Xiaokang huang, liping zhu, bang nguyen, van tran, harold isom. The phenomena of bowing up, can crack or damage dielectric layers, as well as interrupt the continuity of metal interconnect structures, resulting in yield or reliability problems. Low dielectric materials for microelectronics intechopen. An inter metal dielectric imd fill process includes depositing an insulating nanolaminate barrier layer. Method to solve intermetallic dielectric cracks in integrated. Suppressing methods of cracking on intermetallic silicon. Figure 1 shows an example of a passivation crack at the corner of the top metal foot. Moreover, more of the imd layers will result in more of the electrical characteristic shifts. Inter layer dielectric crack, known as ild crack, is one of the most common fail mode inducing at wire bonding stage. Jul 02, 2015 inter layer dielectric crack, known as ild crack, is one of the most common fail mode inducing at wire bonding stage.
Intermetal dielectric how is intermetal dielectric. These cracks can results in metal migration and functional failures obstacles. E is the electric field caused by the total charge, which includes the free moving and the boun. Dielectric, insulating material or a very poor conductor of electric current. A high inter metal dielectric imd planarization degree is requested in vlsi device manufacturing to avoid process degradation with increasing number of interconnection layers. New solutions for intermetal dielectrics using trimethylsilanebased. Cu wire bonding process induced fail mechanism inter. Corrosion is often a result of many wafer fab or packaging contamination problems. The mechanism of instability on devices characteristics due.
What is difference between dielectric materials and metals. Applications include shallowtrench isolation, premetal dielectric, intermetal dielectric, and passivation. Spinon dielectric materials are used to optimize planarization of interlevel dielectrics in multilevel metal integrated circuit ic designs. Not only is the thermal stability in terms of degradation key, but the insensitivity to thermal history may be just as important.
Metals dielectric constant depends on external electromagnetic field. When using these probes for detecting surface cracks, the perturbation caused to the induced surface current density on the metal plate by the presence of a crack renders its detection and provides information about its dimensions. Reduce rc constant without reducing size r metal interconnect minimized with cu c dielectric need lowk why lowk dielectrics. High dielectric constant materials electrochemical society. In this experiment the main features looked for are cracking, gaps. Metalinsulatormetal mim based capacitors, which are formed by depositing imd films between the lower and upper metal layers, are the typical application in ic areas. In digital circuits, insulating dielectrics separate the conducting parts. The nanolaminate is preferably an oxide liner formed by using an alternating layer deposition process. Jun 01, 2012 interlayer dielectric cracking in back end of line beol stack abstract. The crack stop structure includes a stack layer of alternating insulating and conductive layers and an anchor system extending from the stack layer to a predetermined point below the surface of.
A second metal line overlies the first inter metal dielectric layer and extends along the periphery of the chip. The cracks were initiated at the top corner of aluminum lines, then propagated through the silicon oxide films. Us patent for redeposition high compressive stress pecvd. Many investigations have been conducted by fem simulation 1, 2 or experiments 3, 4. Chamber lids and liners are exposed to plasma during deposition or etch processes requiring a combination of high plasma durability, purity, and dielectric strength.
A dielectric material is an electrical insulator that can be polarized by an applied electric field. D is the electrical displacement, which is related to the electric field caused by the free moving charge the externally added charge. In this paper, several experiments are shown to proof that ultrasonic usg is the most critical factor to induce ic inter layer dielectric ild crack out of wire bonding parameters by physical analysis. It is highly important as when iron and copper pipes are combined, galvanization may take place resulting in corrosion, and eventually, total failure of the pipe system. Its interfacing with the underlying metal layers is also very conformal. Request pdf suppressing methods of cracking on intermetallic silicon oxide. Crack detection with the nearfield openended waveguide or coaxial probes is based on surface current perturbation. However, corrosion can also occur in subsurface al lines that are accessible to moisture by imperfections in its protective glassivation or inter metal dielectric layers. Xiaokang huang, liping zhu, bang nguyen, van tran, harold. Intermetal dielectric imd films between two metal layers are widely used in integrated circuit ic and microelectromechanicalsystems mems devices 15. Cvd processes are also important in strain engineering that uses compressive or tensile stress films to enhance transistor performance through improved conductivity.
Us6162583a method for making intermetal dielectrics imd on. When dielectrics are placed in an electric field, practically no current flows in them because, unlike metals, they have no loosely bound, or free, electrons that may drift through the material. Interlayer dielectric ild cracking mechanisms and their. Spinon dielectrics high planarization for multilevel metal ics. A high dielectric constant, k, means the material exhibits good dielectric behaviour. Supporting information polymermetal organic framework.
High dielectric constant oxides stanford university. Technical barriers and development of cu wirebonding in. A first metal line extends along a periphery of the chip, with a first inter metal dielectric layer on the first metal line. One or more of the layers of imd can be formed in the conventional method. Dcvdapplication premetal dielectricpmd low trapmobile iron lowthermal thermal budget required. But due to limitations in metal lines being applicable for use, research of low. We introduced the first slurries for chemical mechanical planarization of interlayer dielectric ild materials in the early 1980s with systems consisting of highpurity fumed silica abrasives. Sep 18, 2001 a new method is provided for the creation of layers of dielectric that are used for metal stack interconnect layers where the metal stack exceeds five layers. For a low frequency field, metals dielectric constant is a complex, with a very high imaginary part. A new method is provided for the creation of layers of dielectric that are used for metal stack interconnect layers where the metal stack exceeds five layers. This inherent processing of interdielectric ild materials makes thermal stability a key prerequisite of low dielectric materials in microelectronics.
Thus, the extrusion of melted al along the imd cracks, caused metal line bridge. Imd is defined as intermetal dielectric frequently. Low dielectric materials for microelectronics he seung lee, albert. Redeposition high compressive stress pecvd oxide film. The formation of metal seams socalled cracks that result from nonplanar. Gaps between metal lines are filled using high density plasma chemical vapor deposition with a. Interlayer dielectric cmp slurry cabot microelectronics. Highk dielectric materials have recently become important mainly in three areas. Inter layer dielectric crack, known as ild crack, is one of the most common fail.
Metaldielectric band alignment and its implications for metal gate complementary metaloxidesemiconductor technology yeechia yeo,a tsujae king, and chenming hu department of electrical engineering and computer sciences, university of california. However, corrosion can also occur in subsurface al lines that are accessible to moisture by imperfections in its protective glassivation or intermetal dielectric layers. Physical, electrical, and reliability considerations for. In this work an imd planarization process based on the use of spin on glass sog for gap filling followed by sog partial etch back peb is presented. The support, when used, is a lowloss, low dielectric constant material that provides space between the dr and the metal floor.
Dielectric constant, metals, frequency a bit confused. The lowk interlayer dielectric ild materials have low fracture strength due to the presence of pores or other inclusions to reduce the dielectric constant. The layer is highly conformal and is an excellent diffusion barrier. The list of acronyms and abbreviations related to ild inter layer dielectric. Structure, mechanical properties and fracture behavior of organosilicate glass thin films abstract organosilicate glass osg thin films with low permittivity made by means of plasma enhanced chemical vapor deposition are the intermetal insulator in advanced integrated circuits. Due to low adhesion of the dielectric an interfacial crack may occur during fabrication and testing. Method to solve intermetallic dielectric cracks in.
Sog has similar electrical properties with siosub 2 as an intermetal dielectric layer. Once dried, the coated devices were treated at 453 k in vacuum for 4 h. What is the abbreviation for inter layer dielectric. Imd is defined as inter metal dielectric frequently. Interlevel dielectric how is interlevel dielectric. Since silicon nitride has a high dielectric constant, it is not popular as an interlayer dielectric for the simple reason that it results in a high inter metal capacitance. Finally, it can be prepared with very low pinhole density. A method for alleviating the effect of pinhole defects in intermetal dielectric films. We investigated the mechanism of cracking between the interintrametallic dielectric imd silicon oxide films after anneal process.
Dielectricadvanced dielectric cmp polishing slurries. Since the driving force for crack propagation increases with. Interlayer dielectric cracking in back end of line beol stack abstract. Inter metal dielectricimd low voidfree gapfill, somth surface lowprocess temp. We investigated the mechanism of cracking between the inter intrametallic dielectric imd silicon oxide films after anneal process. A method for alleviating the effect of pinhole defects in. Temp, high strength moistureisolation ability requiredarc hardmasksti shallow. Zoughi, a novel microwave method for detection of long surface cracks in metals, ieee transactions on instrumentation and measurement, vol. Copperlowk dielectrics are used in todays ics to enhance electrical performance.
Investigation of the delamination mechanism of the thin. Passivation stress versus top metal profiles by 3d. The positive charges within the dielectric are displaced minutely in the. Characterization and optimization of inorganic spin on glass process. Cu wire bonding process induced fail mechanism inter layer. Ild abbreviation stands for inter layer dielectric.
An intermetal dielectric imd fill process includes depositing an insulating nanolaminate barrier layer. Highpurity alumina al 2 o 3 and aluminum nitride aln are frequently used to meet these equipment challenges. Metaldielectric band alignment and its implications for. Figure 1 shows an example of a passivation crack at the. Why the dielectric constant value of metals is infinity. Microwave and millimetre wave sensors for crack detection. The mechanism of instability on devices characteristics. Oxynit film property normallybetween oxide nitride.
Why is the dielectric constant for metals infinity. Jul 30, 2002 the phenomena of bowing up, can crack or damage dielectric layers, as well as interrupt the continuity of metal interconnect structures, resulting in yield or reliability problems. Aug 14, 2019 a dielectric fitting is specifically designed to join two types of metal pipes together without the need for soldering. Interlayer dielectric cracking in back end of line beol. Lower resistance is accomplished by switching from alcu to cu interconnect and the capacitance is reduced by replacing sio 2 in the inter level and inter metal dielectric layers with lower. Structure, mechanical properties and fracture behavior of. Therefore an overlying, or capping, silicon oxide layer, formed with a high compressive stress, is needed to balance the tensile stress supplied by underlying. A local model of an eightlayer stacked interconnect structure was built in the fea model including the thin dielectric film stacking of the interlayerdielectric ild, etch stop layer esl, intermetaldielectric imd and the usg dielectric material. A stack of five layers of metal interconnect lines contains one layer of intra metal dielectric ild and four layers of inter metal dielectric imd. Us20120074519a1 crack stop structure enhancement of the.
They can be used to significantly improve topside planarity when applied prior to the final passivation step. Jan 20, 2017 a dielectric material is an electrical insulator that can be polarized by an applied electric field. The present invention is a method for making intermetal dielectrics imd on. Us7235864b2 integrated circuit devices, edge seals therefor. Memory chips use the presence or absence of charge in a capacitor.
In this cu wire development study, there are total 7 legs comprising of bare cu wire bonded on fine pitch 64ball bga packages on a 2layer substrate. The shortloop structures consisted of a metal and dielectric stack to mimic the final layer of a typical cmos14 backend stack. This inherent processing of inter dielectric ild materials makes thermal stability a key prerequisite of low dielectric materials in microelectronics. When a dielectric is placed in an electric field, electric charges do not flow through the material as they do in a conductor, but only slightly s. The shift is dominated by the interface state reduction. Spinon dielectric materials are used to optimize planarization of inter level dielectrics in multilevel metal integrated circuit ic designs. High dielectric constant materials as shown in table i, a large variety of materials have been used for a number of applications. Metal line layout design and wafer fabrication process variation should also be. But the most serious problem in logic circuits is now in the fet gate stack, that is the gate electrodeand the dielectric layerbetween the gate and the silicon channel. Applications include shallowtrench isolation, pre metal dielectric, inter metal dielectric, and passivation. A method for alleviating the effect of pinhole defects in inter metal dielectric films. Porous dielectrics in microelectronic wiring applications mdpi. Redeposition high compressive stress pecvd oxide film after.700 1110 861 738 1513 533 1305 646 2 1165 16 199 1508 234 538 1355 656 610 1013 1475 1214 618 1007 914 883 1050 1056 476 67 382 75 957 705 434 899 777 929