of a dicing saw blade for machining grooves in a silicon wafer taped according to one embodiment of the present invention. Figure 3 shows a silicon surgical blade having a single bevel cutting edge made in accordance with one embodiment of the present invention. Figure 3 shows a silicon surgical blade having a double bevel cutting edge made in accordance with one embodiment of the present invention. FIG. 2 shows a block diagram of a laser system used to machine grooves in a silicon wafer according to one embodiment of the present invention. 1 shows a block diagram of an ultrasonic machining system used to machine grooves in a silicon wafer according to one embodiment of the present invention. FIG. FIG. 2 shows a diagram of a hot forging system used to form grooves in a silicon wafer according to one embodiment of the present invention. FIG. 4 illustrates a silicon wafer having a single machined groove with a coating applied to the machined surface in accordance with one embodiment of the present invention. FIG. 3 shows a cross-sectional view of a dicing saw blade that machines a second groove in a silicon wafer taped according to one embodiment of the present invention. Figure 3 shows an image of a cross section of a silicon wafer having both sides grooved by machining according to one embodiment of the present invention. 3 illustrates an isotropic etching method performed on a silicon wafer having both sides grooved by machining in accordance with one embodiment of the present invention. 3 illustrates an isotropic etching method performed on a silicon wafer having both sides grooved by machining in accordance with an embodiment of the present invention. FIG. 3 shows an isotropic etching process on a silicon wafer having grooves machined on both sides according to an embodiment of the present invention and a coating layer on one side. Figure 3 shows an isotropic etching method according to another embodiment of the invention on a silicon wafer having machined grooves on both sides and a coating layer on one side. Figure 3 shows the resulting cutting edge of a double bevel silicone surgical blade having a coating on one side made according to an embodiment of the present invention. FIG. 3 shows various examples of surgical blades that can be manufactured according to the method of the present invention. FIG. 3 shows various examples of surgical blades that can be manufactured according to the method of the present invention. FIG. 3 shows various examples of surgical blades that can be manufactured according to the method of the present invention. FIG. 3 shows various examples of surgical blades that can be manufactured according to the method of the present invention. FIG. 3 shows various examples of surgical blades that can be manufactured according to the method of the present invention. FIG. 3 shows various examples of surgical blades that can be manufactured according to the method of the present invention. FIG. 3 shows various examples of surgical blades that can be manufactured according to the method of the present invention. 1 shows a side view at a magnification of 5,000 at the cutting edge of a silicon surgical blade manufactured in accordance with an embodiment of the present invention. FIG. 1 shows a side view of a stainless steel surgical blade made in accordance with one embodiment of the present invention at a magnification of 5,000. FIG. 1 shows a top view of a silicon surgical blade manufactured in accordance with an embodiment of the present invention at a 10,000 × magnification. 1 is a top view of a cutting edge of a stainless steel blade manufactured according to an embodiment of the present invention at a magnification of 10,000 times. FIG. Fig. 4 illustrates an isotropic etching process in a silicon wafer having a groove machined on one side according to another embodiment of the invention and a coating layer on the opposite side. FIG. 6 illustrates an isotropic etching process in a silicon wafer having a groove machined on one side according to another embodiment of the invention and a coating layer on the opposite side. Figure 2 shows a post-slot assembly of a surgical blade and handle manufactured according to one embodiment of the present invention. 1 is a perspective cross-sectional view of a cutting edge made of a crystalline material according to one embodiment of the present invention. FIG. 2 shows a perspective cross-sectional view of a cutting edge made of crystalline material including a layer conversion process according to one embodiment of the present invention. Fig. 4 illustrates the use of a router to machine a linear or non-linear groove in a crystalline material according to one embodiment of the present invention. Fig. 4 illustrates the use of a router to machine a linear or non-linear groove in a crystalline material according to one embodiment of the present invention. Fig. 4 illustrates the use of a router to machine a linear or non-linear groove in a crystalline material according to one embodiment of the present invention. Fig. 4 illustrates the use of a router to machine a linear or non-linear groove in a crystalline material according to one embodiment of the present invention. FIG. 4 shows a flow diagram of a method for routering straight or non-linear grooves in crystalline material according to one embodiment of the present invention. Figure 2 shows a double bevel multiple facet blade manufactured according to one embodiment of the present invention. Figure 2 shows a double bevel multiple facet blade manufactured according to one embodiment of the present invention. Figure 2 shows a double bevel multiple facet blade manufactured according to one embodiment of the present invention. Figure 3 shows a variable double bevel blade manufactured in accordance with one embodiment of the present invention. Figure 3 shows a variable double bevel blade manufactured in accordance with one embodiment of the present invention. Figure 3 shows a variable double bevel blade manufactured in accordance with one embodiment of the present invention. 2 shows an example of several surgical blades manufactured according to the method of the present invention and made available for ophthalmic and other ultra-surgical purposes. 2 shows an example of several surgical blades manufactured according to the method of the present invention and made available for ophthalmic and other ultra-surgical purposes. 2 shows an example of several surgical blades manufactured according to the method of the present invention and made available for ophthalmic and other ultra-surgical purposes. 2 shows an example of several surgical blades manufactured according to the method of the present invention and made available for ophthalmic and other ultra-surgical purposes. Figure 3 illustrates various manufacturing parameters for a surgical blade manufactured in accordance with an embodiment of the present invention. Figure 3 illustrates various manufacturing parameters for a surgical blade manufactured in accordance with an embodiment of the present invention. Figure 3 illustrates various manufacturing parameters for a surgical blade manufactured in accordance with an embodiment of the present invention. Fig. 4 illustrates additional manufacturing parameters for a surgical blade manufactured in accordance with an embodiment of the present invention. Fig. 4 illustrates additional manufacturing parameters for a surgical blade manufactured in accordance with an embodiment of the present invention. FIG. 4 shows a comparison of edge radius ranges for blades made of metal and blade radii made of silicon, in accordance with an embodiment of the present invention. FIG. FIG. 4 shows a comparison of the range of surface roughness of a blade manufactured from metal and the range of surface roughness of a blade manufactured from silicon, according to an embodiment of the present invention. 6 shows a flow diagram of a method for manufacturing a silicon surgical blade according to a fourth embodiment of the present invention. FIG. 39 shows a silicon wafer processed according to the method for manufacturing a silicon surgical blade described in FIG. FIG. 39 shows a silicon wafer processed according to the method for manufacturing a silicon surgical blade described in FIG. FIG. 39 shows a silicon wafer processed according to the method for manufacturing a silicon surgical blade described in FIG. FIG. 39 shows a silicon wafer processed according to the method for manufacturing a silicon surgical blade described in FIG. FIG. 39 shows a silicon wafer processed according to the method for manufacturing a silicon surgical blade described in FIG. The result of etching silicon, which is a plate-shaped specimen of a sample cut by a diamond saw, to various depths is shown with respect to the smoothness of the surface. The result of etching silicon, which is a plate-shaped specimen of a sample cut by a diamond saw, to various depths is shown with respect to the smoothness of the surface. The result of etching silicon, which is a plate-shaped specimen of a sample cut by a diamond saw, to various depths is shown with respect to the smoothness of the surface. The result of etching silicon, which is a plate-shaped specimen of a sample cut by a laser, to various depths is shown with respect to the smoothness of the surface. The result of etching silicon, which is a plate-shaped specimen of a sample cut by a laser, to various depths is shown with respect to the smoothness of the surface. The result of etching silicon, which is a plate-shaped specimen of a sample cut by a laser, to various depths is shown with respect to the smoothness of the surface. The result of etching silicon, which is a plate-shaped specimen of a sample cut by a laser, to various depths is shown with respect to the smoothness of the surface. The result of etching silicon, which is a plate-shaped specimen of a sample cut by a laser, to various depths is shown with respect to the smoothness of the surface. The result of etching silicon, which is a plate-shaped specimen of a sample cut by a laser, to various depths is shown with respect to the smoothness of the surface. FIG. 5 shows the results of comparison between the diamond blade manufactured according to the embodiment of the present invention, the metal blade, and the silicon blade with respect to the peak puncture force. Figure 3 shows the results of a comparison made between a diamond blade, a metal blade and a silicon blade manufactured according to an embodiment of the present invention with respect to the pressure required to cause a flaw tear. Figure 3 shows the comparison results made between a diamond blade, a metal blade and a silicon blade manufactured according to an embodiment of the present invention with respect to the force required to penetrate the test medium. 1 is a cross-sectional view of a wafer having a layer of photoresist material (photoresist) used in manufacturing a surgical blade according to one embodiment of the present invention. FIG. 56 shows a cross-sectional view of the silicon wafer in FIG. 55 with the first patterned photomask disposed on top of the photoresist layer exposed by ultraviolet light. FIG. 55B shows a cross-sectional view of the silicon wafer in FIG. 55A after exposure to ultraviolet light is complete, the photoresist is developed, and the first patterned photomask is removed. FIG. 56 shows an example of a second patterned photomask arrangement similar to the example shown in FIGS. 55A and 55B and exposure with ultraviolet light. FIG. 56 shows an example of a second patterned photomask arrangement and exposure with ultraviolet light similar to the example shown in FIGS. 55A and 55B. FIG. 56 shows a cross-sectional view of the silicon wafer in FIG. 55B after partial anisotropic etching has been performed according to one embodiment of the present invention. FIG. 56B shows a cross-sectional view of the silicon wafer in FIG. 56B after the anisotropic etch process has been changed to an isotropic etch process in its original position in accordance with another embodiment of the present invention. FIG. 56B shows a cross-sectional view of the silicon wafer in FIG. 56B after partial wet isotropic etching has been performed in accordance with another embodiment of the present invention. FIG. 57B shows a cross-sectional view of the wafer in FIG. 57B with the developed photoresist layer removed. FIG. 59 shows a cross-sectional view of the wafer in FIG. 58 with the patterned photoresist layer removed. FIG. 58 shows a cross-sectional view of a wafer with two partial etches similar to the etch process shown in FIGS. 57A and 57B to make a double bevel blade. FIG. 59 shows a cross-sectional view of a wafer with two partial etches similar to the etch in FIG. 58 to produce different types of double bevel blades. 2 shows a flowchart of a method for manufacturing a silicon surgical blade according to one embodiment of the present invention.

Claims (21)

A method of manufacturing a cutting device with a wafer of crystalline material,
Forming a groove including at least one blade profile of a blade on a first surface of the crystalline material in the wafer of the crystalline material;
Etching at least the first surface of the crystalline material to form at least one cutting edge. Further forming at least one side edge of the blade in the crystalline material;
The method of claim 1, wherein the etching of at least the first surface of the crystalline material includes etching the at least one side edge.   The manufacturing method according to claim 2, wherein the at least one side edge includes a non-linear portion.   The manufacturing method according to claim 3, wherein the non-linear portion has a horseshoe shape. The formation of the groove comprises forming a first pattern including a first bevel;
The manufacturing of claim 1, wherein the etching of at least the first surface of the crystalline material comprises etching the first bevel to form at least a first portion of the at least one cutting edge. Method. The forming of the groove comprises forming a second pattern including a second bevel;
6. The method of claim 5, wherein the etching of at least the first surface of the crystalline material includes etching the second bevel to form at least a second portion of a second cutting edge. .   The first pattern and the second pattern are disposed on the first surface of the crystalline material, whereby the first bevel and the second bevel are spaced apart. The manufacturing method according to claim 6.   The manufacturing method according to claim 7, wherein at least one of the first and second patterns includes a plurality of bevels formed in a snowflake pattern on the first surface of the crystalline material.   The manufacturing method according to claim 1, further comprising forming at least one slot including at least a portion of a non-blade edge of the blade in the crystalline material.   The method of claim 9, wherein the forming of the at least one slot includes maximizing a length of the non-blade edge of the blade. The etching step includes
Placing said wafer of crystalline material comprising at least one blade profile on a wafer boat;
Immersing the wafer of crystalline material comprising the wafer boat and at least one blade profile in an isotropic acid bath, and removing the crystalline material evenly on exposed surfaces, thereby providing the at least one blade profile; The manufacturing method according to claim 1, further comprising: uniformly etching the crystalline material such that a sharp cutting device edge having a shape of 1 is etched.   The manufacturing method according to claim 11, wherein the isotropic acid bath contains a mixture of hydrofluoric acid, nitric acid and acetic acid.   The manufacturing method according to claim 11, wherein the isotropic acid bath includes a mixture of hydrofluoric acid, nitric acid, and water. The etching step includes
Placing said wafer of crystalline material comprising at least one blade profile in a wafer boat;
The wafer of crystalline material comprising the wafer boat and at least one blade profile is sprayed with a spray etchant, and the crystalline material on the exposed surface is evenly removed, whereby the at least one blade profile The manufacturing method according to claim 1, further comprising: etching the crystalline material uniformly with the spray etching solution so that a cutting device edge having a sharp shape is etched. The etching step includes
Placing said wafer of crystalline material comprising at least one blade profile on a wafer boat;
The wafer of crystalline material comprising the wafer boat and at least one blade profile is immersed in an isotropic xenon disulfide, sulfur hexafluoride or similar fluorinated gas environment, and the crystalline material on an exposed surface Is removed uniformly so that the sharp cutting device edge in the shape of the at least one blade profile is etched, the crystalline material is removed from the isotropic xenon difluoride, sulfur hexafluoride or The manufacturing method according to claim 1, comprising etching uniformly in a similar fluorinated gas environment. The etching step includes
Placing said wafer of crystalline material comprising at least one blade profile in a wafer boat;
Immersing the wafer of crystalline material comprising the wafer boat and at least one blade profile in an electrolytic bath, and evenly removing the crystalline material on an exposed surface, thereby reducing the shape of the at least one blade profile; The manufacturing method according to claim 1, further comprising etching the crystalline material in the electrolytic bath so that a sharp cutting device edge is etched.   The manufacturing method according to claim 2, wherein the formation of the at least one side edge includes delivering energy to the crystalline material by a laser beam from an excimer laser or a laser water jet.   The manufacturing method according to claim 9, wherein the formation of the at least one slot includes delivering energy to the crystalline material by a laser beam from an excimer laser or a laser water jet.   The manufacturing method according to claim 1, wherein the crystalline material includes silicon. The formation of the groove is
Forming a photoresist layer on the first surface of the crystalline material;
Patterning the photoresist layer, thereby removing at least a portion of the photoresist layer from at least a first portion of the first surface of the crystalline material;
Partially etching the first portion of the first surface of the crystalline material to form the groove, and at least prior to the etching of the first surface of the crystalline material, the photo The manufacturing method according to claim 1, comprising removing the resist layer.   The partial etching may include at least one of isotropic reactive ion etching of the first portion of the crystalline material and anisotropic reactive ion etching of the first portion of the crystalline material. The manufacturing method of Claim 1 containing.

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