200936493 九、發明說明 【發明所屬之技術領域】 本發明係有關於一種用LIGA式技術來製造一金屬微 結構的方法。詳言之，本發明係有關於一種製造一微結構 的方法，該微結構具有一第一金屬製造的核心，其被至少 部份地塗覆一第二金屬的功能性層及其中幾何形狀尺寸的 · 精密度是由該方法直接界定的。本發明亦有關於透過此方 . 法獲得之此類的金屬部件。 © 【先前技術】 由德國Karlsruhe核能硏究中心的W. Ehrfeld在1980 年代所開發之LIGA技術（微光刻電鑄製造）對於製造高精 度金屬微結構而言被證明是有利的。 該LIGA技術的原理在於沈積一光敏樹脂層於一導電 性基材或塗了一導電層的基材上，在於使用一同步加速器 顯影來讓X光穿過一與所想要的微結構的輪廓相符的罩 © 幕，即，藉由物理或化學方式將該光樹脂層未受輻射的部 分去除掉，用以界定一具有該微結構的輪廓之模子，在於 電流沈積一金屬（典型地爲鎳），於該光敏樹脂模子內，然 後移走該模子以獲得該微結構。 所獲得之微結構的品質是可受公評的，但需要使用到 昂貴的是備（同步加速器）則讓此技術無法讓它與必需具有 低單位成本之微結構的大量製造相容。 這就是爲什麼必需在此LIGA方法的基礎上開發出使 -4- 200936493 用UV光敏樹脂之類似的方法。一個此類的方法被 A. B. Frazier等人發表在1993年6月2日出版的 of Microelectromechincal System, Vο 1. 2, Ν deg.中 標題爲 “Metallic Microstructures Fabricated Photosensitive Polyimide Electroplating Molds” 的 . ，其係藉由電鑛金屬於聚亞醯胺基的光敏模子內來 ^ 屬微結構。此方法包括以下的步驟： φ 產生用於後續的電極沈積步驟之一犧牲性金屬 導電性底層； 施用一光敏聚亞醯胺層； 經由一罩幕用UV照射該聚亞醯胺層，該罩幕 要的微結構的輪廓相符； 藉由溶解來顯影該聚亞醯胺層之未被照射的部 得一聚亞醯胺模子； 電流沈積鎳於該模子的開口部分中，直到該模 ❿ 度爲止； 將該犧牲層去除掉並將所獲得之金屬結構與基 來；及 去除掉該聚亞醯胺模子。 依據先前技術的方法所獲得之微結構爲用單一 成的金屬微結構，通常是鎳，及銅，鎳-磷，該金 該金屬微結構打算使用的應用而言並非都是最佳的 上，確實存在一些應用其中這些金屬材料中的一或 於這些應用而言從機械及摩擦觀點來看並不具有最 揭露在 Journal 的一篇 Using 文獻中 製造金 層及一 與所想 分以獲 子的高 材分開 金屬製 屬對於 。實際 多者對 佳的特 -5- 200936493 性。典型地’一有齒的輪子必需要夠堅硬以在受到高應力 時能夠抵抗斷裂，同時亦必需具有低摩擦係數的齒以便於 嚙合。從機械阻力的觀點，選擇鎳是很有利的，但鎳在摩 擦特性上則較不具特性’因爲它具有一相當高的摩擦係數 〇 解決此問題的一個方法包含了藉由LIGA-UV方法用 - 一第一金屬來製造所想要的微結構的核心，然後藉由另外 . 的傳統方法，例如，藉由真空氣相沈積，用一第二金屬層 ◎ 來塗覆該核心。然而，此類的方法具有無法讓部件在可控 制的幾何形狀精密度下被簡單地或得的缺點。 【發明內容】200936493 IX. Description of the Invention [Technical Field of the Invention] The present invention relates to a method of fabricating a metal microstructure using LIGA-type techniques. In particular, the present invention relates to a method of fabricating a microstructure having a core made of a first metal that is at least partially coated with a functional layer of a second metal and geometrical dimensions therein The precision is directly defined by this method. The invention also relates to such metal parts obtained by this method. © [Prior Art] The LIGA technology (microlithography electroforming) developed by W. Ehrfeld of the Karlsruhe Nuclear Energy Research Center in Germany in the 1980s proved to be advantageous for the manufacture of high-precision metal microstructures. The principle of the LIGA technique is to deposit a photosensitive resin layer on a conductive substrate or a substrate coated with a conductive layer by using a synchrotron to develop X-rays through a contour of the desired microstructure. a conforming cover, that is, physically or chemically removing the unirradiated portion of the photo-resin layer to define a mold having the contour of the microstructure, in which a metal (typically nickel) is deposited by current. In the photosensitive resin mold, the mold is then removed to obtain the microstructure. The quality of the microstructure obtained is publicly available, but the need to use expensive (synchronous accelerators) makes this technology incompatible with the large number of fabrications that require microstructures with low unit cost. This is why a similar method of using UV-sensitive resin for -4-200936493 has to be developed on the basis of this LIGA method. One such method is disclosed by AB Frazier et al. in the Microelectromechincal System, Vο 1. 2, Ν deg., entitled "Metallic Microstructures Fabricated Photosensitive Polyimide Electroplating Molds", published on June 2, 1993. The microstructure is derived from an electromineral metal in a polyamidoamine-based photosensitive mold. The method comprises the steps of: φ generating a sacrificial metal conductive underlayer for a subsequent electrodeposition step; applying a photosensitive polyimide layer; irradiating the polyamidamine layer with UV via a mask, the cover The contour of the microstructure is matched; the unilluminated portion of the polyimide layer is developed by dissolution to obtain a polyamidamine mold; current is deposited in the open portion of the mold until the mold degree The sacrificial layer is removed and the obtained metal structure is bonded to the base; and the polyamidamine mold is removed. The microstructure obtained according to the prior art method is a single metal microstructure, typically nickel, and copper, nickel-phosphorus, which is not optimal for the intended use of the metal microstructure. There are some applications in which one of these metallic materials or, for these applications, does not have the most exposed in the Journal of the Journal from the mechanical and frictional point of view, the gold layer is created and the desired one is obtained. High-quality metal is separate. Actually many of them are good -5-200936493 sex. Typically, a toothed wheel must be rigid enough to resist fracture when subjected to high stresses, and must also have teeth with a low coefficient of friction to facilitate engagement. From the viewpoint of mechanical resistance, it is advantageous to select nickel, but nickel is less characteristic in terms of friction characteristics because it has a relatively high coefficient of friction. One method for solving this problem involves using the LIGA-UV method. - a first metal to make the core of the desired microstructure, and then coating the core with a second metal layer ◎ by another conventional method, for example, by vacuum vapor deposition. However, such methods have the disadvantage of not allowing the component to be simply obtained under controllable geometric precision. [Summary of the Invention]
本發明的一個目的是要藉由提供一種用來製造微結構 的方法來克服前述的缺點以及其它的缺點，這些微結構從 它們的成分的觀點來看可被更佳地改造以適合它們將被使 用的應用。如此地獲得的這些微結構具有精密度在控制中 G 的幾何形狀尺寸。 本發明的另一個目的爲提供此種類方法的一個方法， 它所製造的微結構具有一第一金屬製造的核心，其被至少 部份地塗覆一第二金屬的功能性層，及其中幾何形狀尺寸 的精密度是由該方法直接界定的。 本發明的另一個目的爲提供此種類方法的一個方法， 它實施上很簡單且很便宜。 因此，本發明係有關於一種製造一金屬微結構的方法 -6- 200936493 ，其包含的步驟爲： a) 取得一基材，其具有至少一導電表面； b) 施用一光敏樹脂層至該基材的該導電表面； c) 經由一罩幕照射該樹脂層，該罩幕界定該所想要的 微結構的輪廓； d) 將該光敏樹脂層之未被照射的區域溶解用以曝露出 在這些地方之該基材的導電表面； e) 電流地且均勻地從該基材的導電表面及該光敏樹脂 的一導電表面沈積一第一金屬； f) 電流地且均均地從該第一金屬層沈積一第二金屬層 以形成一塊體，該塊體幾乎到達該光敏樹脂層的頂面的高 度； g) 將該樹脂與該被沈積的金屬弄平用以讓該樹脂與該 被電極沈積的塊體在同一水平 h) 藉由層剝（delamination)來將該樹脂層及該電極沈 積的塊體與該基材分開； i) 將該光敏樹脂層從該被層剝的結構上去除掉，以釋 放出被如此地形成的該微結構。 此方法讓完工的部件具有一第一金屬製成的核心，塗 覆一層第二金屬，及其中該等幾何形狀尺寸之所想要的精 密度是由該光敏樹脂模子（這兩種金屬的電流沈積發生在 此模子內）的尺寸來界定，或換言之，是由所使用之光刻 技術的精密度來決定。謹慎地選擇形成該微結構的兩種金 屬可讓該部件的機械特性針對一給定的應用被最佳地改造 200936493 。例如，如果一有齒的輪子將被製造的話，該第一金屬可 以一纖細的層的形式被沈積，典型地爲一層數十微米後的 鎳-磷層以降低該部件的摩擦係數，且該第二金屬可以一 鎳塊體的形式被沈積，其可給予該部件機械的阻力。 依據本發明的一較佳的實施例，該第一的第二金屬具 有不同的機械特性，以形成一機械特性被最佳化的微結構 - 。該第一金屬較佳地具有比該第二金屬低的摩擦係數，且 . 該第二金屬具有比該第一金屬高的機械阻力。該第一金屬 @ ，例如，是一鎳-磷合金及該第二金靥是，例如，鎳》 典型地，該基材的導電表面是由一疊鉻與金的層所形 成的且該光敏樹脂層的導電表面係藉由活化該樹脂來形成 的。 此方法可製造數個微機械結構在同一基材上。 依據本發明的另一實施例，該方法更包含在步驟h) 之前的一沈積一導電的底層及用一第二罩幕重復步驟b) 至g)的步驟，該第二罩幕界定一用於該微結構的一第二 〇 層的第二輪廓，例如，用以製造一有齒的輪子，其具有兩 個不同直徑的齒狀物（toothing)。 本發明的方法對於製造用於時計運動之微結構部件而 言是特別有利的。詳言之，該等部分可選自於包含有齒的 輪，擒縱輪，槓桿，樞轉部件，跳簧，平衡簧，凸輪及被 動部件的組群中。 【實施方式】 -8- 200936493 使用在依據本發明的方法的步驟a)中的基材1是例如 用矽，玻璃或陶瓷晶圓形成的，一導電的底層被蒸汽沈積 在該基材上，即一個能夠觸發電鑄反應的層。該導電的底 層典型地是由一鉻次層2與一金層3所形成的（圖1)。 或者，該基材可用不銹鋼或其它能夠觸發該電鑄反應 . 的金屬來形成。在不銹鋼基材的例子中，該基材將首先被 清潔。 φ 使用在依據本發明的方法的步驟b)中的光敏樹脂4 較佳地爲可從Shell Chemical公司的品號SU-8獲得之八 官能基（octofunctional)環氧樹脂及一選自於三芳基流鹽之 光起始劑，如描述於美國專利第4,05 8,401號中者。此樹 脂在UV照射的作用下可被光聚合化（photopolymised)。 應被注要的是，一被證明適合此樹脂的溶劑爲r-丁內酯 (GBL)。 或者’在有一 DNQ(DiazoNaphtoQuinone)光起始劑存 Q 在下’酚醛型酚甲醛基樹脂亦可被使用。 樹脂4可用任何適當的機構，譬如使用一旋轉塗佈機 ，沈積在基材1上直到達到所想要的厚度爲止。典型地， 該樹脂的厚度在150微米至1公釐之間。根據所想要的厚 度及所用的沈積技術，樹脂4將會在一或數次中被沈積。 樹脂4然後被加熱到9 0至9 5。(：之間一段時間（其與 被沈積的厚度有關）用以去除掉該溶劑。 如圖3所示’下一個步驟幻係關於用uv輻射透過一 罩幕來照射該樹脂層’該罩幕界定所想要的微結構Μ的 -9- 200936493 輪廓及被隔絕的區域4a與未被隔絕的區域4b。此UV輻 射典型地在200至1 000mJ_cm_2，沿著3 65奈米波長測量 ，這與該層的厚度有關。如果有需要的話，一退火步驟可 對該層實施以完成由該UV輻射所誘發之光聚合化作用。 此退火步驟較佳地是在9 0°C至95°C之間被實施達30分鐘 的時間。該等被隔絕的區域4a(被光聚合化的區域）變成對 . 溶劑不敏感。然而，一溶劑可隨後溶解該未被隔絕的區域 . 。 Ο 如圖4所示，下一個步驟d)將該光敏樹脂層之未被 隔絕的區域4b顯影用以曝露出在該等區域下之基材1的 導電層3。此操作係藉由使用一選自於GBL( 7* -丁內酯）與 PGME A(醋酸丙二醇甲酯醚）的溶劑來溶解未被隔絕的區域 4B來實施。一具有該金屬微結構的輪廓之被隔絕的光敏 樹脂模子4a可被製造出來。 如圖5所示，下一個步驟e)包含從該導電層3開始起 將一第一金屬的層5電流沈積至該模子中，該第一層只延 © 伸至該模子的深度的一部分且亦沿著該模子的垂直壁延伸 。爲了要如此作，形成該模子的該樹脂層4已被活化用以 讓它導電或被塗覆一導電的底層。此第一金屬的層5的厚 度與人想要獲得之該微結構的披覆層的厚度相當。典型地 ，此層的厚度介於數微米至數十微米之間。 如圖6所示的下一個步驟f)包含電流沈積一不同於該 第一金屬之第二金屬的層6於該塗覆了該層5的模子中， 用以形成一幾乎到達該光敏樹脂4a的頂面的塊體，該塊 -10- 200936493 體是由該第一金屬的層5及該第二金屬的層6所形成的。 在本文中，“金屬”很自然地亦包括金屬合金。該第一與 第二金屬典型地選自於包括鎳，銅，金或銀，及金-銅， 鎳-鈷，鎳-鐵，及鎳-磷等合金的組群中。 該第二金屬的層6的厚度根據該微結構Μ的目的用 途而改變。典型地，該第二金屬的層6的厚度可變化於1 至100微米之間。在一特殊的應用中，譬如像是一凸輪或 小齒輪，吾人可例如製造一微結構其包括具有良好摩擦特 性的層5，其典型地由鎳-磷合金製成，及一典型地爲鎳 之第二金屬的層6，其是有機械阻力的。 電鑄條件，特別是用於將被電極沈積之每一金屬或合 金之電鑄浴的成分，該系統的幾何形狀，電壓及電流密度 ，依據電鑄領域中已知的技術加以選擇（例如，由設在美 國紐約之Van Nostrand Reinhold有限公司於1 984年出版 之由Di Bari G.A·所著“電鑄”電鍍手冊第4版）。 在圖7所示的下一個步驟g)中，該被電鑄的塊體被 做成與該樹脂層齊平。此步驟可藉由硏磨及拋光來實施， 用以立即提供具有平的頂面之的微結構，其具有與手錶工 業用來製造範圍運動件（ranger movement)的表面的要求相 容之表面皺紋狀態。 如圖8所示的下一個步驟h)包含藉由層剝（delamination) 將該樹脂層及該被電極沈積的塊體從該基材上剝下來。當 該層剝作業被實施時，該光敏樹脂層從該被層剝下來的結 構上被去除掉用以釋放出被形成的微結構M。爲了要如此 -11 - 200936493 作，該被光聚合化的樹脂在步驟h)中被N-甲基-2-吡咯酮 (NMP)溶解，或該樹脂可用電漿蝕刻來將其去除掉。 如此被釋放出來的微結構可立即被使用，或如所需地 在適當的加工後被使用。很清楚的是，因爲樹脂模子4的 幾何形狀精密度的關係，示於圖8中之微結構Μ包括一 由該第二金屬層6形成之核心及一由該第一金屬層5形成 - 之極精密的披覆層。因此，如圖8所示，吾人可獲得一微 t 結構，它的外部’內部及底壁都被塗覆該第一金屬層5。 ❹ 因此，如上文中所解釋的，如果第一金屬層5具有良 好的摩擦品質的話，這些壁可有利地在前述的應用中，譬 如像是一凸輪或一小齒輪中，作爲一接觸表面。 【圖式簡單說明】 本發明的其它特徵與優點從下面一依據本發明的方法 的示範性實施例之配合附圖的詳細描述中將會更爲清楚， 此實施例純粹是爲了舉例而被提供，其中： © 圖1至8顯示本發明之用來製造一有齒的輪子的方法 的實施例的步驟。 【主要元件符號說明】 1 :基材 2 :鉻次層 3 :金層 4 :光敏樹脂 -12- 200936493 4 a :被隔絕的區域 4b:未被隔絕的區域 5 :第一金屬層 6 :第二金屬層 Μ :微結構It is an object of the present invention to overcome the aforementioned shortcomings and other disadvantages by providing a method for fabricating microstructures that can be better modified from the point of view of their composition to suit that they will be The application used. The microstructures thus obtained have the geometrical dimensions of precision in control G. Another object of the present invention is to provide a method of the method of the present invention, which fabricates a microstructure having a core made of a first metal that is at least partially coated with a functional layer of a second metal, and geometry thereof The precision of the shape size is directly defined by the method. Another object of the invention is to provide a method of this type of method which is simple and inexpensive to implement. Accordingly, the present invention is directed to a method of making a metal microstructure-6-200936493 comprising the steps of: a) obtaining a substrate having at least one electrically conductive surface; b) applying a photosensitive resin layer to the substrate The conductive surface of the material; c) illuminating the resin layer via a mask that defines the contour of the desired microstructure; d) dissolving the unirradiated region of the photosensitive resin layer for exposure a conductive surface of the substrate at these locations; e) galvanically and uniformly depositing a first metal from the conductive surface of the substrate and a conductive surface of the photosensitive resin; f) galvanically and uniformly from the first Depositing a second metal layer to form a body, the block reaching a height of a top surface of the photosensitive resin layer; g) flattening the resin and the deposited metal for the resin and the electrode to be electrode The deposited block is separated from the substrate by delamination at the same level h) by delamination; i) removing the photosensitive resin layer from the layered structure Drop to release it so Into the microstructures. The method allows the finished part to have a core made of a first metal, coated with a second layer of metal, and the desired precision of the geometric dimensions of the material is determined by the photosensitive resin mold (the current of the two metals) The size of the deposition occurring within the mold is defined, or in other words, determined by the precision of the lithographic technique used. Careful selection of the two metals that form the microstructure allows the mechanical properties of the part to be optimally modified for a given application 200936493. For example, if a toothed wheel is to be fabricated, the first metal can be deposited in the form of a fine layer, typically a layer of tens of microns of nickel-phosphorus to reduce the coefficient of friction of the component, and The second metal can be deposited in the form of a nickel block that imparts mechanical resistance to the component. In accordance with a preferred embodiment of the present invention, the first second metal has different mechanical properties to form a microstructure that is optimized for mechanical properties. The first metal preferably has a lower coefficient of friction than the second metal, and the second metal has a higher mechanical resistance than the first metal. The first metal @, for example, is a nickel-phosphorus alloy and the second metal is, for example, nickel. Typically, the conductive surface of the substrate is formed by a stack of layers of chrome and gold and the photosensitive The conductive surface of the resin layer is formed by activating the resin. This method allows the fabrication of several micromechanical structures on the same substrate. According to another embodiment of the present invention, the method further comprises the steps of depositing a conductive underlayer before step h) and repeating steps b) to g) with a second mask, the second mask defining a A second contour of a second layer of the microstructure, for example, is used to make a toothed wheel having two different diameters of toothing. The method of the present invention is particularly advantageous for the manufacture of microstructured components for timepiece motion. In particular, the portions may be selected from the group consisting of a toothed wheel, an escape wheel, a lever, a pivoting member, a jumper spring, a balance spring, a cam and a driven member. [Embodiment] -8- 200936493 The substrate 1 used in step a) of the method according to the invention is formed, for example, from a crucible, glass or ceramic wafer, and a conductive underlayer is vapor deposited on the substrate, That is, a layer that can trigger an electroforming reaction. The electrically conductive bottom layer is typically formed from a chrome sublayer 2 and a gold layer 3 (Fig. 1). Alternatively, the substrate can be formed from stainless steel or other metal capable of triggering the electroforming reaction. In the case of a stainless steel substrate, the substrate will be cleaned first. φ The photosensitive resin 4 used in the step b) of the method according to the invention is preferably an octofunctional epoxy resin obtainable from Shell Chemical Company's product number SU-8 and one selected from the triaryl group. A salt-based photoinitiator, as described in U.S. Patent No. 4,05,401. This resin can be photopolymised by the action of UV irradiation. It should be noted that a solvent proven to be suitable for this resin is r-butyrolactone (GBL). Alternatively, a phenolic phenol formaldehyde-based resin may also be used in the presence of a DNQ (DiazoNaphtoQuinone) photoinitiator. Resin 4 can be deposited on substrate 1 using any suitable mechanism, such as using a spin coater, until the desired thickness is achieved. Typically, the resin has a thickness between 150 microns and 1 mm. The resin 4 will be deposited in one or several times depending on the desired thickness and the deposition technique used. The resin 4 is then heated to 90 to 95. (: a period of time (which is related to the thickness to be deposited) to remove the solvent. As shown in Fig. 3, 'the next step is about irradiating the resin layer with a uv radiation through a mask.' Defining the desired microstructure Μ-9-200936493 profile and isolated area 4a with unisolated area 4b. This UV radiation is typically measured at 200 to 1 000 mJ_cm_2 along a wavelength of 3 65 nm, which is The thickness of the layer is related. If desired, an annealing step can be performed on the layer to effect photopolymerization induced by the UV radiation. The annealing step is preferably at 90 ° C to 95 ° C. The time is between 30 minutes. The isolated areas 4a (photopolymerized areas) become insensitive to solvent. However, a solvent can then dissolve the unisolated areas. Ο Figure 4 As shown, the next step d) develops the uninsulated regions 4b of the photosensitive resin layer to expose the conductive layer 3 of the substrate 1 under the regions. This operation is carried out by dissolving a non-isolated region 4B using a solvent selected from GBL (7*-butyrolactone) and PGME A (propylene glycol methyl ether ether). An isolated photosensitive resin mold 4a having the outline of the metal microstructure can be manufactured. As shown in FIG. 5, the next step e) comprises galvanically depositing a layer 5 of a first metal into the mold starting from the conductive layer 3, the first layer extending only to a portion of the depth of the mold and It also extends along the vertical wall of the mold. In order to do so, the resin layer 4 forming the mold has been activated to make it conductive or coated with a conductive underlayer. The thickness of the layer 5 of this first metal is comparable to the thickness of the cladding layer of the microstructure that the person wants to obtain. Typically, the thickness of this layer is between a few microns and tens of microns. The next step f) shown in Figure 6 comprises galvanically depositing a layer 6 of a second metal different from the first metal in the mold to which the layer 5 is applied to form an almost reaching the photosensitive resin 4a. The top block, the block-10-200936493 body is formed by the layer 5 of the first metal and the layer 6 of the second metal. As used herein, "metal" naturally also includes metal alloys. The first and second metals are typically selected from the group consisting of nickel, copper, gold or silver, and alloys of gold-copper, nickel-cobalt, nickel-iron, and nickel-phosphorus. The thickness of the layer 6 of the second metal varies depending on the intended use of the microstructure. Typically, the thickness of the layer 6 of the second metal can vary from 1 to 100 microns. In a particular application, such as a cam or pinion, we may, for example, fabricate a microstructure comprising a layer 5 having good friction characteristics, typically made of a nickel-phosphorus alloy, and typically a nickel The second metal layer 6, which is mechanically resistant. Electroforming conditions, particularly the composition of the electroforming bath for each metal or alloy to be deposited by the electrode, the geometry, voltage and current density of the system are selected according to techniques known in the art of electroforming (for example, The "Electroforming" Electroplating Handbook, 4th Edition, by Di Bari GA, published by Van Nostrand Reinhold Co., Ltd., New York, USA, in 1984. In the next step g) shown in Fig. 7, the electroformed block is made flush with the resin layer. This step can be carried out by honing and polishing to immediately provide a microstructure with a flat top surface that has surface wrinkles that are compatible with the requirements of the watch industry for manufacturing a range of ranger movements. status. The next step h) shown in Figure 8 comprises stripping the resin layer and the electrode-deposited block from the substrate by delamination. When the layering operation is carried out, the photosensitive resin layer is removed from the layer peeled off to release the formed microstructure M. To be so -11 - 200936493, the photopolymerized resin is dissolved in N-methyl-2-pyrrolidone (NMP) in step h), or the resin can be removed by plasma etching. The microstructure thus released can be used immediately or, if desired, after proper processing. It is clear that the microstructure 示 shown in FIG. 8 includes a core formed by the second metal layer 6 and a layer formed by the first metal layer 5 because of the geometric precision of the resin mold 4. Extremely precise coating. Therefore, as shown in Fig. 8, we can obtain a micro-t structure in which the outer 'inner and inner walls are coated with the first metal layer 5. ❹ Therefore, as explained above, if the first metal layer 5 has a good frictional quality, the walls may advantageously be used as a contact surface in the aforementioned applications, such as, for example, a cam or a pinion. BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the present invention will become more apparent from the following detailed description of exemplary embodiments of the present invention, , wherein: Figures 1 through 8 show the steps of an embodiment of the method of the invention for making a toothed wheel. [Main component symbol description] 1 : Substrate 2 : Chromium sublayer 3 : Gold layer 4 : Photosensitive resin -12 - 200936493 4 a : Isolated region 4b: Unisolated region 5 : First metal layer 6 : Two metal layer Μ: microstructure
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