Brilliant round class is enclosed is the craft before pointing to brilliant circular cut. Brilliant round class encloses cent to be entered for fan model chip of brilliant round class is enclosed (Fan-In WLCSP) go out with fan model chip of brilliant round class is enclosed (Fan-Out WLCSP) , its characteristic is to be in whole in enclosing a process, brilliant circle keeps complete from beginning to end. Besides, reapportion layer (RDL) enclose, rewind (Flip Chip) enclose the via that reach silicon 1 (TSV) enclose also be enclosed for brilliant round class by classify normally, although these enclose a method,completed partial process only before brilliant circular cut. Different the metal that encloses methodological place to use and eletroplate (Electroplating) 2 scale design also all not identical. Nevertheless, in enclosing a process, these a few kinds of methods follow following order basically.

1 silicon via (TSV, through-Silicon Via) : One kind can cross silicon completely naked piece or the perpendicular each other that brilliant circle realizes silicon chip pile connects.

2 eletroplate (Electroplating) : Round class of a brilliant encloses craft, through oxidation happening on positive pole response produces an electron, guide the electron in the electrolyte solution that serves as cathode, the metallic ion that makes this solution medium is in brilliant round face by reductive into the metal.

After circle of the brilliant that finish checks, insulation layer is made on brilliant circle according to demand (Dielectric Layer) . The first time after exposure, insulation layer is opposite again through photoetching technology chip solder dish have exposure. Next, shoot through splashing (Sputtering) 3 craft besmear in brilliant round face Fu metal layer. The report that this metal layer can enhance to be formed in follow-up measure is aureate the adhere force that belongs to a layer, still can serve as at the same time diffuse barrier layer produces chemical reaction with preventing metallic interior. In addition, metallic layer still can be in eletroplate electronic passageway acts as in the process. Tu Fuguang engraves glue later (Photoresist) in order to form electric film, adopt design of photoetching craft scale, recycle eletroplates form a thick metallic layer. Eletroplate after finishing, undertake photoetching glue goes glue craft, use layer of thin metal of the rest of purify of quarter corrode craft. Finally, plating metal layer is in report brilliant round face is made finished place to require design. These design can act as fan is entered model layer of the down-lead of WLCSP, reapportion encloses medium solder dish redistribution, and rewind encloses medium protruding dot. Later development will have detailed introduction to every working procedure.

3 splash shoot (Sputtering) : One uses plasma bundle undertake to target material physics is touched attack, make material particle falls off and deposit is in target the craft on brilliant circle.

Graph 2: Photoetching technology measure

In brilliant circle class is enclosed in, photoetching craft basically is used at pattern is being made in the draw on insulation layer, use scale design to found electric film then, form metallic line through engraving corrode diffusion layer.

Graph 3: The contrast of photography and photoetching

To understand photoetching technology clearly more, might as well have its and photography technology comparative. If the graph is shown 3 times, photography aether sunshine is caught as illuminant film object, the object can be mark of object, ground or character. And the design move that photoetching needs specific illuminant to get on model of attack by surprise arrives on exposure facility. Additional, the film in camera also but the photoetching glue that analogy is Fu of the besmear in photoetching craft to go up in brilliant circle. If the graph is shown 4 times, we can pass 3 kinds of methods to besmear photoetching glue Fu is on brilliant circle, include besmear coming back (Spin Coating) , filmy lamination (Film Lamination) with spray (Spray Coating) . After Tu Fuguang engraves glue, need to use before passing, carbonado (Soft Baking) come purify dissolvent, go up in order to ensure agglutinant photoetching glue is withheld in brilliant circle and maintain its originally ply.

If the graph is shown 5 times, besmear coming back besmears agglutinant photoetching glue Fu is in rotating brilliant round center, centrifugal force can make photoetching glue diffuses to brilliant curl predestined relationship, go up in brilliant circle dispersedly with even ply thereby. Viscosity is taller rotate speed is lower, photoetching mucus is thicker. Conversely, viscosity is lower rotate speed is higher, photoetching glue is thinner. Round to brilliant class is enclosed and character, especially rewind is enclosed, the ply of photoetching sub must achieve M of 30 μ to come M of 100 μ , ability is formed solder protruding dot. However, besmear through Chan Cixuan very inaccessible place needs ply. Below certain circumstance, before Tu Guang coming back engraves glue and undertaking for many times repeatedly, need carbonadoes. Accordingly, the circumstance with photoetching thicker sub needs to fall in place, use lamination method is more effective, because this kind of method can make from initiative phase photoetching glue film achieves place to need ply, won’t cause brilliant circle to waste in handling a process at the same time, cost effectiveness is accordingly taller also. But, if brilliant is round structural surface is rough, adhere to photoetching glue film very hard in brilliant round face, this kind of circumstance issues use lamination method, can cause product defect. So, be aimed at the brilliant circle with very rough surface, can adopt spray method, make photoetching glue ply keeps even.

Graph 5: Sketch map of method of besmear coming back

After before glue of the photoetching that finish besmears Fu is mixed, carbonadoing, have exposure with respect to need next. Pass illuminate, the design that gets on model of attack by surprise projects on the photoetching glue of brilliant round face. As a result of sexual photoetching glue (Positive PR) in bate of the meeting after exposure, because this is used when sexual photoetching glue, need to be in starting a hole of area of purify of model of attack by surprise. Glue of negative sex photoetching (Negative PR) meet after exposure sclerotic, need to withhold area starting a hole in model of attack by surprise so. Circle class encloses brilliant to use model of attack by surprise to aim exposure opportunity normally (Mask Aligner) 4 or the pace takes type photoetching chance (Stepper) 5 as photoetching technological equipment.

Model of 4 attack by surprise aims exposure opportunity (Mask Aligner) : A kind of design that gets on model of attack by surprise and brilliant circle undertake aiming, make the light crosses model of attack by surprise and illuminate is in the exposure facility of brilliant round face.

5 paces take type photoetching chance (Stepper) : One kind is when work station is progressively and mobile, mix through open shut shutter to control the light in order to have the machine of photoetching.

Develop (Development) be use developer solution one kind to dissolve the craft of the photoetching glue of because of photoetching craft bate. If the graph is shown 6 times, develop method can be divided it is 3 kinds, include: Puddle type develop (Puddle Development) , enter developer solution brilliant round center, hand-in-hand travel low speed rotates; Immersion type develop (Tank Development) , many brilliant circle immerge developer solution is medium at the same time; Gush drenchs type develop (Spray Development) , spray developer solution on brilliant circle. Graph the 7 working principles that demonstrated static develop method. After develop of the static state that finish, make through photoetching technology photoetching glue forms requires circuit design.

Splash shooting is the deposit of physical gas phase that in brilliant circle the surface forms metallic film one kind (PVD) 6 craft. If brilliant is round,go up formation metallic film encloses medium protruding dot under rewind, be called layer of the metal below protruding dot (UBM, under Bump Metallurgy) . Normally protruding nods next metallic layers to be comprised by film of metal of layer or two three-layer, include: Enhance the adhere layer of sex of brilliant round agglutinate; Can be in eletroplate those who offer an electron is carry to carry in the process shed a layer; And have solder wetability (Wettability) 7, can prevent what compound forms between film and metal to diffuse barrier layer. For example film is comprised by titanium, copper and nickel, criterion titanium layer regards adhere as the layer, cupreous layer serves as carry shed a layer, nickel layer serves as barrier layer. Accordingly, UBM is very important to ensuring the quality that rewind encloses reachs dependability. Wait in RDL and WLCSP in enclosing craft, the action of metallic layer basically is to form metallic lead, accordingly normally by can raise agglutinant adhere layer to reach carry shed a layer to form.

Deposit of 6 physics gas phase (PVD) : One kind produces metallic steam, regard a kind of ply as its thinner and the technology that has agglutinant pure metal or alloy coating deposit to go up in conductor.

7 wetability (Wettability) : Because of the interaction of liquid and solid surface, the phenomenon that makes the liquid diffuses in solid surface.

If the graph is shown 8 times, splashing in shooting craft, enrage argon translate into plasma above all (Plasma) 8, use ion next bundle meet the capable person that hit target (Target) , the composition of target material and deposit the metallic class status of argon ion is same. Touch after attacking, the metallic grain on target material can fall off and deposit is in brilliant round face. Shoot through splashing, deposit metallic grain is had those who agree is directional. Although brilliant circle is even the ply after the area passes deposit is even, but groove or perpendicular each other connect road (via) deposit ply may be put in difference, because of this with respect to deposit ply character, this kind of irregular appearance can bring about parallel the deposit ply of the substrate surface at metallic deposit direction, than perpendicular the ply of substrate surface deposit at metallic deposit direction is thin.

8 plasma (Plasma) : A kind of freedom because of proton and electron moves and assume electrically neutral material position. When undertaking heating making its warm up to aeriform form substance continuously, can produce the particle aggregate that comprises by ion and free electron. Plasma also is regarded as solid state, liquid state and gaseous state besides ” status of the 4th kind of material ” .

Eletroplating is electrolyte solution medium metallic ion is reductive be a metal and deposit is in the process of brilliant round face, this process is to need to pass exterior offerred electron undertakes reductive response will come true. In brilliant circle class is enclosed in, use eletroplate craft forms thick metal layer. Thick metal layer can act as realize down-lead of electric connective metal, or the protruding dot that is weld. If the graph is shown 9 times, the metal on positive pole can be become by oxidation ionic, circuit of outward ministry releases an electron. The in reaching consist in solution metal ion that is oxidized in zincous place can receive an electron, the metal is made after passing reductive reaction. Eletroplate in what brilliant round class encloses in craft, cathode is brilliant circle. Positive pole is made by the metal that regards report as film, but also can use the gold that be like platinum not dissolve sex electrode (Insoluble Electrode) 9. If in relief plate is made by the metal that serves as film, metallic ion is met dissolve from in relief plate and diffuse continuously, in order to maintain consistency of pH indicator of the ion in solution. If use not dissolve sex electrode, the metal that brilliant round face must arrive because of deposit in fixed and compensatory solution and uses up is ionic, in order to maintain metallic ion chroma. Graph the 10 electrochemistry that revealed cathode and positive pole to happen respectively react.

9 not dissolve sex electrode (Insoluble Electrode) : One kind basically is used at the electrode that electroanalysis and eletroplates. Dissolve of its both neither at chemical solution, also not dissolve at electrochemistry solution. The material such as platinic gold often is used at making not dissolve sex electrode.

Graph 10: Cathode and zincous electrochemistry reaction are formulary