Reduce the deposit of resistor of semiconductor metal thread and quarter corrode technology
[introduction] system structure, interstitial bulk, crystal boundary and material interface break resistor rate You Jijing of copper match a decision, follow measure is narrow and remarkable promotion. Normally, the making flow of copper cash is to use groove to engrave corrode craft to be in low interpose report cuts corrode groove figure in 2 oxidation silicon, use cupreous fill groove through Damascus flow next. But the much crystal structure that this kind of method can give birth to to contain apparent crystal boundary and space, increase copper cash resistance thereby. To prevent Damascus anneal craft medium copper diffuses, this craft still used the nitrogen that tall resistor leads to turn tantalum liner material.
Summary: Use SEMulator3D? Can inspect sexual deposit and thread of metal of research of quarter corrode function workmanship, realize resistor reduce considerably
01 introductions
System structure, interstitial bulk, crystal boundary and material interface break resistor rate You Jijing of copper match a decision, follow measure is narrow and remarkable promotion. Normally, the making flow of copper cash is to use groove to engrave corrode craft to be in low interpose report cuts corrode groove figure in 2 oxidation silicon, use cupreous fill groove through Damascus flow next. But the much crystal structure that this kind of method can give birth to to contain apparent crystal boundary and space, increase copper cash resistance thereby. To prevent Damascus anneal craft medium copper diffuses, this craft still used the nitrogen that tall resistor leads to turn tantalum liner material.
We can use deposit of physical gas phase (PVD) with the copper of 10 deposit of high kinetic energy to 100 electron volt, get resistance the single crystal structure with low, high density. But the confine of PVD is comparing difference at enclothing a gender, and can go up in plane only even deposit, cannot use at fill deep aperture or groove (graph 1a) .
Want to get independent metallic line, need to be on plane above all deposit and even copper layer, use ion subsequently bundle undertake physics engraves corrode. Copper and active gas do not produce volatile compound, because this cannot use reaction ion,engrave corrode craft. If an angle of incidence is very high, ionic bundle of quarter corrode (the acceleration of the generation in IBE) argon ion is OK purify copper. But the keep out effect as a result of structure of film of attack by surprise, the district that can carve corrode will suffer be restricted. Graph 1b was revealed when film of attack by surprise perpendicular at incident ion bundle when cannot carve corrode district (gules) , the place of suffocate suffocate of atomic eject method that brings about as a result of keep out of film of attack by surprise causes this. When film of attack by surprise and ionic method parallel, all area that were not covered can be engraved corrode. Accordingly, the film of line form attack by surprise that IBE is confined to length of quarter corrode random.
02 technology measure and fictitious workmanship
To see deposit and the quarter corrode effect to line resistor, do we use SEMulator3D? Can inspect sexual deposit and PVD of imitate of quarter corrode function and IBE craft. SEMulator3D of have the aid of, we use 30 ° dispersive part can inspect PVD of emersion of sexual deposit craft, accurate imitate gives this flow to with a bang hit the random state of the cupreous atom that eject gives and argon ion. In the meantime, we use 2 ° dispersive horn and 60 ° banking angle can inspect a gender to engrave corrode imitate to give IBE, implementation comes loose with inferior ionic hairdo the action that reflects reseau to quicken ion. Two imitate regard brilliant circle as rotate freely in process, it is the place of the confine that gets used to IBE and PVD, undertook adjustment to other technology measure. Graph 2 showed technology of fill of use Damascus copper (graph 2a) with PVD/IBE craft (graph 2b) establish the identical structure that give. To get used to the place of the certain confine of PVD/IBE, the final structure that requires for place founds same figure, we still joined extra craft step.
The experiment proves, although be put in these confine, still can make with PVD/IBE line piece equal 16nm SRAM (memory of static random access) circuit is unit. The metallic layer of above of all circuitry middle is made on plane, so its excel FinFET (transistor of effect of fin type field) parts of an apparatus interrelates complexly develop attacks structure, it is the scheme for selection of PVD/IBE metal thread. Graph the 3 independent structures that showed every metal layer, and the necessary step of structure of FinFET of metal of the use PVD/IBE three-layer that make.
Graph 3a and B showed the independent structure of every metal layer, and the necessary step that use PVD/IBE establishs structure of three-layer metal FinFET.
? Graph 3a: Zun Tu reveals shaping middle to make structure of Cheng 16nm FinFET, right graph shows the FinFET structure that has layer of 3 complete metals. The surface after the middle makes Cheng Zhi is even, cupreous PVD and IBE can undertake in this measure.
? Graph 3b: This graph showed the move that makes every metal layer with PVD/IBE, demonstrate to go out to fall to probe the process of craft and compositive method to create 3 metals layer in the circumstance of PVD and IBE existence confine. Every have match a graph to divide a pace accordingly analytic production flow, and involve partly columnar the structure is formed, cupreous PVD, chemical mechanical polish (CMP) , line and form removedly, oxide fill, IBE cuts deposit of corrode, atomic layer (the independent technology measure of graphic representation of etc of PVD of ALD) , copper.
Lie between the metallic line that open to form cent, need production interval and mesa act as insulation barrier layer. After grinding smooth deposit, can undertake line and removed graph are changed, and the aleatoric length on X or Y direction engraves corrode, make the line of corresponding direction thereby. When production via, can undertake across engraves corrode, the across of film of line attack by surprise that avoids X and Y direction is engraved corrode. The area that does not need via can cover insulation interval construction before metallic deposit.
03 resistor result and conclusion
Subsequently, we measured Damascus flow and PVD below two kinds of craft, most metal carrying a layer on the head is mixed to FinFET structure P the line resistor of via of N raceway groove. Graph the 4 start that reveal P and N passageway resistor to measure and terminus (other and all insulating material is transparent) . The osculatory resistor that changes tantalum liner layer and cupreous space to make up for nitrogen, we considered exterior scattering effect of the electron when computational copper resistor, from nitrogen the interface that change tantalum is jumped over close, cupreous resistor rate is higher, the attenuation length setting that resistor leads is 1nm. Predicting because of deposit of Damascus fill copper is not Quan Jing, so cupreous resistor leads promotion 50% . PVD/IBE copper craft does not use nitrogen to change tantalum liner layer, because this did not use exponential attenuation function, the body resistor that copper used in the model here is led. Graph the 4 resistor rate that include Damascus flow and PVD compare form.
Graph 4 showed the plan of model of 3D of FinFET parts of an apparatus that adopts Damascus flow and PVD technology, these model pictures give the resistance measurement point of P and N raceway groove. The form of 3D model lower part compared the Damascus of P and N raceway groove and PVD resistance. Form shows, the photograph is more deposit than Damascus, use IBE/PVD can reduce the resistance of 67% .
The resistance that from the model computation reachs makes clear, engrave corrode with traditional groove + methodological photograph compares Damascus deposit, use IBE/PVD to make a method can make resistor is reduced 67% . Because IBE/PVD does not need nitrogen to change tantalum liner layer,this is, and rate of resistor of the copper cash in this process is inferior. This result makes clear, in metallic thread production process, compare with Damascus fill photograph, IBE/PVD can lower resistor rate, but cost is workmanship more complex.
(Author: Software of branch of Semiverse Solutions of extensive forest group uses engineer Dr. Timothy Yang)
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