Evaporation/sputtering, thin metal films

The deposition of thin metallic films carried out by electrochemical or other methods, such as classical evaporation or sputtering of a solid metal source, may all benefit... 

For thin-film metallization, a thin metallic film is first deposited onto the surface of the substrate. The deposition can be accomplished by thermal evaporation, electronic-beam- or plasma-assisted sputtering, or ion-beam coating techniques, all standard microelectronic processes. A silicon wafer is the most commonly used substrate for thin-film sensor fabrication. Other substrate materials such as glass, quartz, and alumina can also be used. The adhesion of the thin metallic film to the substrate can be enhanced by using a selected metallic film. For example, the formation of gold film on silicon can be enhanced by first depositing a thin layer of chromium onto the substrate. This procedure is also a common practice in microelectronic processing. However, as noted above, this thin chromium layer may unintentionally participate in the electrode reaction. 

A SPR spectrometer has the following four principal components a source of radiation, an optical coupling element, a thin metallic film and a detector. Thin layers of SPR active metals are most often produced by vacuum evaporation or sputtering. 

In thin-film metallization by evaporation or sputtering of thin metal films onto a ceramic surface (Chapter 28), it has been demonstrated that a sequence of layers of different metals is required for optimum film properties. The first layer is usually a refractory metal such as Ti, Cr, or NiCr this layer provides adhesion to the ceramic. These elements are reactive and bond through redox reactions with the substrate. The second layer acts as a diffusion barrier. The barrier material will usually be a noble metal, preferably Pt or Pd. The top layer will be the metal of choice for the particular application, for example, Au for wire-bonding applications and Ni or Ag-Pd for solderability. 

The most reliable and easy to control method of oxide films application is provided by either sputtering of an oxide layer (e. g., by a laser beiun), or evaporation of a thin metal zinc film (its resistance is usually 5-10 Ohm) from tantalum vessel onto a thoroughly prepared clean quartz substrate in a vacuum of Torr (containing no oil and... 

Carbide or nitride films were also made by reacting metal films deposited by thermal evaporation or d.c. sputtering on MgO or Si02 with a flow of reactive gas at high temperature. The reactive gas was a CH4/H2 mixture or pure NH3. The reaction time was typically 2-4 h. As it is known that many phases of the metals can exist (bcc Cr, fee Cr, bee Mo, fee Mo, bcc W, fee W,. . . ), we will only present in this chapter the results where the precursor is the normal phase (the bcc metal). The conditions to prepare thin films of metals in this form have been described earlier.10... 

Chemical vapor deposition is a key process in microelectronics fabrication for the deposition of thin films of metals, semiconductors, and insulators on solid substrates. As the name indicates, chemically reacting gases are used to synthesize the thin solid films. The use of gases distinguishes chemical vapor deposition (CVD) from physical deposition processes such as sputtering and evaporation and imparts versatility to the deposition technique. 

Thin films of thickness typically 10 nm are readily formed in a vacuum chamber by evaporation, sputtering , or chemical vapour deposition (CVD). Many metals and metal alloys, e.g. aluminium, silver, gold and Ni-Cr, can be... 

Metal thin films deposited on polymers are widely used in various industrial domains such as microelectronics (capacitors), magnetic recording, packaging, etc. Despite much attention that has been paid in the recent literature on the adhesive properties of metals films on polyimide (PI)( 1 - 5 ) and polyethyleneterephtalate (PET)((L) it appears that a better knowledge of the metal/polymer interface is needed. In this paper we focus ourself on the relationship between the adhesion and the structural properties of the aluminum films evaporated (or sputtered) on commercial bi-axially stretched PET (Du Pont de Nemours (Luxembourg) S.A.). A variety of treatment (corona, fluorine,etc.) have been applied in order to improve the adhesion of the metallic layer to the polymer. The crystallographic... 

For the formation of a metallic film in addition to thick film silk-screen technique, thin film metallization is another means for the film deposition. Deposition of thin film can be accomplished by either physical or chemical means, and thin film technology has been extensively used in the microelectronics industry. Physical means is basically a vapor deposition, and there are various methods to carry out physical vapor deposition. In general, the process involves the following 1) the planned deposited metal is physically converted into vapor phase and 2) the metallic vapor is transported at reduced pressure and condensed onto the surface of the substrate. Physical vapor deposition includes thermal evaporation, electronic beam assisted evaporation, ion-beam and plasma sputtering method, and others. The physical depositions follow the steps described above. In essence, the metal is converted into molecules in the vapor phase and then condensed onto the substrate. Consequently, the deposition is based on molecules and is uniform and very smooth. 

Thermocompression bonding is a process in which soft metals such as Au are squeezed into each other with high force at elevated temperature. Thin films of metals can be deposited on the surface of wafers by evaporation, sputtering, or plating. 

Audiere et al. (122) described a thin-film micro-DTA apparatus that permitted the study in situ of thin-film materials. The samples are deposited by evaporation, cathodic sputtering, and so on, on to a substrate bearing metallic films, which constitute the thermocouples of the DTA. The sample... 

---