TW553920B - Dielectric composition for multi-layers ceramics capacitor - Google Patents

Dielectric composition for multi-layers ceramics capacitor Download PDF

Info

Publication number
TW553920B
TW553920B TW91101639A TW91101639A TW553920B TW 553920 B TW553920 B TW 553920B TW 91101639 A TW91101639 A TW 91101639A TW 91101639 A TW91101639 A TW 91101639A TW 553920 B TW553920 B TW 553920B
Authority
TW
Taiwan
Prior art keywords
composition
dielectric
dielectric composition
sintering
mol
Prior art date
Application number
TW91101639A
Other languages
Chinese (zh)
Inventor
Akira Sawasaki
Chiho Morita
Kiyotaka Saito
Original Assignee
Eagle Advanced Ceramics Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eagle Advanced Ceramics Corp filed Critical Eagle Advanced Ceramics Corp
Priority to TW91101639A priority Critical patent/TW553920B/en
Application granted granted Critical
Publication of TW553920B publication Critical patent/TW553920B/en

Links

Landscapes

  • Ceramic Capacitors (AREA)
  • Inorganic Insulating Materials (AREA)

Abstract

A dielectric composition for a multi-layer ceramic capacitor will not become a semiconductor during a reduction sintering process and has a high dielectric constant. The composition is a Ti-Ba-based composition of the following formula: (Bal-x-y-zCaxYyYbz)n(Til-a-b-c-dZraMnbNbcMOd)O3+delta, in which 0 < x < 0.15, 0 < y+z < 0.02, 0.25 < y/z < 4.00, 0 < a < 0.35, 0 < b < 0.05, 0 < c+d < 0.01, 1.0 < c/d < 9.0, 1.0 < n < 1.05, delta is the deviation of a combined oxygen atom. The composition is characterized in that the barium molecular group contains a tiny amount of yttrium and ytterbium, and the titanium molecular group contains a tiny amount of molybdenum and niobium. During the sintering process, a specific amount of a copper silicone oxide is used as a sintering agent.

Description

553920 A7 五 、發明說明( B7 組成本關於一種具高介電常數之陶究電容器之介電 χ 将別是一種鋇分子團中合右料Θ 子團中于图中3有微Ϊ之紀鏡金屬,鈦原 介電組成在燒結同時,本發明的 :目:;到燒結出之陶擔器介電組成具有高介電常數 (b二多Λ陶究電容器之製作’其係先以-鈦酸鎖基 =:V:1製成一介電片體,然後將作為内電極之 介電片體it電片體之表面’接著在將此帶有電極之 片體隹璺成塊,以空氣在1250_1300 t下轨處理_ 二”内電極之介電質電容器,最後,將:電° 电極結合而成為一最終之多層陶瓷電容器。 線 從上述可知,内電極需與介電材料一起燒結,因此内 '極的材料須具備有高融點、高溫氧化狀態下不會氧化和 ί介電材料間不會有反應的性質。惰性金屬如始::= 專之合金可滿足這些要求而f被用來作為内電極之材料。 經濟部智慧財產局員工消費合作社印製 ^然這些材料有極佳之特性,另一方面它們的價位也 心貝’因此’内電極材料之成本往往占有多層陶究電容 器製作成本之50%以上’為增加多層陶究電容器製 之最大因素。 價格便宜的卑金屬中如錄、鐵、始、鶴、錮等同樣具 有高融點的特性’但這些皁金屬在高溫氧化氣氛下容易被 氧化,之後隨及無法作為電極,因此卑金屬作電極需要在 中性或還原性之氣氛下作燒結才能作為多層陶瓷電容器之 3553920 A7 V. Description of the invention (Group B7 costs about the dielectric of a ceramic capacitor with a high dielectric constant χ will be a kind of barium molecular group in which the right material Θ subgroup is shown in Figure 3 At the same time as the sintering of the original dielectric composition of metal and titanium, the purpose of the present invention is: the dielectric composition of the ceramic carrier to the sintering has a high dielectric constant (b. An acid-locked base =: V: 1 is made into a dielectric sheet, and then the dielectric sheet as an internal electrode is formed on the surface of the sheet. In the 1250_1300 t lower rail processing_ two ”internal electrode dielectric capacitor, finally, the combination of: electric ° electrode into a final multilayer ceramic capacitor. From the above, we know that the internal electrode needs to be sintered with the dielectric material. Therefore, the material of the inner pole must have the properties of high melting point, no oxidation under high temperature oxidation state, and no reaction between dielectric materials. Inert metals such as: == special alloys can meet these requirements and f is Used as a material for internal electrodes. These materials have excellent characteristics. On the other hand, their prices are also high. Therefore, the cost of internal electrode materials often accounts for more than 50% of the manufacturing cost of multilayer ceramic capacitors. The most important factor is the low-priced base metals such as Lu, Iron, Shi, Crane, and Rhenium, which also have high melting point characteristics. But these soap metals are easily oxidized in a high-temperature oxidizing atmosphere, and cannot be used as electrodes afterwards. Therefore, base metals used as electrodes need to be sintered in a neutral or reducing atmosphere to be used as multilayer ceramic capacitors.

本紙張尺度適用中國國家標準(CNS)A4規格(210 X 297公爱) 五、發明說明(2 ) 内電極。然而使用卑金屬的另一個問題是,卑金屬雖然在 還原或中性氣氛下燒結可成為電極,但卻有半導化的情形 赉生’針對這個問題’若將介電質組成BaTiQ3中之Ba/Ti 比例調整為大於一時即可克服此缺點,藉此我們可以以較 低價之卑金屬如鎳、銅等作為多層陶瓷電容器之内電極以 降低製作成本提高競爭力。 隨著3 C產業蓬勃發展,電子元件市場之需求亦隨著 心速成長小型化、而性能及低成本為製作陶兗電容器之 發展驅勢,主要提高電容器容量為使用高介電常數之介電 材質或讓介電片體厚度變薄,但是高介電常數的介電材 料,其組成晶粒過大會使每單層所擁有之晶粒數目下降, 例如介電層片體之厚度下降至1 0 以下,陶瓷電容器 之可靠度隨即劇烈性地下降。 ° .另一方面,已知添加微量之金屬氧化物燒結劑到 BaTi〇3中,可以燒結出之有小晶粒之無還原介電質陶瓷, 但添加微量之金屬氧化物無法讓燒結之介電質組成達到高 介電常數,並傾向於在燒結中被還原。因此除了介電組: j身的成份外,就現階段之多層陶瓷電容器製作技術而 吕/,仍存在有極待解決及克服的問題。 κ ^緣是,本案發明人針對前述之多層陶瓷電容器之介 電組成,再深入加以積極研究改進之道,經長期之;丨 作而開發出本發明。 贫力 言式This paper size applies to China National Standard (CNS) A4 specification (210 X 297 public love). 5. Description of the invention (2) Internal electrode. However, another problem with base metals is that although base metals can be used as electrodes when sintered in a reducing or neutral atmosphere, there is a case of semiconductivity. For this problem, if the dielectric is composed of Ba in BaTiQ3, Adjusting the / Ti ratio to be greater than one time can overcome this disadvantage, so that we can use lower-priced base metals such as nickel and copper as the internal electrodes of the multilayer ceramic capacitors to reduce the manufacturing cost and increase competitiveness. With the rapid development of the 3 C industry, the demand for the electronic component market has also grown with the rapid development of miniaturization, and performance and low cost are the driving forces for the development of ceramic capacitors. The main improvement of capacitor capacity is the use of high dielectric constant dielectrics. The material may make the thickness of the dielectric sheet thin, but the composition of the high-constant dielectric material is too large to reduce the number of grains per single layer. For example, the thickness of the dielectric sheet is reduced to 1 Below 0, the reliability of ceramic capacitors drops sharply. ° On the other hand, it is known that adding a small amount of metal oxide sintering agent to BaTi03 can sinter a small-grain non-reduction dielectric ceramic, but adding a small amount of metal oxide cannot make the sintered medium The dielectric composition reaches a high dielectric constant and tends to be reduced during sintering. Therefore, in addition to the composition of the dielectric group, there are still problems that need to be solved and overcome regarding the current multilayer ceramic capacitor manufacturing technology. κ ^ is because the inventors of the present case have made intensive research and improvement on the dielectric composition of the aforementioned multilayer ceramic capacitors, and have developed the present invention over a long period of time. Poor speech

本紙張尺度適用中國國家標準(cns)A4規 x 297公釐)This paper size applies the Chinese National Standard (cns) A4 regulations x 297 mm)

、發明說明(3 瓷雷一'仍擁有鬲介電常數之介電組成,以縮小多層陶 文電谷益之體積。 2、丨述之發明目的,本發明中所使用之技術手段 為使用如下之燒結介電組成: (Bah,zCaxYyYbz)n(Ti ^—dZrJiibNbcMocOOw 其巾 〇&lt; X &lt;0.15 〇&lt; y + ζ &lt; 〇. 〇2 0.25&lt;y/z&lt;4. 00 〇&lt; a&lt; 0. 35 〇&lt; b&lt; 0. 05 〇&lt; c+d&lt; 0· 01 1· 〇&lt;c/d&lt; 9· 0 1.0&lt;n&lt;1.05 5為結合氧原子之偏差值 汶陶瓷電谷器之介電組成其特徵在於:此介電 組成在鋇分子團中含有微量之紀鏡金屬,鈦原子團中 具有微ϊ之鈮鉬金屬,另外在燒結過程中另外添加銅 矽氧化物作為燒結劑。 為使貴審查委員能進一步瞭解本發明之原理及功 效,玆舉以下之操作實施例及分析實驗: 先準備純度大於99·8%之燒結原料BaC〇3、CaC〇3、〜 Y2〇3、Yb2〇3、Ti〇2、Zr〇2、MnO、Nb2〇5、Mo〇3、CuO、Si〇2, 本紙張尺度適用中國國家標準(CNS)A4規格⑽x 297公杂·· (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 X 消 費 合 作 社 印 製 553920A7_ -- _B7__ . ,^^ 五、發明說明(^ ) 並選擇性添加銅、矽的氧化物,如CuO、Si〇2作為燒結 劑,將燒結原料以混合結塊成(Bam-zCaxYJbzMTi卜a-b_c_ dZraMnbNbcM〇d)〇3+5 之介電組成粗胚,其中 x、y、z、n、a、 b、c之數值須符合下表一 : · 經濟部智慧財產局員工消費合作社印製 樣 主 要成份組成 添加劑 本 (Bs 1 -χ-y-z C&lt; axYyYbz)n(T i 1-a-b-c-d ZraMnbNbcM〇d)〇3+ δ X Y Z η A B C d CuO Si〇2 1 * 0. 000 0.00250 0.00250 1.0070 0. 20 0.0050 0.00175 0.00075 _ - 2 * 0. 050 0.00000 0.00000 1.0050 0. 20 0.0050 0.00175 0.00075 一 - 3 * 0. 050 0.00100 0.00400 1.0070 0. 20 0.0050 0.00175 0.00075 一 • 4 * 0. 050 0.00250 0.00250 1.0070 0. 20 0.0050 0.00175 0.00075 • - 5 * 0. 050 0.00250 0.00250 1. 0050 0. 20 0.0000 0.00175 0.00075 一 6 * 0.050 0.00250 0.00250 1.0070 0. 20 0.0050 0.00000 0.00000 觸 • 7 * 0. 050 0.00250 0.00250 1.0050 0. 20 0.0050 0.00125 0.00125 — • 8 0. 050 0.00250 0.00250 1.0070 0.20 0.0050 0.00175 0.00075 一 9 0. 050 0.00275 0.00225 1.0100 0. 20 0.0025 0.00175 0.00075 10 0.050 0.00225 0.00275 1.0070 0. 20 0.0050 0.00175 0.00075 一 一 11 0. 050 0.00250 0.00250 1.0100 0. 20 0.0050 0.00188 0.00063 一 一 12 0. 050 0.00250 0.00250 1.0070 0.20 0.0050 0.00213 0.00038 一 1 3 * 0. 150 0.00250 0.00250 1.0100 0. 20 0.0050 0.00175 0.00075 一 1 4 * 0. 050 0.01000 0.01000 1.0150 0. 20 0.0050 0.00175 0.00075 一 1 5 * 0. 050 0.00400 0.00100 1.0050 0. 20 0.0050 0.00175 0.00075 — 1 6 * 0. 050 0.00250 0.00250 1.0070 0. 35 0.0050 0.00175 0.00075 — 1 7 * 0. 050 0.00250 0.00250 1.0070 0. 20 0.0500 0.00175 0.00075 1 8 * 0. 050 0.00250 0.00250 1.0050 0. 20 0.0050 0.00700 0.00300 1 9 # 0.050 0.00250 0.00250 1.0050 0. 20 0.0050 0.00225 0. 00025 2 0 * 0.050 0.00250 0.00250 0,9950 0. 20 0.0050 0.00175 0.00075 2 ’1 * 0. 050 0.00250 0.00250 1.0500 0. 20 0.0050 0.00175 0.00075 2 2 * 0. 050 0.00250 0.00250 1.0050 0. 20 0.0050 0.00175 0.00075 0.0001 2 3 0. 050 〇.00250 0.00250 1.0070 0. 20 0.0050 0.00175 0.00075 0.0100 麵 2 4 * 0. 050 〇.00250 0.00250 1.0050 0. 20 0.0050 0. 00175 0.00075 0. 1000 _ 2 5 * 0. 050 〇.00250 0.00250 1.0070 0. 20 0. 0050 0.00175 0. 00075 0.0010 2 6 0. 050 〇.00250 0.00250 1.0050 0. 20 0.0050 0.00175 0.00075 0. 1000 2 7s 0. 050 〇.00250 〇.00250 1.0070 0. 20 0.0050 0.00175 〇.00075 〇· 5〇or 2_8 0. 050 0.00250 0.00250 1.0050 0. 20 0.0050 0.00175 0.00075 0.0500 0.0500 *標計為不符合本發明所介定者。 G張尺度適用中國國家標準(CNS)A4 ‘格⑽X 297公爱) (請先閱讀背面之注意事項再填寫本頁) - 訂· •線' 553920 A7 -----~--—— B7 五、發明綱(51 ' -- 將結塊之介電組成粗胚研磨成粉狀後乾燥,接著以 1150 C的溫度鍛燒兩小時,即得到鍛燒細粉。再將鍛燒細 ’f刀經乾碾後可得到粒徑小於丨# m之鍛燒粉末。以濕式混 合(添加少量純水、聚乙烯乙醯黏結劑或乙醇溶劑到鍛燒 為末中,讓鍛燒粉末如陶土般可被凝塑)來將鍛燒粉末塑 k成陶瓷片體,以刮刀成型(d〇ct〇r bia(je )技術將陶瓷 片體製成6/zm之厚度,接著將主要含有鎳成份之内電極 印刷到陶瓷片體上。 ‘ 堆疊多層帶有内電極陶瓷片體後即可得到多層陶瓷電 容器之初體,其堆疊方式是以部份交錯重疊方式,讓每一 層陶瓷片體側邊略為突出,之後將初體先在氮氣() 環i兄下以350 C溫燒去除黏結劑,再提高溫度至1 24q它 (二小時),以還原氣氛(氫氣、氮氣與氧分壓2χ1(Γ10- 3xl(T12大氣壓之混合氣狀態)狀態燒結後得到多層陶莞電 容器。 成形後之多層陶瓷電容器以S Ε Μ觀察,並量測晶粒 大小’其ϊ測結果如下表二: (請先閱讀背面之注意事項再填寫本頁) - 訂· -線· 經濟部智慧財產局員工消費合作社印製 樣本號碼 介電常數 ε 晶粒大小 β m 密度 (g/cm3) 變化導因於溫度之 電谷比(△C/C〗。) 最大值 最小值 r 5 0 0 0 2 5 · 6 0 2 0 一 5 1 2* 7 0 0 0 1 · 8 5 · 6 0 18 ------- 一 4 2 3* 1 5 0 0 0 2 · 6 5*50 10 一 3 5 適 度 尺 !張 紙 I本 97 2 X 10 2 /V 格 規 ΙΑ4 S) Ν (C 準 標 家 553920 Α7Β7 五、發明說明(6) 經濟部智慧財產局員工消費合作社印製 4* 6 0 0 0 2 · 7 5 · 4 0 12 1 -6 0 5* 2 0 0 0 0 4 · 2 5 · 9 0 6 0 一 8 0 6* 8 0 0 0 • 1 5 · 6 0 15 一 4 0 T 1 8 5 0 0 3 · 1 5-82 5 -7 5 8 1 8 0 0 0 2 · 1 5 · 9 3 10 -7 0 9 1 7 0 0 0 2 · 3 5 · 9 2 11 一 7 4 10 1 6 5 0 0 2 5 · 9 0 15 -7 6 11 1 7 0 0 0 2 · 4 5-93 18 -7 2 12 1 8 5 0 0 2 · 2 5 · 9 1 17 -6 9 13* 7 0 0 0 3 * 1 5*60 4 6 一 4 6 14* 半導化 15* 1 7 0 0 0 2 · 8 5 · 8 5 5 -8 0 16* 3 0 0 0 2 5 · 4 0 5 5 -5 0 17* 1 7 0 0 0 4 · 9 5 · 8 1 10 -8 5 18* 半導化 19* 2 0 5 0 0 2 · 1 5 · 9 0 2 3 -8 3 20* 半導化 2Γ _ 0 · 5 5 · 4 0 燒結不良 22* 1 8 0 0 0 2 · 1 5 · 9 0 10 -70 23 1 8 5 0 0 1 * 7 5 · 9 1 8 -6 5 24* 9 0 0 0 3 · 5 5 · 8 8 12 一 8 0 25* 1 8 0 0 0 2 · 1 5 · 9 0 10 -70, 26 1 8 3 0 0 1.8 5 · 9 3 9 -6 8 8 (請先閱讀背面之注意事項再填寫本頁) 線· 本紙張尺度適用中國國家標準(CNS)A4規格(210 X 297公釐) 553920 A7 B7 五 、發明說明( 28 1 8 6 0 〇 半 導 化 9 2 5十為不符合本發明所介定者。 8 ^在夕層陶瓷電容器兩端沾浸銅膠以形成外電極,並在 氮氣(N2)環境下以9〇〇。(:處理銅膠,讓内外電極連通, 之後在室溫與IKHz和lVrms控制條件下下,以自動架橋 量測儀量測多層陶竞電容器之電容與溫度變化之電容改^ 比例’量測出之變化值同樣列於表二。其中當電容器於 20C時,電容改變比例之最大值與最小值介於―烈和肋 之間。 線 由表一與表二中對照觀察可知,其中未含有鈣成份00 之欽酸鋇基(Ba—zCaxYyYbzMTiitkdZraMnbNbcMo 成,如樣本1為不良組成,其顯現出介電常數低於 10’ 000之劣$燒結能力,另一方面,妈成份超過〇· π之 樣本13同樣為介電常數低於1M〇〇、劣質燒結能力之不 良組成,可符合Y5VEIA規格。 當釔鐘成份(y+z)為〇,如樣品2時同樣為不良組 成,其顯現出低介電常數與劣質燒結能力,另一方面,釔 镱成份超過0.02之樣本14則因為在還原氣氛的燒結過程 中半導化,而顯現出低絕緣阻力。 以紀鏡成份比(y/z)來看,低於〇 25之例子如樣本 3顯不出劣質的燒結能力,另一方面,釔鐘成份比超過 4.0之樣本15則有形成晶粒過大、超過2·5//ΙΠ的現象。 本紙張尺度適用中國國豕標準(CNS)A4規格(21〇 X 297公爱 553920 A7 B7 五、發明說明( 另外,在鍅成份(a)方面為ο、 如樣本4時,其顯現 出介電常數低於10,000之劣質捧,士 At丄 ’ 、 貞^疋結忐力,另一方面,錯 成份超過0· 35之樣本16同樣為介番a 永与,丨電常數低於10,000、劣 質燒結能力可符合Y5VEIA規袼之不良組成。 以猛成份⑴來看’其成份為G之例子如樣本5顧 示出形成超過2.5”之過大晶粒可符合Y5veu規格,另 -方面,鈒成份超過G.05之樣本17同樣有形成超過2·5 /z m之過大晶粒的問題,可符合yweia規格。 以鈮鉬總成份(c+d)來看,鈮鉬總成份為〇、如樣本6 時,其顯現出低於10,000之介電常數與劣質燒結能力, 另一方面,鈮鉬總成份超過0·01,如樣本18時,其因為 在還原氣氛的燒結過程中半導化,而顯現出低絕緣阻力。 另外在銳鉬成份比(c/d)方面,如樣本7,當銳成 份比小於1時,其顯示出形成超過2·5 Am之過大晶粒, 另一方面,當鈮鉬成份比大於9,如樣本19時,同樣為 不良組成,可符合Y5VEIA規袼。 § Ba/Ti比例(η)為0· 995時’如樣本20,其因為在 還原氣氛的燒結過程中半導化,而顯現出低絕緣阻力,另 7方面’ Ba/Ti比例大於1.05,如樣本21時,並無晶粒 長成,其燒結能力低劣。 另外在添加燒結劑部份,當〇· 〇〇〇1莫耳的氧化銅 (CuO)加入 1〇〇 莫耳的(Baity_zCaxYyYbz)n(Tiiabc dZraMribNbeMoOOw鈦酸鋇基組成中燒結,如樣本22所示/ 並無法發現添加氧化銅後有何不同,而如樣本23,當氧 1〇 本紙張尺度適用中國國家標準(CNS)A4規格(21〇 x 297公釐) (請先閱讀背面之注意事項再填寫本頁) · -丨線· 經濟部智慧財產局員工消費合作社印製 553920 A7 B7 五、發明說明( =添加量增加為G.G1莫耳時,較之於未添加氧化鋼, 樣本23❿成有小晶粒同時有較高之介電常數。另外,备 添加劑為0· 1莫耳時,如样太μ ^ ^ 田 关今于如樣本24,其介電常數則 10, 000,樣本24為不良之組成。 -、 項 當0.001莫耳的二氧化石夕(Si〇2)加入1〇〇莫耳的. &quot;-zCaxYyYbzMTnm-dZraMnbNbcMoOOw 鈦酸鋇基組成中婷 結’如樣纟25所示,並無法發現添加二氧切後有何ς 同,而如樣本26,當二氧化矽添加量增加為〇1莫耳 時,較之於未添加二氧化矽,樣本26形成有小晶粒同時 有較咼之介電常數。另外,當添加劑為〇. 5莫耳時,如樣 本27,其因為在還原氣氛的燒結過程中半導化,而顯現 出低絕緣阻力。 訂 由上述之實驗可知,可以歸納出一種製作多層陶瓷電 容器之的鈦酸鋇基介電組成,其組成如下: (Bai-x-y-zCaxYyYbz)n(Ti 1 ~a-b-c_d ZraMnbNbcM〇d)〇3+5 其中 線 〇&lt; χ &lt; 0· 15 〇&lt; y + z &lt; 〇. 〇2 0. 25&lt;y/z&lt;4. 00 〇&lt; a&lt; 〇. 35 〇&lt; b&lt; 〇. 〇5 〇&lt; c+d&lt; 〇· 〇l 1. 0&lt; c/d&lt; 9. 0 l.〇&lt;n&lt;l.〇5 6為結合氧原子之偏差值 11 本紙張尺度適用中國國家標準(CNS)A4規格(21G χ 297公爱) 553920 A7 五、發明說明(f〇 ) (請先閱讀背面之注意事項再填寫本頁) 該種欽酸鎖基介電組成使用無還原性介電材質,讓戶斤 製出之多層陶瓷電容器具有大於15000之高介電常數,並 讓電容對溫度的變化比例維持在-25到85之間,可符人 Y5VEIA規袼,此外,此種多層陶瓷電容器之介電組成並 可在低於1300°C溫度下燒結成功,同時具有小晶粒(直徑 小於 2. 5mm)。 因此,本發明具有下列之優點: 1.使用此種鈦酸鋇基介電組成之陶瓷電容器不會被 還原和半導化。 2 ·多層陶瓷電容器之成本可以降低,因為本組成可 在低於130(TC下的低溫燒結,使得内電極可以替換成低 成本之皁金屬。 •線· 3 ·本發明之陶瓷電容器介電組成具有高於15〇〇〇之 介電常數’而且儘管有高介電常數,其晶粒並可小於2 5 #爪,+所以在降低陶竟電容器之厚度下,晶粒數並不會減 少,藉此達到縮小陶瓷電容器體積的目的。 綜上所述,本發明之陶瓷電容器之介電質組成確實為 經濟部智慧財產局員工消費合作社印製 一極具產業上利用性之優良發曰月,因此具文申請發明專 利。、 Explanation of the invention (3 Porcelain Leiyi 'still has a dielectric composition of 鬲 dielectric constant to reduce the volume of multi-layer Tao Wendian Gu Yi. 2. The purpose of the invention described above, the technical means used in the present invention is to use the following Sintered dielectric composition: (Bah, zCaxYyYbz) n (Ti ^ —dZrJiibNbcMocOOw Its towel 〇 &lt; X &lt; 0.15 〇 &lt; y + ζ &lt; 〇. 〇2 0.25 &lt; y / z &lt; 4.00 〇 &lt; a &lt; 0.35 〇 &lt; b &lt; 0. 05 〇 &lt; c + d &lt; 0 · 01 1 · 〇 &lt; c / d &lt; 9. · 1.0 1.0 &lt; n &lt; 1.05 5 is the deviation value of the bound oxygen atom The dielectric composition of the ceramic valley device is characterized in that the dielectric composition contains a trace amount of epoch metal in the barium molecular group, and the niobium molybdenum metal in the titanium atom group is micro, and the copper silicon oxide is additionally added during the sintering process. As a sintering agent. In order for your review committee to further understand the principle and efficacy of the present invention, the following operating examples and analysis experiments are provided: First prepare sintering raw materials BaC〇3, CaC〇3, ~ Y2〇3, Yb2 03, Ti02, Zr02, MnO, Nb205, Mo03, CuO, Si〇2, this paper size is applicable to China Home Standard (CNS) A4 Specification ⑽ x 297 Public Miscellaneous ... (Please read the notes on the back before filling out this page), .------- ^ — „—— Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs X Consumer Cooperative 553920A7_-_B7__., ^^ V. Description of the invention (^) and the selective addition of copper and silicon oxides, such as CuO, Si〇2 as sintering agent, the sintering raw materials are mixed and agglomerated to form (Bam-zCaxYJbzMTibua -b_c_ dZraMnbNbcM〇d) 〇3 + 5 The rough composition of the dielectric composition, where the values of x, y, z, n, a, b, c must conform to the following table 1: · Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs Sample main ingredient composition additive (Bs 1 -χ-yz C &lt; axYyYbz) n (T i 1-abcd ZraMnbNbcM〇d) 〇3 + δ XYZ η ABC d CuO Si〇2 1 * 0.00 0.00250 0.00250 1.0070 0. 20 0.0050 0.00175 0.00075 _-2 * 0. 050 0.00000 0.00000 1.0050 0. 20 0.0050 0.00175 0.00075 one-3 * 0. 050 0.00100 0.00400 1.0070 0. 20 0.0050 0.00175 0.00075 one 4 * 0. 050 0.00250 0.00250 1.0070 0. 20 0.0050 0.00175 0.00075 •-5 * 0. 050 0.00250 0.00250 1. 0050 0 .20 0.0000 0.00175 0.00075-6 * 0.050 0.00250 0.00250 1.0070 0. 20 0.0050 0.00000 0.00000 touch 7 * 0. 050 0.00250 0.00250 0.00250 1.0050 0. 20 0.0050 0.00125 0.00125 — • 8 0. 050 0.00250 0.00250 1.0070 0.20 0.0050 0.00175 0.00075 0.00075 1 0 .050 0.00275 0.00225 1.0100 0. 20 0.0025 0.00175 0.00075 10 0.050 0.00225 0.00275 1.0070 0. 20 0.0050 0.00175 0.00075 one-to-one 11 0. 050 0.00250 0.00250 1.0100 0. 20 0.0050 0.00188 0.00063 one-to-one 12 0. 050 0.00250 0.00250 1.0070 0.20 0.0050 0.00213 0.00038 Mon 1 3 * 0. 150 0.00250 0.00250 1.0100 0. 20 0.0050 0.00175 0.00075 Mon 1 4 * 0. 050 0.01000 0.01000 1.0150 0. 20 0.0050 0.00175 0.00075 Mon 1 5 * 0. 050 0.00400 0.00100 1.0050 0. 20 0.0050 0.00175 0.00075 — 1 6 * 0. 050 0.00250 0.00250 1.0070 0. 35 0.0050 0.00175 0.00075 — 1 7 * 0. 050 0.00250 0.00250 1.0070 0. 20 0.0500 0.00175 0.00075 1 8 * 0. 050 0.00250 0.00250 1.0050 0. 20 0.0050 0.00700 0.00300 1 9 # 0.050 0.00250 0.00250 1.0050 0. 20 0.0050 0.00225 0. 00025 2 0 * 0.050 0.00250 0.00250 0,9950 0. 20 0.0050 0.00175 0.00075 2 '1 * 0. 050 0.00250 0.00250 1.0500 0. 20 0.0050 0.00175 0.00075 2 2 * 0. 050 0.00250 0.00250 1.0050 0. 20 0.0050 0.00175 0.00075 0.0001 2 3 0 . 050 〇.00250 0.00250 1.0070 0. 20 0.0050 0.00175 0.00075 0.0100 Face 2 4 * 0. 050 〇.00250 0.00250 1.0050 0. 20 0.0050 0. 00175 0.00075 0. 1000 _ 2 5 * 0. 050 〇.00250 0.00250 1.0070 0 .20 0. 0050 0.00175 0. 00075 0.0010 2 6 0. 050 〇.00250 0.00250 1.0050 0. 20 0.0050 0.00175 0.00075 0. 1000 2 7s 0. 050 〇.00250 〇.00250 1.0070 0. 20 0.0050 0.00175 〇.00075 〇 · 5〇or 2_8 0. 050 0.00250 0.00250 1.0050 0. 20 0.0050 0.00175 0.00075 0.0500 0.0500 * The mark is not in accordance with the definition of the present invention. G-scale scales are applicable to China National Standard (CNS) A4 'Ge X X 297 public love) (Please read the precautions on the back before filling this page)-Order · • Line' 553920 A7 ----- ~ ------ B7 V. Outline of the Invention (51 '-Grind the agglomerated dielectric composition coarse embryos into powders and dry them, and then calcine at 1150 C for two hours to obtain calcined fine powder. After the knife is dry-rolled, a calcined powder with a particle size smaller than 丨 # m can be obtained. Wet-mix (add a small amount of pure water, polyethylene acetic acid binder or ethanol solvent to the calcined powder, and let the calcined powder such as clay It can be coagulated) to shape the calcined powder into a ceramic sheet body, and the ceramic sheet body is made into a thickness of 6 / zm by a doctor blade technique (doctor bia (je) technology), and then mainly contains nickel. The internal electrode is printed on the ceramic sheet body. '' After stacking multiple layers of ceramic sheet bodies with internal electrodes, the initial body of the multilayer ceramic capacitor can be obtained. The stacking method is partly staggered, so that each side of the ceramic sheet body Slightly prominent, and then the precursor is first burned under a nitrogen () ring at 350 C to remove the binder, and then the temperature is increased. Until 1 24q it (two hours), the multilayer ceramic capacitor is obtained by sintering in a reducing atmosphere (hydrogen, nitrogen and oxygen partial pressure 2χ1 (Γ10-3xl (mixed gas state of T12 atmosphere)). The multilayer ceramic capacitor after forming is S Ε Μ Observe and measure the grain size. The results are shown in Table II: (Please read the precautions on the back before filling out this page)-Order ·-Line · Ministry of Economic Affairs Intellectual Property Bureau Employees Consumer Cooperatives printed sample numbers Dielectric constant ε Grain size β m Density (g / cm3) The change is due to the temperature-to-valley ratio (△ C / C). Maximum and minimum r 5 0 0 0 2 5 · 6 0 2 0-5 1 2 * 7 0 0 0 1 · 8 5 · 6 0 18 ------- 1 4 2 3 * 1 5 0 0 2 · 6 5 * 50 10 1 3 5 Moderate rule! Sheet of paper I 97 2 X 10 2 / V Standard ΙΑ4 S) Ν (C Standard bidder 553920 Α7Β7 V. Description of the invention (6) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 4 * 6 0 0 0 2 · 7 5 · 4 0 12 1 -6 0 5 * 2 0 0 0 0 4 · 2 5 · 9 0 6 0-8 0 6 * 8 0 0 0 • 1 5 · 6 0 15-4 0 T 1 8 5 0 0 3 · 1 5- 82 5 -7 5 8 1 8 0 0 0 2 · 1 5 · 9 3 10 -7 0 9 1 7 0 0 0 2 · 3 5 · 9 2 11-7 4 10 1 6 5 0 0 2 5 · 9 0 15 -7 6 11 1 7 0 0 0 2 · 4 5-93 18 -7 2 12 1 8 5 0 0 2 · 2 5 · 9 1 17 -6 9 13 * 7 0 0 0 3 * 1 5 * 60 4 6-4 6 14 * Semiconducting 15 * 1 7 0 0 0 2 · 8 5 · 8 5 5 -8 0 16 * 3 0 0 0 2 5 · 4 0 5 5 -5 0 17 * 1 7 0 0 0 4 · 9 5 · 8 1 10 -8 5 18 * semiconductive 19 * 2 0 5 0 0 2 · 1 5 · 9 0 2 3 -8 3 20 * Semiconductive 2Γ _ 0 · 5 5 · 4 0 Poor sintering 22 * 1 8 0 0 0 2 · 1 5 · 9 0 10 -70 23 1 8 5 0 0 1 * 7 5 · 9 1 8 -6 5 24 * 9 0 0 0 3 · 5 5 · 8 8 12-8 0 25 * 1 8 0 0 0 2 · 1 5 · 9 0 10 -70, 26 1 8 3 0 0 1.8 5 · 9 3 9 -6 8 8 (Please read the precautions on the back before filling in this page) Line · This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) 553920 A7 B7 V. Description of the invention (28 1 8 6 0 0 Semiconducting 9 2 50 10 is not in accordance with the present invention. 8 ^ Dipping copper paste on both ends of the ceramic capacitor to form an external electrode, and under a nitrogen (N2) environment at 900. (: Process the copper glue to connect the internal and external electrodes, and then measure the capacitance and temperature change of the multilayer ceramic capacitor with an automatic bridge measuring instrument under room temperature and IKHz and lVrms control conditions. The change values are also listed in Table 2. When the capacitor is at 20C, the maximum and minimum values of the capacitance change ratio are between Li and Ri. The line can be seen from the comparison between Table 1 and Table 2. It does not contain calcium Composition 00 is made of barium octylate (Ba-zCaxYyYbzMTiitkdZraMnbNbcMo). If sample 1 is a bad composition, it exhibits a dielectric constant lower than 10'000. $ Sintering ability. On the other hand, sample 13 whose maternal component exceeds 0 · π It is also a bad composition with a dielectric constant below 1M00 and inferior sintering ability, which can meet the Y5VEIA specification. When the yttrium bell component (y + z) is 0, it is also a bad composition as in sample 2, which shows a low dielectric constant. Constant and inferior sintering ability. On the other hand, the sample 14 with yttrium-rhenium composition exceeding 0.02 exhibits low insulation resistance due to semiconductivity during sintering in a reducing atmosphere. Judging from the composition ratio (y / z) ,low In the example of 〇25, if sample 3 does not show inferior sintering ability, on the other hand, sample 15 with an yttrium bell component ratio of more than 4.0 has a phenomenon of excessively large crystal grains and exceeds 2.5 · // ΙΠ. This paper size applies China National Cricket Standard (CNS) A4 specification (21〇X 297 public love 553920 A7 B7 V. Description of the invention (In addition, in the case of tritium component (a), it is ο. When sample 4, it shows a dielectric constant lower than 10,000 Inferior quality is good, and At 丄 'and Zhen ^ are strong. On the other hand, the sample 16 with the wrong component more than 0.35 is also the same. The electric constant is less than 10,000 and the inferior sintering ability can meet Y5VEIA. The bad composition of the rule. Seen from the fierce composition, for example, its composition is G. As shown in sample 5, Gu shows that the formation of excessively large grains exceeding 2.5 "can meet the Y5veu specification. In addition, on the other hand, the sample whose radon composition exceeds G.05. 17 also has the problem of forming excessively large grains exceeding 2.5 · zm, which can meet the yweia specification. In terms of the total niobium molybdenum composition (c + d), the total niobium molybdenum composition is 0. As shown in Sample 6, it appears Dielectric constant below 10,000 and poor sintering ability, on the other hand, niobium molybdenum assembly When it exceeds 0.01, such as sample 18, it shows low insulation resistance because of semiconductivity during sintering in a reducing atmosphere. In addition, in terms of sharp molybdenum composition ratio (c / d), such as sample 7, when the sharp component When the ratio is less than 1, it shows the formation of excessively large grains exceeding 2.5 Am. On the other hand, when the ratio of the niobium molybdenum component is greater than 9, such as sample 19, it is also a bad composition, which can meet the Y5VEIA regulations. § Ba / When the Ti ratio (η) is 0.995 ', as in Sample 20, it exhibits low insulation resistance because of semiconductivity during sintering in a reducing atmosphere. In the other 7 aspects, the Ba / Ti ratio is greater than 1.05, as in Sample 21. There is no grain growth, and its sintering ability is poor. In addition, in the sintering agent addition section, when 0.001 mol copper oxide (CuO) was added to 100 mol (Baity_zCaxYyYbz) n (Tiiabc dZraMribNbeMoOOw barium titanate-based composition, as shown in Sample 22) / Can not find any difference after adding copper oxide. For example 23, when the paper size of oxygen is 10, the Chinese national standard (CNS) A4 specification (21〇x 297 mm) is applied (please read the precautions on the back first) (Fill in this page) ·-丨 Line · Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 553920 A7 B7 V. Description of the invention (= When the added amount is increased to G.G1 Mohr, compared with the non-oxidized steel, sample 23% There are small crystal grains and high dielectric constant. In addition, when the additive is 0.1 mol, the sample is too μ ^ ^ Tian Guanjin Yuru sample 24, the dielectric constant is 10,000, sample 24 It is a bad composition.-, When 0.001 mol of dioxide (Si〇2) is added to 100 mol. &Quot; -zCaxYyYbzMTnm-dZraMnbNbcMoOOw Ting Junction in the barium titanate-based composition as shown in Figure 25 Display, and could not find any difference after adding dioxin, as in sample 26, when When the amount of silicon oxide was increased to 0 mol, compared with no silicon dioxide added, sample 26 formed small grains and had a relatively high dielectric constant. In addition, when the additive was 0.5 mol, such as Sample 27, which exhibits low insulation resistance because it is semiconductive during sintering in a reducing atmosphere. According to the experiments described above, a barium titanate-based dielectric composition for the manufacture of multilayer ceramic capacitors can be summarized. It is as follows: (Bai-xy-zCaxYyYbz) n (Ti 1 ~ ab-c_d ZraMnbNbcM〇d) 〇3 + 5 where the line 〇 &lt; χ &lt; 0.15 〇 &lt; y + z &lt; 〇2 〇2 0. 25 &lt; y / z &lt; 4.0 00 &lt; a &lt; 0.35 〇 &lt; b &lt; 〇. 〇5 〇 &lt; c + d &lt; 〇1. 0 &lt; c / d &lt; 9. 0 l. 〇 &lt; n &lt; l.〇5 6 is the deviation value of the combined oxygen atom 11 This paper size applies the Chinese National Standard (CNS) A4 specification (21G x 297 public love) 553920 A7 V. Description of the invention (f) (Please read the notes on the back and fill in this page) This kind of caprylic acid-based dielectric composition uses a non-reducing dielectric material, allowing the multilayer ceramic capacitors made by households to have a height of more than 15000 The electric constant, and keep the change ratio of capacitance to temperature between -25 and 85, can meet the Y5VEIA regulations. In addition, the dielectric composition of this multilayer ceramic capacitor can be sintered successfully at a temperature below 1300 ° C 5mm), while having small grains (diameter less than 2. 5mm). Therefore, the present invention has the following advantages: 1. A ceramic capacitor using such a barium titanate-based dielectric composition is not reduced and semiconductive. 2 · The cost of multilayer ceramic capacitors can be reduced because the composition can be sintered at a low temperature of less than 130 ° C, so that the internal electrode can be replaced with a low-cost soap metal. • Wire · 3 · Dielectric composition of the ceramic capacitor of the present invention It has a dielectric constant higher than 150,000, and despite its high dielectric constant, its crystal grains can be smaller than 2 5 #claws, so the number of crystal grains will not decrease when the thickness of the ceramic capacitor is reduced. In order to achieve the purpose of reducing the volume of ceramic capacitors. In summary, the dielectric composition of the ceramic capacitors of the present invention is indeed printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs with a very good industrial availability, Therefore, an application for a patent for invention was filed.

II ‘紙張尺度適家標準(cns)a^^ (210 x 297 公釐)II ‘Paper Standards (cns) a ^^ (210 x 297 mm)

Claims (1)

553920 A8 B8 C8553920 A8 B8 C8 經濟部智慧財產局員工消費合作社印製 1 · 一種多層陶瓷電容器之介電組成,其組成成份如 下: (Ba 1-χ-y-z CaxYyYbz)n(Ti i-a-b-c-dZraMnbNbcM〇d)〇3+(5 其中 〇&lt; x &lt; 0. 15 〇&lt; y + z &lt; 0. 02 0. 25 &lt; y/z&lt; 4. 00 〇&lt;a&lt;0.35 〇&lt;b&lt; 0· 05 〇&lt; c+d&lt; 0. 01 1.0&lt;c/d&lt;9.0 1.0&lt;n&lt; 1.05 5為結合氧原子之偏差值 該陶瓷電容器之介電組成其特徵在於··此介電: 組成在鋇分子團中含有微量之釔鏡金屬,鈦原子團中一 具有微量之鈮鉬金屬,此組成範圍内之介電組成具 有高於15000之介電常數與小於2· 11]的晶粒;與 在燒結過程中添加銅石夕氧化物作為燒結劑。 2·如申請專利範圍第1項之多層陶瓷電容器之介電 組',其中銅石夕氧化物之燒結劑為氧化銅,其添加比例為 100莫耳專利範圍第丄項中之介電組成對〇〇〇卜〇 之氧化銅。 ·、斗 3 ’如申請專利範圍第1項之多層陶瓷電容器之介竜 組成,其中銅矽氧化物之燒結劑為二氧化矽,其添加比伤 (請先閱讀背面之注意事項再填寫本頁) -I--------.--- 線丨 0 1¾ 553920 Α8 Β8 C8 D8 、申請專.利範圍 為100莫耳的專利範圍第1項中之介電組成對0·001_0· 5 莫耳之二氧化矽。 (請先閱讀背面之注意事項再填寫本頁) -線· 經濟部智慧財產局員工消費合作社印製 Η 本紙張尺度適用中國國家標準(CNS)A4規格(210 X 297公爱)Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs1. The dielectric composition of a multilayer ceramic capacitor, the composition of which is as follows: (Ba 1-χ-yz CaxYyYbz) n (Ti iabc-dZraMnbNbcM〇d) 〇3 + (5 where 〇 &lt; x &lt; 0. 15 〇 &lt; y + z &lt; 0.02 0. 25 &lt; y / z &lt; 4. 00 〇 &lt; a &lt; 0.35 〇 &lt; b &lt; 0.05 〇 &lt; c + d &lt; 0. 01 1.0 &lt; c / d &lt; 9.0 1.0 &lt; n &lt; 1.05 5 is the deviation value of the bonded oxygen atom The dielectric composition of the ceramic capacitor is characterized by this dielectric: The composition is in the barium molecular group Contains a trace amount of yttrium mirror metal, a trace amount of niobium molybdenum metal in the titanium atomic group, the dielectric composition in this composition range has a dielectric constant higher than 15000 and grains smaller than 2.11]; and added in the sintering process As a sintering agent, the cuprite oxidant is used as the sintering agent. 2. The dielectric group of the multi-layer ceramic capacitors according to item 1 of the patent application, wherein the sintering agent of the cuprite oxidant is copper oxide, and the addition ratio is 100 mol The dielectric composition in item (2) is copper oxide of 〇00〇〇。, "3" as in the patent application scope of the multilayer ceramic The dielectric composition of the capacitor, the sintering agent of copper silicon oxide is silicon dioxide, and its specific damage (please read the precautions on the back before filling this page) -I --------.--- Line 丨 0 1¾ 553920 Α8 Β8 C8 D8, apply for patent. The dielectric composition in item 1 of the patent scope is 100 mol. The dielectric composition is 0 · 001_0 · 5 mol of silicon dioxide. (Please read the note on the back first Please fill in this page for further information)-Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs Η This paper size is in accordance with China National Standard (CNS) A4 (210 X 297 public love)
TW91101639A 2002-01-31 2002-01-31 Dielectric composition for multi-layers ceramics capacitor TW553920B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
TW91101639A TW553920B (en) 2002-01-31 2002-01-31 Dielectric composition for multi-layers ceramics capacitor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
TW91101639A TW553920B (en) 2002-01-31 2002-01-31 Dielectric composition for multi-layers ceramics capacitor

Publications (1)

Publication Number Publication Date
TW553920B true TW553920B (en) 2003-09-21

Family

ID=31974803

Family Applications (1)

Application Number Title Priority Date Filing Date
TW91101639A TW553920B (en) 2002-01-31 2002-01-31 Dielectric composition for multi-layers ceramics capacitor

Country Status (1)

Country Link
TW (1) TW553920B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116635348A (en) * 2020-09-10 2023-08-22 基美电子公司 Dielectric ceramic composition and ceramic capacitor using the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116635348A (en) * 2020-09-10 2023-08-22 基美电子公司 Dielectric ceramic composition and ceramic capacitor using the same

Similar Documents

Publication Publication Date Title
JP5829232B2 (en) Dielectric ceramic composition and multilayer ceramic capacitor including the same
JP4821357B2 (en) Electronic component, dielectric ceramic composition and method for producing the same
JP5217742B2 (en) Dielectric porcelain composition and electronic component
TWI321126B (en) Electronic device, dielectric ceramic composition and the production method
JP5801274B2 (en) Dielectric composition and ceramic electronic component including the same
JP6651351B2 (en) Dielectric ceramic composition and ceramic electronic component containing the same
JP2011136896A (en) Dielectric ceramic composition and multilayer ceramic capacitor containing the same
JP2009120466A (en) Dielectric composition sinterable at low temperature for reinforcing hot insulation resistance and multilayer ceramic capacitor using the same
JP2017114759A (en) Dielectric ceramic composition, dielectric material and multilayer ceramic capacitor including the same
JP2008254988A (en) Dielectric ceramics and method for producing the same, and monolithic ceramic capacitor
JP2013136501A (en) Dielectric composition and ceramic electronic part including the same
JP4396608B2 (en) Dielectric porcelain composition and electronic component
JP2007254211A (en) Electronic component, dielectric ceramic composition and production method of the dielectric ceramic composition
JP3435607B2 (en) Non-reducing dielectric porcelain composition
JP2011162396A (en) Dielectric ceramic composition and electronic component
JP5194370B2 (en) Electronic component, dielectric ceramic composition and method for producing the same
JP4561922B2 (en) DIELECTRIC CERAMIC COMPOSITION, ELECTRONIC COMPONENT AND METHOD FOR PRODUCING THEM
JP5067535B2 (en) Dielectric porcelain composition and electronic component
JP2008135638A (en) Multilayer ceramic capacitor
TW553920B (en) Dielectric composition for multi-layers ceramics capacitor
JP2014198660A (en) Dielectric ceramic composition and multi-layer ceramic capacitor comprising the same
JP2007258476A (en) Laminated electronic component and manufacturing method thereof
JP2020043299A (en) Dielectric composition and electronic component
JP2007258477A (en) Laminated electronic component and manufacturing method thereof
JP2004203669A (en) Dielectric porcelain composition, electronic components, and manufacturing processes thereof

Legal Events

Date Code Title Description
GD4A Issue of patent certificate for granted invention patent
MK4A Expiration of patent term of an invention patent