外文翻譯--引線鍵合的現(xiàn)狀與發(fā)展趨勢

1、<p><b>　　附錄1</b></p><p>　　WIRE BONDING: PRESENT AND FUTURE TRENDS</p><p><b>　　ABSTRACT</b></p><p>　　Gold wire bonding has been a standard operation inpl

2、astic IC package assembly for several decades. However, as the packages grow larger, thinner, and denser, the capabilitiesof equipment, and of the wire itself, are being taken to thelimit. Recently, specialty wires have

3、been introduced with different dopants and processing procedures giving higherstrength and stiffness. These improved properties can offerbetter wire wash protection as well as capability for longspans and low loops. Disa

4、dvantage</p><p>　　Advances in the wire bonders allow better machinemotion control with precise placement of the wires. Improved control software can produce low loops and long straight spans by simultaneousl

5、y regulating motion along all three axes, from ball placement to the wedge bond on the lead tip. Some manufacturers even believe that all improvements can be achieved through the equipment alone, without having toresort

6、to the specialty wires.</p><p>　　The combination of better wires and better machines should be able to produce the type of wire bonds desired in thin fine pitch plastic packages. Nevertheless, the physical l

7、imits of ball bonding may eventually be reached, if the current trend of finer and finer pitch continues. In this case, other types of interconnection will start looking attractive, such as TAB, flip-chip, or the develop

8、ment of high speed, flexible wedge bonding.</p><p>　　1.0 CURRENT STATUS</p><p>　　The gold (Au) bonding wire generally used in the industry for automated thermosonic bonding is primarily berylliu

9、m (Be) doped, at about 3 to 8 parts-per-million (ppm). In this range, beryllium gives the wire increased strength by precipitation hardening in the matrix of the intermetallics formed from the two elements. It also allow

10、s the gold to be more easily drawn, as very pure gold is too soft for shaping into a fine wire (1,2). Stronger and harder wires have been introduced into the market re</p><p>　　While adequate for most plasti

11、c packaging bonding needs, the previous generation of bonders do not have the ability to bond accurately for the next generation of high density packages. These machines tend to have analog motion control, which does no

12、t lend to precise travel and placement of the wires. Also, being analog, each machine is unique with respect to its set-up. Parameters optimized on one bonder cannot easily be transferred to another.</p><p>

13、　　2.0 TRENDS IN GOLD BONDING WIRE</p><p>　　2.1 MATERIAL REFINEMENTS</p><p>　　Table 1 compares the properties of some typical commercially available wires. Generally all the “new” wires</p>

14、<p>　　have improved properties, such as greater breaking load,lower loop height, and increased pull and shear strengths.</p><p>　　Dopants increase the strength of Au wires. Forinstance, Be increases g

15、rain refinement and strength by introducing intermetallic precipitates, since it is a small atom compared to gold and is electronically issimilar. Even in minute amounts, the atoms will distort the lattice, making Be an

16、effective hardening agent. This is currently the primary dopant used in the industry. However, increasing the amount to above 12 ppm will cause Be to come out of solution, and induce intergranular fracture duri</p>

17、<p>　　Other metals are also used to maximize mechanical properties. Silver (Ag), palladium (Pd), copper (Cu), and platinum (Pt) are added for solid solution strengthening and chemical stability. Three of the four

18、elements cited are in the same group in the periodic table as gold. In addition, just aswith gold, all four elements are face centered cubic (FCC)with similar lattice constants and electronic structure.</p><p&

19、gt;　　Strengthening is by substitution of lattice atoms with dopant atoms to provide the chemical stability (4). Other metals, like calcium and lanthanum, can also be used for strengthening by precipitation hardening, in

20、 much the same manner as Be. In addition to the dopants, the production process also influences the wire properties. Careful rolling, annealing, and drawing improve the wire properties by insuring grain uniformity and ev

21、en dispersion of the precipitates (1).</p><p>　　2.2 LOWLOOPING CHARACERISTICS</p><p>　　Another purpose for these refinements is to increase strength and hardness and to reduce the length of the

22、heat affected zone (HAZ). The HAZ is the location where the loop is formed, and should ideally be between 25 pm to 100 pm from the ball bond. Through recrystallization and grain growth, the HAZ can easily be deformed. La

23、rger grains are generally weaker from a lack of dislocations due to work hardening. Opant precipitates tie up the grain boundaries during heating and prevent grain growth. O</p><p>　　2.3LONG SPAN CHARACERIST

24、ICS</p><p>　　As the wire spanfrom the bond pads on thechip to the lead fingersincreases, the risk of wiresagging, and sweepingduring molding also grows.calcium and lanthanum, can also be used for strengtheni

25、ng byprecipitation hardening, in much the same manner as Be. Inaddition to the dopants, the production process also influencesthe wire properties. Careful rolling, annealing, and drawingimprove the wire properties by ins

26、uring grain uniformity andeven dispersion of the precipitates (1).</p><p>　　Figure 2 shows how the mold flow affects wire washing (8a). &I. is the ratio of the amount of wire deflection,6, over the bond

27、pad pitch s. Thus, if 6"s is equal to 1, the wire bond has draped over to the adjacent pad. This ratio is used as a metric for describing the extent of wire sweep in a package. In practice, however, sweep is defined

28、 as any deformation that exceeds a ratio specified by the IC manufacturer. Typically, this value could be from one to three wire diameters depending on the as</p><p>　　As thefront velocity of the molding enc

29、apsulant is increased, higher flow-induced forces are observed resulting in more sweep.To withstand the mold compound flow, the Au wire must be stronger. The increased strength and stiffness of the specialty wires, indic

30、ated by the high breaking load and elongation values, provide more resistance to mold sweep.Table 2 compares the typical sweep observed between the</p><p>　　standard wires and the newer high-strength wires f

31、or different wire spans. The same refinements which give the Au specialty wires low looping capabililities also provide the means for long spans.It should be pointed out that wire sweep results from a combination of fact

32、ors such as mold cavity design, molding parameters, and device layout (8b,c). These factors control the extent of sweep just as much as the properties of the wires and the profiles of the bonds. Thus, in order to reduce

33、or elimina</p><p>　　3.0 OTHER WIRE MATERIALS</p><p>　　Placing a non-electrically conductive polymer coating on the Au wire is an attractive option becausewires could wash without shorting. Such

34、coating can be rather thin (in the micron range) and can be made from a number of different polymer bases such as epoxies, acrylates, or urethanes. The difficult task comes in finding a coating which will not affect bond

35、ing. Although the flame bums the coating during ball formation, residues tend to collect over time, and accumulate at the capillary tip. Smo</p><p>　　3.1 COPPER WIRF</p><p>　　Other metals are al

36、so being evaluated, mainly for cost savings, but also for increased strength. One of the primary candidates is copper, due to its high strength at high purity and lower cost than gold, as listed in Table3. The greater st

37、rength is an advantage in reducing wire wash during molding (9). Copper wire might also allow direct bonding to bare copper, eliminating the precious metal plating (e.g., Ag or Au) on thelead fingers and further reducing

38、 cost(10).</p><p>　　However, the typical drawbacks of copper bond wireare a higher bonding temperature (3OoOC vs. 20O0C), ablanket gas shroud to prevent oxidation (Hm2 or Arblanket), and bond cratering conce

39、rns. With respect to thelatter, for instance, since copper wires are harder than goldwires, more force is needed to bond to the pads, causingpotential cracking of the &Je&c underlayer. A hard barriermetal may eve

40、n be needed for the bond pa& to absorb theof the capillary (9). &though the rate of intermetallicnom </p><p>　　3.2 ALUMINUM WIRES</p><p>　　Aluminum alloy wires, which are extensively use

41、d in hermetic assembly, have been tried for plastic packages. However, intergranular corrosion of AI-Mg wire after autoclave (1 1) and material problems such as ball porosity (12) have hindered further development. Alumi

42、num wires are softer than the gold counteqm. As a result, for the same wire diameters, more wire sweep will be observed during molding of devices with bonded aluminum wires, Since aluminum has a lighm density than gold,

43、the extent of</p><p>　　4.0 EVALUATION OF EQUIMPENT IMPROVMENT</p><p>　　4.1 EQWMEEIWXEMEUS</p><p>　　The newest generation of wire bonders have digital motion control. The machines ar

44、e calibrated to a standard and the inaccuracy in the X-Y table are mapped against a known reference. The machines become essentially transparent to the user and the control software for machine settings are interchangeab

45、le. With the previous generation of machines, each unit was essentially unique. A bonding program created on</p><p>　　one bonder could be used on another machine only after modification. Thus, it is difficul

46、t to maintain product consistency current generation of machines such as the K&S 1484XQ, programs are fully transferable Once all the bonders in a Work cell are calibrated to a indard.</p><p>　　Furtherm

47、ore, the newer machines are faster and more accurate, requiring less set-up time when product changes are that can be configured “on the fly”, except for the Placement Of the hard tooling specific to a particular h ” e .

48、 This is an important feature With the arrival Of Small lots, wider leadframe widths, diverse package portfolios, and the requirement for quick time .</p><p>　　Another important feature, found in the previou

49、sgeneration, is the pattem recognition system (PRS) used foraccurate die and leadframe alignment. These systems have been improved and now include the ability to locate the exact center of the bond pads. This automatic t

50、argeting is vital when programming the wire layout on a fine pitch device. As bond pads continue to shrink, there is little room for bond placement error. Additionally, the newest PRS can locate the narrow lead tips foun

51、d in PQFP (Pl</p><p>　　While ball bonders dominate the fine pitch high speed gold wire bonding arena, wedge bonders hold otherdistinct advantages. The formed wedge bond is much narrower in width than a ball

52、bond formed from the same wire. This reduced bond size will facilitate the continuing decrease in bond pad pitch. The wire loop formed by the Thiswould be-bkneficial for use in thin packages. The major drawback of wedge

53、bonding is the requirement to rotate the bond head or work holder, the latter being impractical </p><p>　　Still other improvements result from a change in analog to digital controls. An example is an increme

54、ntal motor-driven bond head versus the older spring-controlled bond head. The spring wears out with time and is affected by temperature changes and temper quality. With the digital controllers, not only can the position

55、of the bond head be monitored, but also its velocity and acceleration (3). More importantly, under digital control, all three axes of motion can be coordinated to a higher degree </p><p>　　Another recent tre

56、nd is the physical connection of three or four wire bonders with one die attach machine forming an automated in-line production work cell. Along with the physical connection, there is a communication link which is used f

57、or tasks such as scheduling and collection of production statistics.</p><p>　　There is also a trend with some machine manufacturers to add on process monitoring gear, which measures certain bonding parameter

58、s in real time. In this way, incipient problems can be detected and corrected before out-of-spec products are mass produced. It may no longer be viable to simply stop the machine when scrap is being generated, but rather

59、 to anticipate, and even correct bonding problems without operator intervention.</p><p>　　4.2 LONG SPAN AND LOW LOOP CAPABILITY</p><p>　　Several factors can affect what are considered low loops.

60、 Interpretation of the loop height is subjective,depending on the observer point of measurement. On the more objective side, in addition to the type of wire used, leadframe tolerances, die backgrinding tolerances, die at

61、tach height variation, die placement variation, wire bonder capability, and leadframe handling are all considerations. For instance, with low loops, the wire is stretched taut and any wedge bonding Drocess is also inher

62、ent</p><p>　　Optimization of the gold wire for automatic bonders may still be lacking due to an incomplete understanding of the relationship between the mechanical properties and the bonding performance. How

63、ever, this is not a universally held premise (14). Wire bonder manufacturers, of course, would like to believe that software enhancement in the capillary travel trajectory can accomplish low looping and long span.</p&

64、gt;<p>　　Material issues become second order effects. On the other hand, some wire vendors think that the lowest loop height and greatest span length can be obtained with specialty wires. In reality, such results

65、would be obtained through the synergistic interaction of improved doped wires and enhanced wire bonder capabilities.</p><p>　　Multiple types of loop shapes can be formed on the newer machines thanks to digit

66、al controls. Figure 3 shows some examples of the different loop shapes possible with standard wires. </p><p>　　In terms of long spans, the straightness depends on the machine control, on the amount of residu

67、al stress remaining in the wire from the winding process, and on the inherent strength of the wire itself. The more precisely the bond head can move between the pad and the lead finger, the straighter the wire will be wi

68、thout sagging. Most of the new equipment software can now readily provide such capability.</p><p>　　However, the final shape of the wires is actually determined by the molding process. Assuming that molding

69、is well optimized for a given packz.ge, the wire configuration and properties are the only two factors left governing the final extent of sweep. This is where the specialty wires can become a factor, as higher strength a

70、nd stiffness provide better resistance to flow-induced deformation.</p><p>　　5.0RELIABILITY OUESTION</p><p>　　Certain manufacturers have employed rather exotic elements in the initial formulati

71、ons of specialty wires, in an effort to obtain the required material properties. However, when the ball is formed, sometimes a void is created at the base of certain wires. This is caused by the change in dopant solubili

72、ty from liquid to solid and zone solidification of the ball. The main concern is reduction of the contact area to the pad, resulting in reduced bond adhesion and bond strength.Furthermore, the long</p><p>　　

73、Already, the limits of thermosonic bonding are being approached with 100 pm (4 mil) pitch as the current standard, as illustrated in Figure 4. At this stage, the physical limitations include the passivation opening on th

74、e pad and the diameter of the capillary tip. Some increase in density can be achieved through smaller pads, thinner wires, and lower loops, but other processes may be needed in the future. (16). For instance, with the st

75、andard 4 to 5 mil square bond pad, the passivation lip cover</p><p>　　6.0FUTURE DEVELOPMENT</p><p>　　6.1 GOLD WEDGE BONDING</p><p>　　Gold wedge bonding is one possibility. Pitches

76、half of those for ball bonding are possible. However, some mechanical adaptations are required before wedge bonding can be applied to plastic packages. Due to the nature of the process, the die must be rotated to all fou

77、r sides for bonding. This limitation has not been an issue with hermetic packages, since bonding is carried on one single isolated unit at a time. The bonding head is stationary while the workholder is rotated. On the ot

78、her hand, pla</p><p><b>　　附錄2</b></p><p>　　引線鍵合的現(xiàn)狀與發(fā)展趨勢</p><p>　　摘要：引線鍵合在IC集成電路封裝中作為一種標(biāo)準(zhǔn)的操作已經(jīng)很多年了，但是隨著封裝模模越來越大，間距越來越小，密度越來越大，設(shè)備各引線的能力已經(jīng)達(dá)到了極限。最近為了滿足高強(qiáng)度和剛度的要求，滲入不同物質(zhì)和不同加工過

79、程的特殊引線問世，這些提高的性能能夠提供很好的失線保護(hù)，也能滿足大間距和低線高的要求，缺點(diǎn)是成本較高，滲入大量其它物質(zhì)的潛在可靠性問題等。</p><p>　　引線鍵合的發(fā)展要求要有較好的引線準(zhǔn)確定位的機(jī)械運(yùn)動控制，先進(jìn)的軟件控制，通過實時的控制各軸的運(yùn)動來達(dá)到低線高各長直線距的要求從熔球的定位，到引角的楔焊。有些生產(chǎn)商甚至認(rèn)為所有的提高都可以通過改時設(shè)備本身來達(dá)到，而不必采用特殊的引線</p>&

80、lt;p>　　較好的引線各先進(jìn)的設(shè)備的結(jié)合應(yīng)該有夠得到在細(xì)間距封裝過程中所分需要的那種引線鍵合，但是如果當(dāng)前的越來越細(xì)的間距的發(fā)展趨勢繼續(xù)，球焊引線的物質(zhì)的限制可能最終達(dá)到極限，在這種情況下其它類型的內(nèi)部聯(lián)接方式將具有吸引力，如TAB，倒裝芯片和高速自由楔焊的發(fā)展。</p><p><b>　　1.0現(xiàn)狀</b></p><p>　　用在自動熱超聲鍵合工業(yè)中的金

81、絲引線鍵合，引線中主要滲入大約百萬分之三到八的Be，在這個范圍內(nèi)Be通過加速兩金屬所成鍵的形成，增加了引線的強(qiáng)度，加入Be更有利金的的位伸，因為太純的金由于太軟很難制成細(xì)絲。為滿足細(xì)間距各大的跨度的要求，高強(qiáng)求度的引線已經(jīng)問世，這些引線也補(bǔ)設(shè)計制造成滿足薄芯片封裝中的低線高要求。 </p><p>　　為了充分滿足大部分集成電路封裝的有需要，前一代的引線鍵合工藝，無法滿足下一代所要求的高密度封裝的能力。這些設(shè)備

82、都有類似的運(yùn)動控制，這些運(yùn)動控制無法達(dá)到引線準(zhǔn)確運(yùn)動和定位的要求，同時由于類似，每個設(shè)備的安裝都是不同的，在一個鍵全機(jī)上優(yōu)化的數(shù)不能輕易的被轉(zhuǎn)移到另一個鍵合機(jī)上。</p><p>　　2.0金絲引線鍵合的發(fā)展趨勢</p><p>　　表1對現(xiàn)有的一些引線的性能作了比較，其它金屬也被用來增加引線的機(jī)械性能，為了增加兩金屬間的結(jié)合強(qiáng)度各化學(xué)穩(wěn)定性，而加入了Ag,Pd,Cu,Pt被列舉的3/4的

83、元素類元素周期表中與金在同一族，另外象金一樣另外4種元素所形成的晶粒都是中心對稱的，原子核外電子有類似的結(jié)構(gòu)。通過與滲入的元素形成更牢固的離子鍵，從而提高了化學(xué)穩(wěn)定性。別的一些元素像鈣、鑭等也被用來像Be一樣通過加速硬化而提高強(qiáng)度。除了滲入其它元素，引線的加工過程也影響引線的性能。精心的纏繞，退火，拉伸可能通過確保晶粒的完整和分布的均勻來提高引線的性能。</p><p><b>　　2.2低線高的特點(diǎn)&

84、lt;/b></p><p>　　精細(xì)加工的另一個目的是增加強(qiáng)度硬度各減小熱影響區(qū)的長度（HAZ），熱影響區(qū)就是引線彎曲的位置，理論上在離球焊焊點(diǎn)25微米到100微米左右通過得結(jié)晶各晶粒的增長，熱影響區(qū)很容易彎曲，大的晶粒一由于工作硬化而缺少斷層，因而一般強(qiáng)度較低，滲入的物質(zhì)通過在加熱過程中包圍晶粒的邊界而阻止晶粒的生長。滲入大量其它物質(zhì)的一個原因是確保在粒格中有足夠的剩余物質(zhì)，因此要想得到好的線彎能力就要

85、很好的控制熱影響區(qū)</p><p>　　圖1描述了一種標(biāo)準(zhǔn)金絲引線成球后的硬度變化曲線。在2gm的載荷下，從金絲的勁部向焊點(diǎn)測量，曲線呈U型，在離球焊一段距離處有一個最小值。引線在硬度最小處彎曲，這個位置一般是在熱影響區(qū)的中心，這個位置是曲率最大的位置，影響線高.縮短熱影響區(qū)的長度可能降低線高，圖中A線硬度高，熱影響區(qū)比B線更靠近勁部，從而得到較低的線高。</p><p><b>

86、;　　2.3大跨度的特點(diǎn)</b></p><p>　　隨著引角與焊盤間的距離越來越大，在鍵合過程中引線的下垂和失線的危險越來越大，圖2顯示了引鍵合過程對失線的影響， 引線的彎曲程度與引線跨度的比，這個比值用來描述在封裝過程中引線下垂的程度。然而，實際上引線下垂的定義指任何超過生產(chǎn)商所指定的比值的彎曲。一般情況下這個值等于1到3個引線的直徑，這要由生產(chǎn)商的集成設(shè)計過程確定。俯視圖指明了實驗設(shè)備上引線的位

87、置，也闡明了由位置數(shù)據(jù)點(diǎn)所描述的角度。隨著前端封裝速度的加快，在拉弧過程中所產(chǎn)生的力也越來越大，從而導(dǎo)致了更多的引線下垂。</p><p>　　要想經(jīng)受住這這些作用而不下垂，金絲必須更加堅韌。由高的后斷力和延長值所表現(xiàn)來的特種引線的強(qiáng)度和剛度能夠更好的抵抗引線下垂。表2比較了標(biāo)準(zhǔn)引線和新出現(xiàn)的高強(qiáng)度引線在不同間距下的典型的引線下垂。在相同的工藝下金的特種引線的低線弧能力讓大家看到了大跨度引線鍵合的希望。</

88、p><p>　　需要指出的是引線下垂是多種因素共同作作的結(jié)果，這些因素包括澆鑄空洞水平，成形參數(shù)和設(shè)備規(guī)劃等。這些因素與引線的加工工藝和引角的形狀一樣響影著引線的下垂。然而想要降低或是徹底消除成形所導(dǎo)致的引線下垂要考慮很我方面的問題。</p><p><b>　　3.0其它引線材料</b></p><p>　　在金絲表面鍍一屋不導(dǎo)電的物質(zhì)是一種很吸

89、引人的選擇，因為這樣在失線時不會導(dǎo)致短路。這種鍍層可以很薄甚至達(dá)到微米級，可能采用各種聚合物制造，如：環(huán)氧樹脂，聚氨酯橡膠，丙烯酸脂。困難在于要找一種不影響引線鍵合的的物質(zhì)很難。雖然在成球過程中鍍層被融掉，但是隨著時間的推移剩余的鍍層物質(zhì)會積聚在細(xì)小的引腳上。開始影響引線的順利傳導(dǎo)，最終傳導(dǎo)被阻塞。更嚴(yán)重的問題出在楔焊時。在這個階段引線與引腳的接觸只能通過超聲運(yùn)動。鍍層在引線與引角接觸時被摩擦掉，。自然任何剩余的鍍層物質(zhì)都會影響接觸區(qū)域

90、和鍵合質(zhì)量。到目前為止這兩個問題仍然沒有被解決。鍍層引線還沒有用于商業(yè)領(lǐng)域。</p><p><b>　　3.1銅引線</b></p><p>　　考慮其它的的金屬材料主要是為了不用鍍層，同時也是為了增加強(qiáng)度。其中考慮較多的之一是銅，表3中展示了銅在高純度下的高強(qiáng)度以及它的低成本。高強(qiáng)度避免了在鍵合過程中的失線。銅引線可以直接與裸露的銅制引腳鍵合，從而不用在引角上鍍層

91、，盡一步低了成本。</p><p>　　但是銅引線鍵合的主要問題是要求較高的鍵合溫度，要使用保護(hù)氣阻止氧化以及鍵合點(diǎn)的陷入程度。例如后者由于銅比金硬度大，在鍵合時需要更大的力，可能導(dǎo)致襯層的斷裂。引腳需要使用強(qiáng)度更高的材料來抵消劈刀的沖擊力。</p><p>　　但是銅引線主要的缺點(diǎn)是要求校高的鍵合溫度，要使用保護(hù)氣來阻止銅被氧化以及焊點(diǎn)陷入問題。例如像后者由于銅絲的硬度比金絲的高，因些在

92、鍵合時要對焊盤施加更大的力</p><p>　　從而可能導(dǎo)致底襯的斷裂。焊盤需要使用更硬的材料來抵擋劈刀的沖擊，雖然Cu Al間的擴(kuò)散程度沒有Au,Al的好，但是商業(yè)領(lǐng)域仍然愿意采用銅引線鍵合。這主要是觀念問題，盡管小規(guī)模的實驗證實銅絲與金絲可靠性差不多。</p><p><b>　　3.2鋁合金引線</b></p><p>　　被廣泛的應(yīng)用于

93、真空集成中的鋁合金引線已經(jīng)被嘗試用于塑料封裝中，但是高壓放電后的ALMG引線的融合問題和像融球孔洞這樣的材料問題已經(jīng)阻止了它 進(jìn)一步發(fā)展，由于鋁絲比相應(yīng)的金絲軟，在要同的直徑下鋁絲比金絲將更容易產(chǎn)生引線下垂的問題。由于鋁絲的密度比金絲的小，用X射線失效分析技術(shù)很難評價，因為鋁絲的反射效果不好，對X射線來說可能是“透明的“。在這種情況下開瓶是測量引線下垂的惟一方法.</p><p><b>　　3.3金合

94、金引線</b></p><p>　　金全金引線由于具有較高的引線強(qiáng)度而被關(guān)注。但是可靠性問題和消費(fèi)者的認(rèn)可矢口否認(rèn)可程度是兩個主要的問題。由于摻入其它金屬而導(dǎo)致的金屬間的增長和焊點(diǎn)的陷入問題也是擺在它面前的障礙。</p><p>　　4.0設(shè)備改進(jìn)的評價</p><p><b>　　4.1設(shè)備改進(jìn)</b></p>&l

95、t;p>　　最新一代的引線鍵合機(jī)采用數(shù)控技術(shù)控制運(yùn)動。機(jī)器被設(shè)定為標(biāo)準(zhǔn)形式，XY坐標(biāo)的錯誤在同一參考系下標(biāo)定，機(jī)器對用戶來說是完全透明的，機(jī)器設(shè)定的控制軟件是可以互換的。前一代的機(jī)器本一個單元本制質(zhì)上都是獨(dú)立的，用于一臺鍵合機(jī)上的程序只能被修改后才能用于另一臺機(jī)器上，。因此很難保證在一個工作組里的所有鍵合機(jī)的產(chǎn)品的連續(xù)性。幸運(yùn)的是現(xiàn)在這一代鍵合機(jī)只要在一個工作組里的所有鍵合機(jī)用同一個標(biāo)準(zhǔn)設(shè)定，程序是完全可以移植的。 </

96、p><p>　　而且新一代的鍵合機(jī)速度更快，精度更高，當(dāng)產(chǎn)品改變時需要更少的安裝時間。大部分模型包括可編程的工作夾具，這些位置可以隨時定位，除了對一些特殊芯片的特殊要求。這是小范圍，大跨度，多樣式以及要求快速循環(huán)時間到來的一個重要特點(diǎn)。</p><p>　　在前一代種的一個重要特點(diǎn)是用于芯片精定位的格式識別系統(tǒng)，這些系統(tǒng)已經(jīng)被進(jìn)一獲步的改進(jìn)，現(xiàn)在已經(jīng)具有準(zhǔn)確識別焊點(diǎn)中心的能力。當(dāng)對細(xì)間距的微小

97、芯片進(jìn)行編程時這種自動目標(biāo)識別是很重要的，由于芯片小因此幾乎不充許定位錯誤。另外最新的prs能夠定位很窄的引腳，將第二個引腳的位置準(zhǔn)確而迅速的定位在中心。未來的發(fā)展方向主要是能夠完全的自動學(xué)習(xí)過程，從而消除操作錯誤。</p><p>　　球焊主導(dǎo)高速高精度領(lǐng)域的同時，楔焊也在其它領(lǐng)域表現(xiàn)出了其獨(dú)特優(yōu)勢。由楔焊所形成的焊點(diǎn)比用同種引線球焊所形成的焊點(diǎn)心寸小。這種優(yōu)點(diǎn)可以進(jìn)一步的減小焊點(diǎn)的尺寸從而適應(yīng)細(xì)間距的要求。由

98、楔焊所形成的線弧高度比球焊更低，這在薄的芯片封裝中很有用。</p><p>　　楔焊的主要不足之處在于要不斷的更換鍵合頭或夾具，但后者對剝光的芯片來說是不現(xiàn)實的。而且現(xiàn)有的楔焊鍵合機(jī)與球焊相比速度校低，但這種情況隨著新一代高速楔焊的問世將得到必變。</p><p>　　數(shù)字控制也導(dǎo)致了其它改進(jìn)。一個例子便是馬達(dá)驅(qū)動的鍵合頭取代了以前的彈簧控制的鍵合頭。彈簧隨著時間的推移會松遲，也很容易受溫

99、度改變和回火質(zhì)量的影響。利用數(shù)字控制器不僅可以監(jiān)控鍵合頭的位置，而且可以監(jiān)控它的速度各加速度。更重要的是在數(shù)控的條件下三個運(yùn)動軸可以以很高的精度運(yùn)動。這樣使更精確的運(yùn)動控制和低線弧高度以及統(tǒng)一的線弧形狀成為可能，表4將最新一代的機(jī)器的一些參數(shù)與上一代做了一些比較。</p><p>　　最近的另一種趨勢是將幾臺鍵合機(jī)聯(lián)接起來組成一個工作單元。除了硬件的聯(lián)系，還有一個實現(xiàn)時間安排和產(chǎn)品數(shù)據(jù)統(tǒng)計的交流平臺。</p