506243 五、發明説明（1 ) 發明領域 本發明係關於一般之印刷電路，且特別是關於製造多 層印刷電路板之方法及用於一起堆疊及初步地接合該 組成其之子板（或附屬板）之機器。 發明背景 印刷電路之整合一直有增加程度，已導引至在多層板 上形成之印刷電路之實現。此多層板係由堆疊幾張預 作圖案之薄片子板（sub-board)，每一子板含有電路之一 部分，待最後熱壓在一起以形成，”單石”多層板。此多層 板之製造是由交替堆疊預作圖案之子板及玻璃纖維強 化塑膠之前身片（預漬片），並藉熱壓如此構成之多層堆 疊。在此堆疊熱壓之期間，預漬片上浸漬之樹脂溶化及 /或聚合化並將諸子板接合一起，以外又隔離相對之各 子板之圖案化金屬層之表面。 因爲是高度積體化之故，所以子板之堆疊必須極端的 準確。事實上，超過幾// m(微米）之對準誤差將使各子 板間之互連導通孔對不準。所以諸子板必須以極端精 密的方式堆疊及必須在熱壓期間保持完美之對準。 通常子板及預漬片皆被提供有諸孔在被界定之諸位 置上以正確地堆疊它們。如此之對準孔至少有兩個，但 可能有很多個，且這些對準孔是使用於堆疊子板及預漬 片於樣板之平行銷釘上。典型的樣板，如第1圖之實例 所描述是由其上有對準栓釘或銷釘2豎立之銅板1構 成，時常保持精密之可移位及可阻擋之滑動以配合堆疊 506243 五、發明説明（2 ) 平台之需要。 根據製造多層印刷電路板之已知方法，子板及預漬片 是堆疊在栓釘上，以上所述，最後頂端加上終端鋼板，與 子板及預漬片相似，此終端板具有對準孔以使自堆疊上 突出之對準栓釘之末端部通過。此堆疊，包括板與頂端 板即轉移至一壓機加以熱壓。在熱壓後，此多層板即滑 出堆疊夾具之對準栓釘。 此方法在熱壓期間能預防堆疊層之任何偶然之對準 誤差，但要要在壓機之緊壓平台間出現之樣板及終端板 二者有相當厚度（不小於1 〇酬厚）。因此限制在壓機之 平台間之可用空間，及在同一時間可熱壓之重整堆疊之 總數。更加，自對準栓釘上分離鋼板與多層板會因熔化 樹脂之傾向於侵入對準孔並在凝固時，藉栓釘而使多層 堆疊與鋼板”緊結”起來而有困難。 最近，代替技術已發展用於克服壓機上攜帶之兩個鋼 板之累贅之缺點及需要在每一次加壓後消除栓釘上樹 脂殘留物之缺點。這些技術是基於使用金屬或熱塑塑 料樹脂或使用加熱之衝頭以點熔接待加壓之多層堆 疊。此硏討是在緊結堆疊之諸層在一起，使允許處理及 轉移至壓機中而不會有任何堆疊層之對準誤差之危 險。 使用_釘造成不需要使用樣板，由於此鉚釘作動如對 準栓釘。在兩個或多個週邊點，，點熔接，，堆疊層之技術 仍需使用堆疊樣板。加熱之衝頭局部熔化預漬片上之 -4- 506243 五、發明説明（3 ) 樹脂，如此黏著其至子板並保持堆疊層在一起。一旦如 此之預緊結被實施，則堆疊則可滑下堆疊樣板之對準栓 釘並放置在壓機之平台間。 這些將諸子板預束縛在一起之技術之缺點是局部增 加堆疊之厚度。在第一案例中是固有鉚釘頭之故，而在 後一案例中是因在”點熔接”時樹脂之熱回流及凝聚之 故。 後者的方法更會限制產量，其因樹脂之局部化加熱及 聚合使堆疊可安全地處理及放置在壓機前需要超過一 分鐘。亦有對堆疊厚度之限制使其可如此使用加熱衝 頭之點”熔接”。 發明目的及簡沭 一種製造多層印刷電路板之方法及用於堆疊和預緊 結子板之機器已經發現，其允許實現多層印刷電路板之 方式較己知方法更有效率，並不會不當地限制可堆疊層 之數目。 根據本發明，一多層印刷電路板之製造方法是由在一 樣板上交替堆疊預作圖案之子板及絕緣之預漬板，並將 各層緊結在一起使構成一個堆疊，其是最後放置在壓機 的平台之間並熱加壓，致使浸入預漬片之樹脂回流及/ 或聚合化。 本發明之方法克服已知方法之缺點，因爲每個子板實 際是通過插入預漬片之孔而焊接至在下面平放之子 層。 發明説明（4 ) 具有一通孔之焊接墊是故意地形成在有關對準孔之 精密形成位置，至少在每個子板之下面表面上或兩面上， 但除在堆疊底下之第一子板之外。其上之焊接墊，即使 沒有任何通孔，是至少形成在上面表面。插置在堆疊子 板間之預漬片是有缺口或穿孔，以使其不會重疊在鄰接 子板之焊接墊上。 最佳是每個子板至少具有兩對有孔穿透之焊墊及相 同數目之無孔穿透之”盲”焊墊。最佳是某個子板之焊 墊之交互配置是如此使每個盲焊墊面對一堆疊在該子 板上之子板之有孔穿透之焊墊。 根據本實施例，有孔穿透之焊墊僅可形成在面對堆疊 下面平放之子板之每個子板之表面上。 根據本發明之另一觀點，子板及預漬片是由使用獨特 有效之機器合宜地堆疊及接合起來。 基本上，本機器之構成是由一具有多個對準栓釘之樣 板，及至少一對電焊接單元，由致動器自動地移動至剛 好堆疊在另一子板上之每個子板之有孔穿透之焊墊上 方’用以實施焊接並立刻縮回及離開裝配之堆疊至其 備用位置。 此自動焊接單元亦可提供有裝置用於在焊接期間加 壓待焊接之子板至下面平放之一個子板。 本發明之方法之要旨在於當多層堆疊之裝配期間，每 個小板一旦是放置在堆疊頂部上時則被焊接至下面平 放層。此允許將子板緊結在一起而沒有任何板數之限 506243 五、發明説明（5 ) 制。已知實際之焊接可在少於4秒鐘內執行，其可方便 的實施，同時操作員之手可自堆疊移開以拾取另一子板 以堆疊在其上。本發明是更精密的定義在附隨之申請 專利範圍中。 本發明之不同觀點及利益將由參考伴隨圖式及參閱 全部本發明實施例之詳細發明而成更爲明顯。 圖式簡II說明 第1圖是描述具有栓釘之樣板。 第2圖是界定在一子板上之兩種不同類之焊墊之詳 細視圖。 第3圖是解說如何堆疊子板及預漬片。 第4圖是描述二不同類焊墊之最佳配置。 第5圖是描述本發明機器之自動焊接單元及焊接之 放大視圖。 第6及第7圖是描述在第4圖之多層堆疊中造成之 焊接。 最佳實施例詳細說明 要實行本發明，適合準備之印刷電路子板及適合缺口 或穿孔之絕緣預漬片必須是現用的，如下文說明。 根據本發明，此用於堆疊及預緊結子板一起之機器包 含：一基礎樣板1，如第1圖所描述者，最佳是包覆一層 絕緣材料之鋼材並具有直立之對準對或栓釘2。 爲了要適應基礎樣板1至不同大小及形狀之堆疊子 板，故對準栓釘2皆是不固定的，如第1圖中描述之實 506243 五、發明説明（6 ) 例，但是它們可以更方便的安裝至可調節及可固定在所 想要之位置中之滑件上，運行在堆疊樣板之底板中界定 之導件中。最佳是第1圖中描述之對準栓釘2將以一 非鏡像方式配置在底板上以預防子板安裝顛倒或對樣 板上之正確堆疊取向迴轉。 最佳是如第2圖所描述之子板3。在其描述爲灰色 調之中央部分是形成爲印刷電路之圖案。對準孔5及 焊接墊6和7皆是形成在周邊部分4,該處不具印刷電 路之面貌。 周邊部分4僅用於此板之製造，並將於多層板經熱壓 後被修剪除去。 焊墊6及7分別在其之”盲”墊及穿孔墊之功能特徵 而不同。 然而，根據最佳實施例，即使焊墊6之功能是形成爲” 盲”墊，但可以方便的提供有一穿透小孔1 0以促進及造 成更有效之焊接。提供有一足夠大之穿透孔1 1之焊墊 7允許經其而執行焊接。焊墊7之孔Π容許熔化之焊 料合金滴過此孔而至下面平放子板之肓墊上，因此一旦 固化後，可把此兩個子板焊接在一起。 盲墊6(在其上有焊接發生的）可以不具有任何孔10 但呈現有相當小之孔亦是最好的。雖然此小孔有效地 阻止熔化焊料合金滴下但是可使此合金黏著至此盲墊 之小孔1 〇之內牆，因此會產生一加強之錨定。焊墊7 可由銅環8在玻璃纖維強化樹脂板9所成之圖案並具 506243 五、發明説明（7 ) 有約4至6 mm之外直徑，及形成中央孔1 〇之內直徑約 是2至3 mm。 相同外直徑之盲焊墊6可以提供一小的中孔Π，例 如在〇. 8至1腿之間之直徑。 自第2圖，可觀察兩個不同種類之焊墊6及7亦可實 現在首先放置在基礎樣板上之最低子板上。然而，考慮 焊接是作成在具有穿透小孔1 1之焊墊上，最低子板亦 可被提供僅有”肓”焊墊6。 堆疊子板3及預漬片12之方式是解說在第3圖中， 觀看其圖式可明顯的觀察到： 1) 預漬片12皆做成有缺口，不使重疊在子板3之周 邊部分4中形成之焊接墊6及7上。 2) 在穿透孔1 1之每個焊墊7壓在，並是垂直對準至 下面平放之子板3之盲焊墊6上。 預漬片1 2不重疊，即使是局部，在焊墊6及7之事實 是根本使熔化之焊料合金落下通過焊墊7之孔而達下 面平放之盲焊墊6預漬片1 2可具有缺口 1 3，對應於 第3圖之實例所描述之焊接墊切成，或可提供適宜大小 之孔。 在堆疊中各式預圖案化之子板3間插置之樹脂預漬 片1 2，其前身是介質玻璃纖維強化塑膠之中間層，最佳 生產方法是在於模壓衝出之長方形預漬片，同時衝出對 準孔14及缺口 13(或孔），以對應孔板3之焊墊6及7。 若焊墊有4至6 nun之外直徑，則在預漬片上這些孔可有 506243 五、發明説明（8 ) 1 〇至1 3醒之直徑。 在二種焊墊間互相交替對準之條件如上述第2點）項 而論，其是特別地方便但不是必需之條件以實行本發明 之方法。事實上僅選用有孔穿透之焊墊7，作全部互相 垂直對準並形成在子板3上即可，但堆疊之最低子板除 外。在本事例中，熔化合金一旦凝固後會構成伸延直通 經整個堆疊之焊料合金之不斷”鉚釘”一旦全部層板己 堆疊在樣板上就獲得一多層堆疊，如第4圖所描述。在 其放大剖面視圖中，可觀察到具有孔穿透之焊墊7是垂 直對準於間隔之盲焊墊6,其亦提供有一相當小之中孔 10。 本發明之機器之自動焊接單元1 6是槪要描述於第5 圖中。 一通常的電焊接元件1 6是由一致動旋臂之公用系統 1 8沿三度正交軸移動，並使用錫和銀或銅之焊料合金之 金屬線細絲1 7通過焊墊7之孔1 1而實施焊接。此機 器可方便提供至少一對焊接單元，因每個子板3是要至 少焊接在兩點上。 、 憑藉操作員之命令，旋臂1 8移動電焊接元件1 6至一 焊墊7之通孔1 1之上方口上。當焊接實施後，則焊接 元件被旋臂1 8移回至其之備用位置，在堆疊之外，以使 不干擾另一預漬片12之堆叠及另一子板3之堆疊。 若每個子板要焊接在兩點以上（例如在四個點），則此 機器應裝被設有第二對自動焊接單元，其係與第一對單 -10- 506243 五、發明説明（9 ) 元同時作動。 焊接單元熔接機器之引動旋臂1 8可由氣力缸移動。 焊接單元1 6可以是使用連續金屬線之通用的電烙鐵， 此金屬線是具有熔化點在攝氏2 5 0度至3 0 1度間之焊 料合金線。焊接早兀最佳是提供有設置以程式規劃其 之溫度及焊接時間（一般範圍在攝氏1 5 0至5 0 0度，達5 秒鐘之久），以及自動化饋送焊料。 可選擇地，如第5圖中所描述者，每個單元可包括一 靴掌1 5，其係用以壓下待焊接之子板經焊接單元之整個 介入期間。當此單元放下至有孔焊墊7時，則彈簧加載 之靴掌1 5彈性加壓至子板。 在焊接點相當之堆疊厚度之任何不希望之局部增量 是有效的預防了，其因預漬片1 2不會干擾點熔接。相 反地，其之作動如一有用之間隔。 事實上，更可自第6圖中明白的看出，連接焊墊6和7 之相對表面上凝固之焊料合金1 9之厚度恰好塡滿其間 之間隙，此間隙是較小於預漬片1 2之厚度。 在點焊區域中多層堆疊局部增加厚度之風險可進一 步降低及實際避開，可由將焊墊7之圖案作成穿透孔不 是在每子板之兩個表面上（最終除了是在最低之子板之 外）而是僅在子板（其要來面對下面的子板）之表面上，如 此實現如第7圖中描述之焊接。 至少在有孔穿透之焊墊7之案例中，每個子板之上面 表面上亦設有金屬墊以避免丨谷化合金不當的聚積在金 -11- 506243 五、發明説明（1Q ) 屬墊面積的上面，而不是落下至孔中及塡充在相對金屬 焊墊間之間隙中，如此建立一滿意之機械結合於最後堆 疊之子板與下面平於之子板（先前堆疊的）之間。事實 上，熔化合金不會弄濕亦不會緊結其本身至子板之玻璃 纖維強化內心。 當全部子板己堆疊及焊接在一起時，則操作員就可毫 無阻礙的將多層堆疊自樣板取下，並轉移如此預束縛之 堆疊至壓機之平台之間。 在很多案例中，可以方便地預緊結一預漬片在最底子 板之下面表面上及在待堆疊之最後子板之上面表面上， 並加壓整個總成。 同樣，熟練本技術之人士將易於領會，設若印刷電路 子板3己遭受到加強之銅表面氧化，已知是有利於增進 預漬片之樹脂之黏著，則可有必要首先將焊墊6及7之 表面去氧化，其因氧化之銅不是容易被熔化合金沾濕。 但是即使如此，去氧化可由使用其中含有適宜酸性焊劑 之中空錫合金焊料線而可靠地獲致，即使在銅焊墊之氧 化表面上亦能夠達成有機械強度之焊接。 符號說明 1 ...基礎樣板 2.. .對準栓釘，銷釘 3…子板 4…周邊部分 5.. ·.對準孔 -12- 506243 五、發明説明（11 ) 6，7 ...焊接墊，焊墊 8.. .銅環，銅層 9 ...玻璃纖維強化樹脂板 10.. .小孔 1 1 ··.孔 12.. .預漬片 1 3…缺口 14.. .對準孔 15…靴掌 16.. .焊接烙鐵 16.. .自動桿接單元，公用電焊接元件 1 7 ...金屬細線’焊料合金線 1 8 ...公用系統，旋臂，設置 19.. .凝固之焊料合金506243 V. Description of the Invention (1) Field of the Invention The present invention relates to general printed circuits, and in particular, to a method for manufacturing a multilayer printed circuit board and a method for stacking together and preliminary joining the daughter boards (or auxiliary boards) constituting it. machine. BACKGROUND OF THE INVENTION The integration of printed circuits has been increasing, leading to the realization of printed circuits formed on multilayer boards. This multilayer board consists of several pre-patterned sub-boards, each of which contains a part of the circuit, and is finally hot pressed together to form a "monolithic" multilayer board. This multilayer board is manufactured by alternately stacking pre-patterned daughter boards and glass fiber reinforced plastic front sheets (pre-stained sheets), and hot-pressing the multilayer stack thus constructed. During this stacking and hot pressing, the resin impregnated on the prepreg melts and / or polymerizes and joins the daughter boards together, and in addition isolates the surface of the patterned metal layer of the opposite daughter boards. Because it is highly integrated, the stacking of daughter boards must be extremely accurate. In fact, an alignment error of more than several millimeters (m) will cause misalignment of the interconnect vias between the daughter boards. So the boards must be stacked in an extremely precise manner and must be perfectly aligned during hot pressing. Usually the daughter boards and prepregs are provided with holes in the defined positions to stack them correctly. There are at least two such alignment holes, but there may be many, and these alignment holes are used to stack daughter boards and pre-stained sheets on parallel pins of the template. A typical template, as described in the example in Figure 1, is composed of a copper plate 1 with alignment pins or pins 2 standing on it, which is often kept precise and displaceable and can be blocked to match the stack 506243. 5. Description of the invention (2) the needs of the platform. According to the known method of manufacturing multilayer printed circuit boards, the daughter board and the pre-stained sheet are stacked on the studs. As mentioned above, the final top plate is added with a terminal steel plate, similar to the daughter board and the pre-stained sheet. The holes pass through the ends of the alignment pegs protruding from the stack. The stack, including the plate and the top plate, is transferred to a press for hot pressing. After hot pressing, the multilayer board slides out of the alignment peg of the stacking fixture. This method can prevent any accidental misalignment of the stacked layers during hot pressing, but it is necessary that both the template and the terminal plate appear between the pressing platforms of the press to have a considerable thickness (not less than 100%). This limits the available space between the platforms of the press and the total number of reforming stacks that can be hot-pressed at the same time. Furthermore, it is difficult to separate the steel plate and the multilayer plate on the self-aligning studs due to the tendency of the molten resin to intrude into the alignment holes and to “tighten” the multilayer stack and the steel plate by the studs during solidification. Recently, alternative technologies have been developed to overcome the disadvantages of the two steel plates carried on the press and the need to eliminate the resin residue on the pegs after each press. These technologies are based on the use of metal or thermoplastic resins or the use of heated punches for spot melting to receive pressurized multilayer stacks. This discussion is to tie the stacked layers together so that processing and transfer to the press are allowed without the risk of any misalignment of the stacked layers. The use of nails does not require the use of a template, because the rivet acts as a pin. In the case of two or more peripheral points, point welding, and stacking layers, a stacking template is still required. The heated punch partially melts the -4-506243 on the pre-stained sheet. V. Description of the invention (3) The resin is so adhered to the daughter board and kept stacked together. Once this pre-tightening is performed, the stack can be slid off the alignment pins of the stack template and placed between the platforms of the press. The disadvantage of these techniques of pre-binding the daughter boards together is that they locally increase the thickness of the stack. In the first case, it was due to the inherent rivet head, while in the latter case, it was due to the thermal reflow and condensation of the resin during "point welding". The latter method will further limit the yield, and it takes more than one minute for the stack to be safely handled and placed before the press due to the localized heating and polymerization of the resin. There are also restrictions on the thickness of the stack, which makes it possible to "weld" the use of a heated punch. OBJECTS AND SUMMARY OF THE INVENTION A method for manufacturing a multilayer printed circuit board and a machine for stacking and pre-stressing a daughter board have been found to allow a method of realizing a multilayer printed circuit board to be more efficient than a known method, without improper restrictions The number of stackable layers. According to the present invention, a multi-layer printed circuit board is manufactured by alternately stacking pre-patterned daughter boards and insulating pre-stained boards on the same board, and tightly bonding the layers together to form a stack. Heat and pressure are applied between the platforms of the machine, so that the resin immersed in the pre-stained sheet is refluxed and / or polymerized. The method of the present invention overcomes the disadvantages of the known methods because each daughter board is actually welded to the sub-layer lying flat by inserting a hole in the prepreg. Description of the Invention (4) A soldering pad with a through hole is deliberately formed at the precise formation position of the alignment hole, at least on the lower surface or both sides of each daughter board, except for the first daughter board under the stack . The solder pads, even without any through holes, are formed on at least the upper surface. The pre-stained sheets inserted between the stacked daughter boards are notched or perforated so that they do not overlap on the solder pads adjacent to the daughter boards. It is best that each daughter board has at least two pairs of through-hole pads and the same number of "blind" pads without hole penetration. The best is that the pads of a certain daughter board are arranged so that each of the blind pads faces a perforated pad of a daughter board stacked on the daughter board. According to this embodiment, the pads with hole penetration can be formed only on the surface of each of the daughter boards facing the daughter boards laid flat under the stack. According to another aspect of the present invention, the daughter boards and prepregs are conveniently stacked and joined by using a unique and effective machine. Basically, the machine is composed of a sample plate with multiple alignment pegs and at least a pair of electric welding units, which are automatically moved by an actuator to each of the daughter boards just stacked on another daughter board. The hole penetrating over the pad is used to perform welding and immediately retract and leave the assembled stack to its standby position. This automatic welding unit may also be provided with a device for pressing the daughter board to be welded to a daughter board lying below it during welding. The essence of the method of the present invention is that during assembly of a multilayer stack, each small plate is once soldered to the underlying flat layer once it is placed on top of the stack. This allows the daughter boards to be tightly tied together without any limit on the number of boards. 506243 V. Description of Invention (5). It is known that actual welding can be performed in less than 4 seconds, which can be conveniently performed while the operator's hand can be removed from the stack to pick up another daughter board to be stacked on it. The invention is more precisely defined in the scope of the accompanying patent application. The different viewpoints and benefits of the present invention will become more apparent by referring to the accompanying drawings and referring to the detailed inventions of all the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a template with pegs. Figure 2 is a detailed view of two different types of pads defined on a daughter board. Figure 3 illustrates how to stack daughter boards and pre-stains. Figure 4 illustrates the optimal configuration of two different types of pads. Fig. 5 is an enlarged view describing an automatic welding unit and welding of the machine of the present invention. Figures 6 and 7 describe the welding caused in the multilayer stack of Figure 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT To implement the present invention, a printed circuit board suitable for preparation and an insulating pre-staining sheet suitable for notches or perforations must be in use, as described below. According to the present invention, the machine for stacking and pre-tightening the daughter boards together includes: a base template 1, preferably as described in FIG. 1, which is preferably covered with a layer of steel of insulating material and has upright alignment pairs or bolts Nail 2. In order to adapt the basic template 1 to the stacked daughter boards of different sizes and shapes, the alignment pegs 2 are not fixed, as shown in Figure 506243. 5. Description of the invention (6), but they can be more Convenient installation on slides that can be adjusted and fixed in the desired position, running in the guides defined in the bottom plate of the stacking template. Preferably, the alignment pegs 2 described in Figure 1 will be arranged on the base plate in a non-mirror manner to prevent the daughter board from being installed upside down or turned to the correct stacking orientation of the template. The most preferred is the daughter board 3 as described in FIG. 2. In the center, which is described as a gray tone, is a pattern formed as a printed circuit. The alignment holes 5 and the solder pads 6 and 7 are all formed in the peripheral portion 4, which does not have the appearance of a printed circuit. The peripheral part 4 is only used for the manufacture of this board, and will be trimmed and removed after the multilayer board is heat-pressed. The solder pads 6 and 7 differ in the functional characteristics of their "blind" pads and perforated pads, respectively. However, according to the preferred embodiment, even if the function of the solder pad 6 is to form a "blind" pad, a penetration hole 10 can be conveniently provided to facilitate and create a more efficient soldering. A pad 7 provided with a sufficiently large penetrating hole 11 allows welding to be performed therethrough. The hole Π of the solder pad 7 allows the molten solder alloy to drip through this hole and onto the cymbal pad on which the daughter board is laid flat, so that once solidified, the two daughter boards can be welded together. The blind pad 6 (on which welding occurs) may not have any holes 10 but it is also best to present them with relatively small holes. Although the small hole effectively prevents the molten solder alloy from dripping, it can cause the alloy to adhere to the inner wall of the small hole 10 of the blind pad, so a strengthened anchor will be generated. The pad 7 can be patterned by the copper ring 8 on the glass fiber reinforced resin plate 9 and has 506243. 5. Description of the invention (7) It has a diameter of about 4 to 6 mm outside, and the inner diameter of the center hole 10 is about 2 Up to 3 mm. The blind pads 6 of the same outer diameter can provide a small center hole Π, such as a diameter between 0.8 and 1 leg. From Figure 2, it can be observed that two different types of pads 6 and 7 can also be implemented first on the lowest daughter board of the base template. However, it is considered that the welding is made on a pad having a penetration hole 11 and the lowest daughter board can also be provided with only "肓" pads 6. The way to stack the daughter board 3 and the pre-stained sheet 12 is illustrated in Figure 3. Observation of the diagram clearly shows that: 1) The pre-stained sheet 12 is made with a gap, so that it does not overlap on the periphery of the daughter board 3. On pads 6 and 7 formed in section 4. 2) Each pad 7 in the through hole 11 is pressed and aligned vertically to the blind pad 6 of the daughter board 3 lying below. The pre-stained sheet 12 does not overlap, even if it is partial, the fact that the solder pads 6 and 7 basically cause the molten solder alloy to fall through the holes of the pad 7 to the blind pad 6 pre-stained sheet 12 that can lie flat below With a notch 1 3, corresponding to the solder pad described in the example of Fig. 3, or a hole of a suitable size can be provided. Resin pre-staining sheets 1 2 interposed between various pre-patterned daughter boards 3 in the stack. Its predecessor is an intermediate layer of dielectric glass fiber reinforced plastic. The best production method is to stamp out the rectangular pre-staining sheets. Punch out the alignment holes 14 and the notches 13 (or holes) to correspond to the pads 6 and 7 of the orifice plate 3. If the pad has a diameter other than 4 to 6 nun, these holes in the pre-stained sheet may have a diameter of 506243. V. Description of the invention (8) 10 to 13 diameters. The conditions for alternately aligning the two pads with each other are as described in point 2) above, which is a particularly convenient but not necessary condition to implement the method of the present invention. In fact, it is only necessary to use the solder pads 7 which have holes to penetrate, all of them are aligned vertically and formed on the daughter board 3, except for the lowest daughter board stacked. In this case, once the molten alloy solidifies, it will form a continuous "rivet" extending through the solder alloy throughout the stack. Once all the layers have been stacked on the template, a multi-layer stack is obtained, as described in Figure 4. In its enlarged sectional view, it can be observed that the pads 7 with hole penetration are blind pads 6 aligned perpendicularly to the spaces, which also provide a relatively small meso-hole 10. The automatic welding unit 16 of the machine of the present invention is described in FIG. A common electric welding element 16 is moved by a common system of uniformly rotating spiral arms 18 along a three-degree orthogonal axis, and a wire wire 17 of a solder alloy of tin and silver or copper is passed through the hole of the pad 7 1 1 Welding is performed. This machine can conveniently provide at least one pair of welding units, since each daughter board 3 is to be welded to at least two points. With the command of the operator, the rotary arm 18 moves the electric welding component 16 to the upper hole of the through hole 11 of the pad 7. When the welding is performed, the welding element is moved back to its standby position by the swing arm 18, outside the stack, so as not to interfere with the stacking of another pre-stain sheet 12 and the stacking of another daughter board 3. If each daughter board is to be welded at more than two points (for example, at four points), the machine should be equipped with a second pair of automatic welding units, which is the same as the first pair. -10- 243 243 5. Description of the invention (9 ) Yuan acted simultaneously. The guide arm 18 of the welding unit welding machine can be moved by a pneumatic cylinder. The welding unit 16 may be a general-purpose electric soldering iron using a continuous metal wire, which is a solder alloy wire having a melting point between 250 ° and 310 ° C. The best soldering time is provided with a programmed temperature and soldering time (generally in the range of 150 to 500 degrees Celsius, up to 5 seconds), and automatic solder feeding. Alternatively, as described in FIG. 5, each unit may include a shoe sole 15 for depressing the daughter board to be welded through the entire intervention period of the welding unit. When the unit is lowered to the holed pad 7, the spring-loaded boot 15 is elastically pressurized to the daughter board. Any undesired local increase in the stack thickness at the welding point is effectively prevented, because the pre-staining sheet 12 will not interfere with the spot welding. Instead, it acts as a useful interval. In fact, it can be clearly seen from FIG. 6 that the thickness of the solidified solder alloy 19 on the opposite surfaces of the connecting pads 6 and 7 is exactly the gap between them, which is smaller than the pre-stained sheet 1 Thickness of 2. The risk of locally increasing the thickness of the multilayer stack in the spot welding area can be further reduced and practically avoided. The pattern of the pads 7 can be made through holes not on the two surfaces of each daughter board (except in the lowest daughter board) Outside) but only on the surface of the daughter board (which is to face the lower daughter board), so that the welding as described in FIG. 7 is achieved. At least in the case of the soldering pad 7 with holes, a metal pad is also provided on the upper surface of each daughter board to prevent improper accumulation of grained alloys in gold-11-506243 V. Description of the invention (1Q) belongs to the pad The top of the area, rather than dropping into the hole and filling the gap between the opposing metal pads, thus establishes a satisfactory mechanical bond between the last stacked daughter board and the lower stacked daughter board (previously stacked). In fact, the molten alloy does not wet or cling itself to the glass fiber reinforced core of the daughter board. When all daughter boards have been stacked and welded together, the operator can remove the multi-layer stack from the template without any hindrance and transfer the pre-bound stack to the platform of the press. In many cases, it is convenient to pre-tighten a pre-stained sheet on the lower surface of the bottom daughter board and on the upper surface of the last daughter board to be stacked, and pressurize the entire assembly. Similarly, those skilled in the art will readily appreciate that if the printed circuit board 3 has been subjected to enhanced copper surface oxidation, which is known to be beneficial to the adhesion of the resin of the pre-stained sheet, it may be necessary to first bond the pads 6 and The surface of 7 is deoxidized, because the oxidized copper is not easily wetted by the molten alloy. But even so, deoxidation can be reliably obtained by using a hollow tin alloy solder wire containing a suitable acidic flux, and mechanically strong soldering can be achieved even on the oxidized surface of the copper pad. Explanation of symbols 1 ... Basic template 2 .... Alignment of pins, pins 3 ... Daughter board 4 ... Peripheral parts 5 .. Alignment holes-12-506243 V. Description of the invention (11) 6, 7 ... .Welding pads, pads 8 .. Copper rings, copper layers 9 ... Glass fiber reinforced resin sheet 10. .. Small holes 1 1 ··. Holes 12 .. Pre-stained sheet 1 3 ... Notch 14 .. Alignment hole 15 ... Shoe palm 16 .. Soldering iron 16 .. Automatic rod-connecting unit, common electric welding element 1 7 ... Metal thin wire 'solder alloy wire 1 8 ... Common system, swing arm, setting 19 ... solidified solder alloy