Metal fusion bonding – Process – Plural diverse bonding
Reexamination Certificate
2001-01-12
2003-07-22
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
Plural diverse bonding
C228S179100, C228S180220, C228S180210, C228S245000
Reexamination Certificate
active
06595404
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method of producing an electronic part with bumps, such as a mounting substrate, a semiconductor package, a semiconductor wafer, a semiconductor chip and etc., in which a plurality of conductive bumps for electrical connection are formed, and relates to another method of producing an electronic part in which method a first electronic part with bumps is bonded to a second electronic part such as a substrate.
In recent years, for realizing the high density design of electronic circuit and the high speed design of signal transmission in the electronic circuit, there is adopted a connection system using bumps for connecting a printed board to a semiconductor package.
As regards conventional technique is known JP-A-9-199506 (Conventional Technique 1). Namely, in Conventional Technique 1 there is disclosed a method comprising the steps of: forming nickel film on each of electrode pads provided on a wafer, selectively forming a adhesive film on each of the electrode pads, then excessively supplying solder particles so that some of the solder particles are adhered to the nickel film through the adhesive film, shaking excessive solder particles off the adhesive film by use of brush etc., supplying flux onto each of the solder particles adhered to the adhesive film, and heating and melding the solder particles so that solder bumps may be formed.
As another conventional technique is also known JP-A-6-152120 (Conventional Technique 2). In Conventional Technique 2, solder powder is spread on adhesive film previously formed, and then the reflow thereof is performed so that a thin solder layer such as priming solder may be formed.
However, in the method of Conventional Technique 1, in a case where the size of each of electrode pads is smaller than that of the solder particle, the electrode pad is apt to be located among a plurality of adjacent solder particles with the result that the necessary solder particles do not come to be adhered onto the pads, so that there is such a fear as the failure of bonding is apt to occur. On the other hand, in another case where the size of each of the pad electrodes is equal to or is somewhat larger than that of the solder particle, a plurality of solder particles are apt to be adhered onto the electrode pad, which causes such an unfavorable state as some of resultant solder bumps come to have volume two or three times as large as that of each of normal bumps although each of the resultant bumps must have the same volume each other, so that connection reliability required when a substrate or a board is mounted is deteriorated. Further, the removing of excess solder particles by use of, for example, a brush is apt to remove such solder particles temporarily adhered as to be formed into solder bumps, so that there occurs such a fear as failure in connection is caused.
On the other hand, in the method of Conventional Technique 2, solder powder of particles each sufficiently smaller in size than the size of each of the pads are spread onto each of the pads, and then the reflow of the solder powder is performed, so that the resultant bumps are prevented from having sizes quite different from each other, however, the adhering amount of the solder powder is limited to be not more than the volume of a value multiplying a pad surface area by the height of the solder powder. Thus, in order to obtain solder bumps each having a sufficient volume, the several repetitions of the step are required unfavorably, which is not practical.
SUMMARY OF THE INVENTION
The first object of the invention is to obtain a method of producing an electronic part with bumps which can solve the above problems, in which method one solder ball having a volume corresponding to an intended solder bump volume is surely supplied onto an adhesive portion, whereby even solder bumps each having a large volume can be formed by a single step while preventing the solder bumps from having various volumes different from each other, and the second object of the invention is to obtain another method of producing electronic parts in which method the electronic part with bumps is bonded to another electronic part such as a substrate or board.
In the invention, in order to achieve the object of the invention, adhesive film is selectively formed on electrode pads of a semiconductor device or on electrode pads each formed by metallizing with, for example, Ni on metal conductor of the semiconductor device, a solder preform having a predetermined volume being then supplied onto the adhesive film formed on each of the pads through a stencil mask or an adsorption mask so that the solder preform may be adhered to the adhesive film regarding each of the pads, and the reflow of the solder preforms is performed, after coating the preforms with flux as occasion demands, so that a solder bump having a predetermined volume may be formed on each of the electrode pads.
Namely, according to the first aspect of the invention, there is provided a method of producing an electronic part with bumps, comprising: selectively forming an adhesive film on each of a plurality of pad portions provided on the electronic component; aligning and supplying a bonding member onto each of the adhesive films; and bonding each of the bonding members to each of the pad portions by melting the bonding member so that each of the bumps is formed on each of the pad portions.
According to the second aspect of the invention, there is provided a method of producing on electronic part with bumps, comprising the steps of:
selectively forming adhesive film on each of a plurality of pad portions provided on said electronic component, which forming is performed by immersing the electronic component in a fluid containing imidazole derivative which is adsorbed on metallic portions and which is not adsorbed on portions other than the metallic portions;
aligning and supplying a bonding member onto said adhesive film formed on each of said pad portions; and
bonding each of said bonding members to each of said pad portions by melting said bonding member so that each of said bumps is formed of said bonding member and so that each of said bumps is bonded to each of said pad portions.
A method of producing an electronic part with bumps according to the first aspect of the invention, wherein the thickness of the adhesive film is made to be not less than 5 &mgr;m in the adhesive film-forming step.
According to the third aspect of the invention, there is provided a method of producing an electronic part with bumps, comprising the steps of:
selectively forming adhesive film on each of a plurality of pad portions provided on said electronic component, which forming is performed by immersing the electronic component in a fluid containing imidazole derivative which is adsorbed on metallic portions and which is not adsorbed on portions other than the metallic portions;
aligning and supplying a bonding member onto said adhesive film formed on each of said pad portions, which aligning and supplying are performed by use of both of an aligning mask having opening portions capable of aligning and supplying said bonding members and an aligning squeegee capable of moving the bonding members into said opening portions; and
bonding each of said bonding members, which are supplied in the bonding member-aligning-and-supplying step, to each of said pad portions by melting said bonding member so that each of said bumps is formed of said bonding member and so that each of said bumps is bonded to each of said pad portions.
According to the fourth aspect of the invention, there is provided a method of producing electronic circuit, comprising the steps of:
selectively forming adhesive film on each of a plurality of pad portions provided on a first electronic part;
aligning and supplying a bonding member to said adhesive film formed on each of said pad portions in said adhesive film-forming step;
relatively aligning each of said pad portions of the first electronic part, each of which pad portions is provided with said bonding member supp
Inoue Kosuke
Oroku Noriyuki
Suzuki Takamichi
Yamaguchi Yoshihide
Antonelli Terry Stout & Kraus LLP
Dunn Tom
Edmondson L.
Hitachi , Ltd.
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