^22250 A7 B7 1、發明說明（3) 射中，於下個脈衝前每一脈衝的真正所影響被吹出放電區 外是非常重要的。 所需要的為具有可腐蝕的電極，其不會有害影響氣體 流動且可忍受好幾十億的脈衝而不致有害地影響雷射光 束品質。 本發明提供一種氣體放電雷射具有一雷射室有二長 形之可腐蝕的電極元件，該等氣體放電雷射至少之一具有 大致鈍葉片型部位，包含具有高電力傳導性之材料，有流 線形介電減阻裝置被定位於該鈍葉片型部位之兩側。一脈 衝電力系統以至少ΙΚΗζ之速率提供電氣脈衝。一個吹風 機以至少lQm/s之速度帶動電極間雷射氣體的循環及一熱 交換器被提供以去除被吹風機與放電所產生之熱。 第1圖顯示習知技藝氣體放電雷射之一室的斷面圖。 第2圖顯示該習知技藝雷射之其他特色。 第3圖顯示習知技藝之脈衝電力系統的主要特色。 第4A與4B圖顯示第3圖之脈衝電力系統的電氣脈衝 形狀。 第5圖顯示第09/590,96 1號專利所揭示之陽極總成 的特色。 第6圖為顯示本發明較佳實施例之雷射室的斷面圖。 第7A-D圖顯示較佳的鈍葉片形陽極之圖。 第8A-D圖顯示較佳的介電減阻裝置之圖。 第9 A-C圖顯示較佳的陽極支撐棒之圖。 第10A-E圖顯示較佳的陰極之圖。 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) I I I I ^ « — — — — — — I— · 經濟部智慧財產局員工消費合作社印製 1222250 經濟部智慧財產局員工消費合作社印製 A7 B7_ 五、發明說明（4 ) 第11A-D圖顯示第一較佳的電流回路之圖。 第12A-F圖顯示第二較佳的電流回路之圖。 第13A-C圖顯示額外的葉片電極。 用於提供脈衝電力以在氣體放電雷射內產生放電之 電路石版印刷的主要元件於第3圖中被顯示。該脈衝電力 系統由標準之2 0 8伏特3相電源操作。一個使用整流器 22、反相器24、變壓器26與整流器30之電源將8. 1微法 拉充電電容器Co 42充電至如雷射控制處理器（未畫出）所 引導之約5 0 0至1 20 0伏特間的電壓。當要有一脈衝時， 該雷射控制處理器引導IGBT開關46之關閉，其造成Co 上之能量被放電至該脈衝電力系統之持續部位。Co上之充 電透過感應器48連續地被傳送至電容器排組Ci 52，然後 透過可飽和感應器54及透過電壓變壓器56至電容器排組 Cpm 62，再透過感應器64至尖峰電容器排組CP 82。如第 3圖顯示者，尖峰電容器排組CP與電極84及83以電氣式 並聯地被連接。 第4A圖顯示電容器排組Co，Ci，Cp-i與CP之電位成 為開關42之關閉開始與隨後9微秒之時間的函數。第4B 圖顯示恰在放電前後的800ns之時間片刻。讀者應注意到 該尖峰電容器恰在放電前被充電至約-15,QGGV。此放電持 續約3Gns。在放電之際，電子流動先由上層電極（陰極）84 來至下層的接地電極（陽極）83。電流「過度」充電CP至約 + 6,0 0 0V之正值，此時電子之向下流動在該電子流由下層 接地電極至上層電極後於放電的約15ns之際被逆轉，此 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） ------------裝--------訂--------- (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 1222250 A7 — B7 五、發明說明（5 ) 均在第4B圖中被顯示。 申請人已發現電極腐蝕在二電極均會發生，但接地電 極（陽極83)之腐蝕率約為高電壓電極（陰極84)之四倍。同 時，作業通常會形成氟化金屬之絕緣層非常漸進地在陽極 部位被建立之結果。在某些情形中在接近電極壽命結束 時，被該層覆蓋的放電表面部分可在50%至80%間或更 多。在氟化物層覆蓋的區域中，放電電流穿過小孔，其典 型上趨向具有約50至10 0微米直徑之大致圓形的斷面。 在氟化物層覆蓋的表面不會受到進一步實質腐蝕，但是當 未覆蓋表面區贫減小時，腐蝕率在未覆蓋放電表面被提高 (在小孔的位置之覆蓋表面會出現某些腐蝕）。在習知技藝 雷射建立之電極腐蝕與氟化物典型變得如此嚴重以至於 該雷射光束在約50至100億脈衝不再符合品質規格。 此時，該雷射室典型上以具有新電極之室被替換。更 換室要花費好幾千元且更換需要暫時關閉積體電路生 產。 大多數用於積體電路石版印刷之電氣放電雷射運用 如C3 6 0 0 0銅（6 1. 5 %銅、3 5 · 5 %鋅與3 %鉛）之銅作為電極 材料。很多其他材料已努力被測試以發現較佳的電極材 料。但就申請人之最佳了解而言，在考慮包括雷射製造與 操作成本之所有成本下，沒有一個被證明比銅好。然而， 申請人之最近測試指出由OMG Americas在NC Research Triangle Park的辦公室可購得之註冊商標GLIDCOP®販售 含有次微米A 1 203塊的高強度銅材料是良好的電極材料。 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） r 裝--------訂--------- (請先閱讀背面之注意事項再填寫本頁) 1222250 經濟部智慧財產局員工消費合作社印製 A7 __B7_ 五、發明說明（6 ) 申請人的更近測試指出銅、鉛與鐵合金或銅、鋅、鐵合金 與具有些許鋅與磷之銅、鐵合金可提供改良的績效。這些 測試亦指出電極材料在加工後之韌化亦可改良績效。對陽 極與陰極均為好合金者為C9 5 40 0 ( 8 5 % Cu，11% A1與4% Fe)，而 C19400(97.5%，2·35%Ζη 與 0.03%Ph)對陰極最 好。申請人之一已發現習知如自旋銅合金在氟環境中是很 好的電極材料。很多優異的電極材料與這些室之非常反應 性氟氣不相容。 為了創造良好的雷射反應媒介，在電極間必須創造均 勻的放電電漿。起先在電極間之間隙內的氣體用第1圖顯 示之預先電離器12加以預先電離。當電壓在電極上建立 時，實質部分之電漿在靠近陰極的區域藉由電極材料之離 子濺射被產生。由電極被濺射之金屬原子大多數為蒸氣形 式，且大量部分之金屬原子被電離且在緊密鄰近創造極端 大電場之陰極表面協助形成正離子陰極「下陷」區域，該 電場可導致電子由陰極之流動亦使離開陰極之電子加 速。此過程首先在每一脈衝的第一部位之際施用至陰極 84。然而，由於電極之極性如第4B圖顯示地在脈衝之中 途變換，此效果亦在陽極83發生，其在此時作用成陰極（即 負電極）。在脈衝之際與之後，該等金屬離子可視迅速之 電場狀況被吸引回到電極，但很多與氟之組合藉由循環雷 射氣體而被吹開。申請人已估計出在陽極的腐蝕損失為約 每十億脈衝3公克或每脈衝3X1 (Γ9公克，此對應於約每 脈衝2.8X1Q13原子。由於在陽極上有約15QQmm2之放電表 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） ^ 裝--------訂--------- (請先閱讀背面之注意事項再填寫本頁)^ 22250 A7 B7 1. Description of the invention (3) It is very important that the real influence of each pulse before the next pulse is blown out of the discharge area before the next pulse. What is needed is an electrode that can be corroded, that does not adversely affect gas flow and can tolerate billions of pulses without adversely affecting the quality of the laser beam. The present invention provides a gas discharge laser having a laser chamber with two long erodable electrode elements. At least one of the gas discharge lasers has a generally blunt blade-type portion, and includes a material with high electrical conductivity. Streamlined dielectric drag reduction devices are positioned on both sides of the blunt blade-shaped portion. A pulsed power system provides electrical pulses at a rate of at least 1KZ. A blower drives the circulation of laser gas between the electrodes at a speed of at least lQm / s and a heat exchanger is provided to remove the heat generated by the blower and the discharge. Fig. 1 shows a sectional view of a chamber of a conventional art gas discharge laser. Figure 2 shows other features of this conventional laser. Figure 3 shows the main features of a conventional pulsed power system. Figures 4A and 4B show the electrical pulse shape of the pulsed power system of Figure 3. Figure 5 shows the characteristics of the anode assembly disclosed in the 09 / 590,96 patent. Fig. 6 is a sectional view showing a laser chamber according to a preferred embodiment of the present invention. Figures 7A-D show a diagram of a preferred blunt vane anode. Figures 8A-D show a diagram of a better dielectric drag reduction device. Figures 9 A-C show a diagram of a better anode support rod. Figures 10A-E show diagrams of preferred cathodes. This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling out this page) IIII ^ «— — — — — — I — · Staff of Intellectual Property Bureau, Ministry of Economic Affairs Printed by the Consumer Cooperative 1222250 Printed by the Consumer Property Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7_ 5. Description of Invention (4) Figures 11A-D show the first best current circuit diagram. Figures 12A-F show a diagram of the second preferred current loop. Figures 13A-C show additional blade electrodes. The main elements of a circuit lithograph for supplying pulsed power to generate a discharge within a gas discharge laser are shown in Figure 3. The pulsed power system is operated by a standard 208 volt 3 phase power supply. One uses the power of rectifier 22, inverter 24, transformer 26, and rectifier 30 to charge the 8.1 microfarad charging capacitor Co 42 to about 50 0 to 1 20 as guided by the laser control processor (not shown). Voltage between 0 volts. When there is a pulse, the laser control processor directs the IGBT switch 46 to close, which causes the energy on Co to be discharged to the continuous part of the pulsed power system. The charge on Co is continuously transmitted to the capacitor bank Ci 52 through the inductor 48, and then to the capacitor bank Cpm 62 through the saturable inductor 54 and the voltage transformer 56, and then to the peak capacitor bank CP 82 through the inductor 64. . As shown in FIG. 3, the peak capacitor bank CP and the electrodes 84 and 83 are electrically connected in parallel. Fig. 4A shows that the potentials of the capacitor banks Co, Ci, Cp-i and CP become a function of the start of the closing of the switch 42 and the subsequent time of 9 microseconds. Figure 4B shows a time of 800ns just before and after the discharge. The reader should note that the spike capacitor was charged to approximately -15, QGGV just before discharging. This discharge lasts about 3Gns. When discharging, the electrons flow from the upper electrode (cathode) 84 to the ground electrode (anode) 83 on the lower layer. The current "overcharges" and charges CP to a positive value of about + 6, 0 0 0V. At this time, the downward flow of electrons is reversed after the electron flow from the lower ground electrode to the upper electrode is discharged about 15ns. This paper Standards are applicable to China National Standard (CNS) A4 (210 X 297 mm) ------------ installation -------- order --------- (please Read the notes on the back before filling this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 1222250 A7 — B7 V. The description of the invention (5) is shown in Figure 4B. The applicant has found that electrode corrosion occurs in both electrodes, but the corrosion rate of the ground electrode (anode 83) is about four times that of the high voltage electrode (cathode 84). At the same time, the operation usually results in a very gradual build-up of an insulating layer of metal fluoride at the anode. In some cases, near the end of the electrode life, the portion of the discharge surface covered by this layer may be between 50% and 80% or more. In the area covered by the fluoride layer, the discharge current passes through the pinhole, which typically tends to a generally circular cross section having a diameter of about 50 to 100 microns. The surface covered by the fluoride layer will not be subject to further substantial corrosion, but when the uncovered surface area is reduced, the corrosion rate is increased on the uncovered discharge surface (some corrosion will occur on the covered surface at the location of the pinhole). Electrode corrosion and fluorides established in conventional techniques by lasers typically become so severe that the laser beam no longer meets quality specifications at about 5 to 10 billion pulses. At this point, the laser chamber is typically replaced with a chamber with a new electrode. Changing rooms costs thousands of dollars and replacement requires temporarily shutting down integrated circuit production. Most electrical discharge lasers used for lithography of integrated circuits use copper such as C3 6 0 0 0 copper (6 1.5% copper, 35 · 5% zinc and 3% lead) as the electrode material. Many other materials have been tested to find better electrode materials. However, to the best of the applicant's knowledge, no one has proven to be better than copper, considering all costs including laser manufacturing and operating costs. However, recent tests by the applicant indicate that a high-strength copper material containing sub-micron A 1 203 is a good electrode material sold under the registered trademark GLIDCOP®, which is commercially available from OMG Americas' office in NC Research Triangle Park. This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) r Pack -------- Order --------- (Please read the precautions on the back before filling this Page) 1222250 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 __B7_ V. Description of Invention (6) The applicant's more recent tests indicate that copper, lead and iron alloys or copper, zinc, iron alloys and copper, iron alloys with a little zinc and phosphorus Provides improved performance. These tests also indicate that toughening of electrode materials after processing can also improve performance. C9 5 40 0 (85% Cu, 11% A1 and 4% Fe) are good alloys for both the anode and the cathode, while C19400 (97.5%, 2.35% Zn and 0.03% Ph) is the best for the cathode. One of the applicants has found that conventional copper alloys such as spin copper are good electrode materials in a fluorine environment. Many excellent electrode materials are not compatible with the very reactive fluorine gas of these chambers. In order to create a good laser reaction medium, a uniform discharge plasma must be created between the electrodes. At first, the gas in the gap between the electrodes is pre-ionized using the pre-ionizer 12 shown in Fig. 1. When a voltage is established across the electrode, a substantial portion of the plasma is generated in the area near the cathode by ion sputtering of the electrode material. Most of the metal atoms sputtered by the electrode are in the form of vapor, and a large part of the metal atoms are ionized and help to form a positive ion cathode "sag" region on the surface of the cathode that creates an extremely large electric field in close proximity. This electric field can cause electrons to pass from the cathode. This flow also accelerates electrons leaving the cathode. This process is first applied to the cathode 84 at the first location of each pulse. However, since the polarity of the electrode changes in the middle of the pulse as shown in Fig. 4B, this effect also occurs at the anode 83, which at this time acts as a cathode (ie, a negative electrode). At and after the pulse, these metal ions can be attracted back to the electrode due to the rapid electric field condition, but many combinations with fluorine are blown away by circulating the laser gas. The applicant has estimated that the corrosion loss at the anode is approximately 3 grams per billion pulses or 3X1 (Γ9 grams per pulse, which corresponds to approximately 2.8X1Q13 atoms per pulse. Since there are approximately 15QQmm2 discharge gauges on the anode, the paper size applies China National Standard (CNS) A4 specification (210 X 297 mm) ^ -------- Order --------- (Please read the precautions on the back before filling this page)
$'發明說明（7) 面，此損失約每脈衝每mm2有1. 2 ΧΙΟ 1(1原子。因為銅電極 之每一原子層包含約每mm2有3Χ101()原子，故約2, 500 脈衝陽極會損失一原子層（在2,000Hz脈衝率下比一秒多 一點點）。在100億脈衝後約有4. 4百萬之原子層會損失， 對應於電極放電表面在垂直位置約為0. 5mm。在第1圖顯 示之習知技藝中，此減少伴隨了在電極（特別是陽極）表面 之放電區域的加寬，及在陽極放電表面部位之放電加寬、 放電的移位或分割、及氟化物層之建立。此通常對雷射所 產生之雷射光束的品質具有實質有害的影響。 在對使用含有雷射氣體之氟的電氣放電石版印刷雷 射發展較好的電極中要處理五個重要的議題： (1) 電極腐蝕嚴重地影響光束品質， (2) 電極腐蝕當前限制雷射室壽命， (3) 陽極腐蝕約為陰極腐蝕之四倍， (4) 在陽極上被建立之氟化物層是個問題，以及 (5) 在放電間隙中維持良好的氣體流動狀況是非常重要 的。 此處描述之本發明的各種實施例處理這些議題。該等 電極滿足下列的準則： (1) 該等電極包含腐蝕表面緩慢地在數十億脈衝腐蝕，但此 腐蝕不會實質地影響光束品質。 (2) 該等表面抵抗在放電區域上建立之氟化物絕緣。 (3) 該等電極被設計以提供改良的氣體流動而允許1，0 00Hz 至6, 00 0Hz或以上的重複而不致在該放電區有實質的擾 -10 - 冢紙張尺度適用中國國家標準（CNS)A4規格(210 X 297公釐） ---------丨丨•裝 (請先閱讀背面之注意事項再填寫本頁) ----^ 11111--- *^1^. · 經濟部智慧財產局員工消費合作社印製 經濟部智慧財產局員工消費合作社印製 1222250 A7 B7 五、發明說明（8 ) 動。 第5圖顯示揭示於第09/590,96 1號專利之陽極總成 的橫斷面，該專利為本申請案之來源。可腐蝕的電極72A 與介電流動隔片74A與76A被安裝於陽極支撐棒8GA上。 第6圖為雷射室之斷面圖，顯示申請人所建立及測試 之實際施作。在此室中，一嶄新的電極系統被提供’其比 起第1圖描述之習知技藝的電極系統提供實質改良的壽命 績效。此電極系統之重要的新元件為陽極總成，包含葉片 電極72、介電減阻裝置74與76、陽極支撐棒78 (包含底 座與冷卻翼82)、尖點陰極84及電流回路單元86。 此較佳實施例之陽極72在第7A，7B，7C與7D圖中 被描述。此電極為26.4英吋長及0.939英吋高。其底部 為0.2 84英吋寬及頂端為0. 141英吋寬。第7A圖為斷面 圖、第7B圖為側面圖、第7C圖為底部圖及第7D圖顯示 該電極之頂端的較佳斷面形狀。該斷面形狀為割開的等腰 三角形，具有10度的斜邊及第7A圖顯示之橢圓形頂端。 此斷面形狀亦類似於鈍斧者。該電極之底部被提供26個 相等間隔的斜螺絲孔72A用於將該電極附裝至電極支撐棒 78 〇 較佳的是該陽極材料為以銅為基之合金適合於在氟 氣環境使用之電極。較佳的選擇包括C360()()，C9540 0或 C1 940 0。申請人之測試指出電極在加工後之韌化實質地改 進績效。另一較佳的陽極材料為自旋銅合金，例如可由 Anchor Bronze and Metal 公司在俄亥俄州 Bay Village 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 丨裝--------訂-------— (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 1222250 A7 _B7 五、發明說明（10) 陽極之尖端。 此陰極設計與第1圖顯示之習知技藝間有兩個重要差 別。首先，該陰極之短邊斷面形狀大致為尖點形的而使此 陰極有描述性的名稱，即「尖點陰極」。面向陽極之陰極 的表面為扁平的表面94,以130度之角彼此相逼近。在實 際中點的0. 116英吋部位如第10F圖顯示地被弄圓而成為 橢圓形。在此實施例中有1 5個等距相隔之螺絲孔用於如 第6圖之85顯示地抵住一主絕緣器固定該陰極，並電氣 式地連接該陰極至該雷射系統之高壓脈衝電力。第二個差 別為該陰極之端部段落沿著第1 0E圖顯示之橢圓形路徑斜 進。此形狀比起習知技藝之圓形端部段落可改進電場分 佈。 回流電路86之細節被顯示於第11A，11B，11C與11D 圖。第11A圖顯示回流電路如何由一片0.015英吋厚之鎳 合金（UNS ND 4400)板切割或壓製而成。該回流電路被形 成第11B圖顯示之形狀。肋90為第11C圖顯示之0.09英 吋寬，且G.Q15英吋厚被彎曲，使得該0. 09英吋維度與 氣體流動平行以使流動阻力最小。第11D圖為該回流電路 之一端部的放大圖，顯示該等肋如何被切割以助益上述之 彎曲。一個第二回流電路設計被顯示於第12A-F圖。此設 計為由參照上面第1 2A圖顯示之相同材料雷射切割。第1 2B 圖為第12A圖中於第12B圖段之放大圖。第12C圖與12D 圖為第12B圖中之段的進一步放大。第12E圖為該等肋已 被彎曲成型後之回流電路的底部圖。第12F圖為由放電方 -13 - 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） -^--------^---------. (請先閱讀背面之注意事項再填寫本頁)$ 'Explanation (7) plane, this loss is about 1.2 × ΙΟ 1 (1 atom per mm2 per pulse. Since each atomic layer of the copper electrode contains about 3 × 101 () atoms per mm2, about 2,500 pulses The anode will lose one atomic layer (a little more than one second at a 2,000 Hz pulse rate). After 10 billion pulses, about 4.4 million atomic layers will be lost, corresponding to about 0 of the electrode discharge surface in a vertical position. 5mm. In the conventional technique shown in Figure 1, this reduction is accompanied by the widening of the discharge area on the surface of the electrode (especially the anode), and the widening of the discharge on the surface of the anode discharge, or the displacement or division of the discharge. And the establishment of a fluoride layer. This usually has a substantially detrimental effect on the quality of the laser beam produced by the laser. It is required in electrodes that have a better development of electrical discharge lithography lasers using fluorine containing laser gas Address five important issues: (1) electrode corrosion severely affects beam quality, (2) electrode corrosion currently limits the life of the laser chamber, (3) anodic corrosion is about four times that of cathodic corrosion, and (4) the The fluoride layer is a problem, and (5) It is important to maintain good gas flow conditions in the discharge gap. Various embodiments of the invention described herein address these issues. The electrodes meet the following criteria: (1) The electrodes contain corroded surfaces that are slow Ground corrosion in billions of pulses, but this corrosion does not substantially affect beam quality. (2) The surfaces resist fluoride insulation built up on the discharge area. (3) The electrodes are designed to provide improved gas flow However, it is allowed to repeat from 1,000 Hz to 6,000 Hz or above without causing substantial disturbance in the discharge area. -10-The size of the mound paper applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) --- ------ 丨 丨 • Installation (Please read the precautions on the back before filling out this page) ---- ^ 11111 --- * ^ 1 ^. · Ministry of Economic Affairs, Intellectual Property Bureau, Employee Consumer Cooperatives, Printing Ministry of Economy Printed by the Intellectual Property Bureau's Consumer Cooperative Cooperative 1222250 A7 B7 V. Description of Invention (8) Figure 5 shows the cross section of the anode assembly disclosed in Patent No. 09 / 590,96 No. 1, which is the present application Source: Corrosive electrode 72A and dielectric current separator 74A 76A is installed on the anode support rod 8GA. Figure 6 is a sectional view of the laser chamber, showing the actual implementation built and tested by the applicant. In this chamber, a brand new electrode system is provided. The conventional electrode system described in Figure 1 provides substantially improved life performance. An important new component of this electrode system is the anode assembly, which includes blade electrodes 72, dielectric drag reducing devices 74 and 76, and anode support rods 78 ( It includes a base and a cooling wing 82), a sharp point cathode 84, and a current loop unit 86. The anode 72 of this preferred embodiment is described in Figures 7A, 7B, 7C and 7D. This electrode is 26.4 inches long and 0.939 inches high. Its bottom is 0.284 inches wide and its top is 0.141 inches wide. Figure 7A is a sectional view, Figure 7B is a side view, Figure 7C is a bottom view and Figure 7D shows a preferred sectional shape of the tip of the electrode. The cross-sectional shape is a cut isosceles triangle with a hypotenuse of 10 degrees and an elliptical tip as shown in Fig. 7A. The shape of this section is also similar to that of a blunt axe. The bottom of the electrode is provided with 26 equally spaced oblique screw holes 72A for attaching the electrode to an electrode support rod 78. It is preferable that the anode material is a copper-based alloy suitable for use in a fluorine gas environment. electrode. Preferred options include C360 () (), C9540 0 or C1 9400. The applicant's tests indicate that the toughening of the electrode after processing substantially improves performance. Another preferred anode material is a spin copper alloy. For example, Anchor Bronze and Metal can be used in Bay Village, Ohio. The paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm). ---- Order --------- (Please read the notes on the back before filling out this page) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 1222250 A7 _B7 V. Description of the invention (10) The anode tip. There are two important differences between this cathode design and the conventional technique shown in Figure 1. First, the shape of the short-side cross-section of the cathode is roughly cusp-shaped so that this cathode has a descriptive name, which is "acupoint-point cathode". The surfaces facing the cathode of the anode are flat surfaces 94 that approach each other at an angle of 130 degrees. The 0.1116 inch portion at the actual midpoint is rounded as shown in Figure 10F to become oval. In this embodiment, there are 15 equally spaced screw holes for fixing the cathode against a main insulator as shown in 85 of Fig. 6, and electrically connecting the cathode to the high-voltage pulse of the laser system. electric power. The second difference is that the end section of the cathode is slanted along the elliptical path shown in Figure 10E. This shape improves the electric field distribution compared to the circular end section of the conventional art. Details of the reflow circuit 86 are shown in Figures 11A, 11B, 11C and 11D. Figure 11A shows how the reflow circuit is cut or pressed from a 0.015 inch thick nickel alloy (UNS ND 4400) plate. The reflow circuit is formed in the shape shown in Fig. 11B. The rib 90 is 0.09 inches wide as shown in Figure 11C, and G.Q15 inches is curved so that the 0.09 inch dimension is parallel to the gas flow to minimize flow resistance. Figure 11D is an enlarged view of one of the ends of the reflow circuit, showing how the ribs are cut to aid the aforementioned bending. A second reflow circuit design is shown in Figures 12A-F. This design is laser cut from the same material as shown in Figure 12A above. Figure 12B is an enlarged view of Figure 12A in Figure 12B. Figures 12C and 12D are further enlargements of the segments in Figure 12B. Figure 12E is a bottom view of the reflow circuit after the ribs have been bent. Figure 12F is from the discharging party-13-This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm)-^ -------- ^ ---------. (Please read the notes on the back before filling this page)