[go: up one dir, main page]

WO1997015070A2 - Fabrication method and contact bump structure for high-density surface-mount connections of solid-state device chips - Google Patents

Fabrication method and contact bump structure for high-density surface-mount connections of solid-state device chips Download PDF

Info

Publication number
WO1997015070A2
WO1997015070A2 PCT/FI1996/000536 FI9600536W WO9715070A2 WO 1997015070 A2 WO1997015070 A2 WO 1997015070A2 FI 9600536 W FI9600536 W FI 9600536W WO 9715070 A2 WO9715070 A2 WO 9715070A2
Authority
WO
WIPO (PCT)
Prior art keywords
contact
passivation layer
bumps
layer
onto
Prior art date
Application number
PCT/FI1996/000536
Other languages
French (fr)
Other versions
WO1997015070A3 (en
Inventor
Ahti Aintila
Original Assignee
Picopak Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Picopak Oy filed Critical Picopak Oy
Publication of WO1997015070A2 publication Critical patent/WO1997015070A2/en
Publication of WO1997015070A3 publication Critical patent/WO1997015070A3/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/10—Bump connectors ; Manufacturing methods related thereto
    • H01L24/12—Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the groups H01L21/18 - H01L21/326 or H10D48/04 - H10D48/07
    • H01L21/4814—Conductive parts
    • H01L21/4846—Leads on or in insulating or insulated substrates, e.g. metallisation
    • H01L21/4853—Connection or disconnection of other leads to or from a metallisation, e.g. pins, wires, bumps
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
    • H01L23/488—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of soldered or bonded constructions
    • H01L23/498—Leads, i.e. metallisations or lead-frames on insulating substrates, e.g. chip carriers
    • H01L23/49811—Additional leads joined to the metallisation on the insulating substrate, e.g. pins, bumps, wires, flat leads
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/10—Bump connectors ; Manufacturing methods related thereto
    • H01L24/11—Manufacturing methods
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02—Bonding areas; Manufacturing methods related thereto
    • H01L2224/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/05—Structure, shape, material or disposition of the bonding areas prior to the connecting process of an individual bonding area
    • H01L2224/0554—External layer
    • H01L2224/05599—Material
    • H01L2224/056—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
    • H01L2224/05617—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof the principal constituent melting at a temperature of greater than or equal to 400°C and less than 950°C
    • H01L2224/05624—Aluminium [Al] as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/12—Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H01L2224/13—Structure, shape, material or disposition of the bump connectors prior to the connecting process of an individual bump connector
    • H01L2224/13001—Core members of the bump connector
    • H01L2224/13099—Material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01006—Carbon [C]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01013—Aluminum [Al]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01019—Potassium [K]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01029—Copper [Cu]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/0103—Zinc [Zn]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01033—Arsenic [As]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01046—Palladium [Pd]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01073—Tantalum [Ta]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01078—Platinum [Pt]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01079—Gold [Au]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01082—Lead [Pb]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/013—Alloys
    • H01L2924/0132—Binary Alloys
    • H01L2924/01322—Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/013—Alloys
    • H01L2924/014—Solder alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/30—Technical effects
    • H01L2924/301—Electrical effects
    • H01L2924/3025—Electromagnetic shielding

Definitions

  • the invention relates to a fabrication method according to the preamble of claim 1 for forming contact bumps for high-density surface-mounting of solid-state device chips.
  • the invention also concerns a contact bump structure for high-density surface-mounting of solid-state device chips.
  • a plurality of methods have been developed for direct bonding of diced, unpac aged solid-state device chips onto bonding substrates of electronic circuitry.
  • One of such methods is the rapidly in the art adopted flip-chip method.
  • this method onto the contact pad area (bonding pad area) , typically having aluminium pads, of the solid-state device chip are formed contact bumps of a height projecting substantially (typically 25-50 ⁇ m) above their surrounding structures, after which the bumps are connected to the contact pads of the conductor pattern on the bonding substrate of said electronic cir- cuit by carrying out " the connections using mechanical compression bonding, solder bonding, isotropic or aniso ⁇ tropic adhesive bonding with an electrically conductive adhesive, electroless chemical or electrolytic deposition bonding, or by combinations of these processes.
  • the most commonly used process is solder bonding.
  • Both the solder and adhesive bonding methods involve a risk of short circuit to the adjacent contact bump if the facing sides of the bumps are so close to each other that the conductive particles of the adhesive can at a high probability form a conductive bridge between the bump sides, or respectively, if solder is administered due to inaccurate metering in excessive amounts filling the space between the adjacent bump sides or if the surface tension of the solder can pull an excessively thick layer of solder to the sides of the bumps as compared to the width of the interbump gap. Due to such difficulties, some manufacturers recommend 200 ⁇ m as the minimum bump raster and a minimum gap of 100 ⁇ m as the interbump space.
  • the formation of the contact bumps involves prob ⁇ lems.
  • the bumps are typically made by an electroless chemical or electrolytic wet process in strongly alkaline or acid electrolyte solutions that have a tendency of etching the structures of the solid-state device chips, particularly in cases that the protecting barrier, known as the passivation layer, of device has manufacturing defects or is comprised of materials of weak chemical resistance.
  • the most common ones of these defects occur chiefly at the edges of the aluminium metallization layer as thin spots of the passivation layer that are caused by the anisotropic character of deposition methods used, namely, that the preferential growth of passivation layers occurs in their thickness direction. Resultingly, the steps of the underlying layers remain weakly protected.
  • the goal of the invention is achieved by depositing an oxide passivation layer on both the passivation layer of the silicon wafer and the edge sides of contact bumps using the ALE (Atomic Layer Epitaxy) process. More specifically, the method according to the invention is characterized by what is stated in the characterizing part of claim 1.
  • contact bump structure according to the invention is characterized by what is stated in the characterizing part of claim 3.
  • the invention offers significant benefits.
  • the edge sides of the contact bump By coating the edge sides of the contact bump with an oxide layer deposited using the ALE process, whereby the deposited oxide leaves only the bump top free for accept ⁇ ing the dispensed solder and participating in the bonding process, the melting solder is prevented from wetting the interbump gaps, thus eliminating the risk of short cir- cuits by solder bridging even at medium-density contact spacing.
  • a chemically deposited solder layer of approx. 15 ⁇ m thickness grown on the top of the bump as the sole solder application process.
  • the oxide layer deposited on the edge and side areas of the bump provides an effective barrier to the formation of solder bridging even at narrow interbump gaps.
  • anisotropically conducting adhesives even a greater number of conducting particles landing in the interbump space will not cause a risk of short circuit, because the ALE layers discussed in the examples below provide a mechanically strong layer of high dielectric strength.
  • Minimized encapsulation also has the benefit of improving heat transfer to the ambient structures, which by virtue of the lowered operating temperature extends the service life of the device, which typically is doubled for each 10 K drop of the device internal temperature.
  • Figure 1 is a longitudinally sectioned side view of a bump structure according to the invention.
  • Figure 2 is a longitudinally sectioned side view of a detail of a bump structure made using conventional techniques.
  • Figure 3 is a detail of the structure shown in Fig. 1.
  • bumps 4 such as those shown in Fig. 1 is commenced in a conventional manner starting from a semiconductor wafer 1 having a passivation layer 3 opened at the aluminium metallization contact pad areas 2, after which the bare metallic contact pads are catalytically activated in a zincate bath or a palladium-tin salt solu ⁇ tion in order to improve the growth of the nickel layer and its adherence to the underlying structures.
  • the base of the bump 4 is grown in an electroless chemical nickel bath so that the height increase of the nickel bump follows an almost isotropic growth geometry extend ⁇ ing also laterally sideways over the passivation layer 3 reaching in accordance with typical industrial standards at least 7 ⁇ m over the edge of the passivation layer opening.
  • the compositions of conventional processes do not usually cause uncontrolled etch-away defects in the semiconductor structures.
  • the strongly alkaline solutions used herein may remove a portion of the silicon dioxide and silicon nitride passivation layer 3, underetching the material of layer from under the edge 7 of the nickel bump 4 as shown in Fig. 2, finally ex- tending even up to the aluminium layer 2 and causing etch-away of this layer, too.
  • the gold layers 6 are thin and the process times short in conventional pro ⁇ Des, the above-mentioned 7 ⁇ m overextension of the nickel layer has been considered to provide a sufficient protection against such etch-away of the aluminium layer.
  • the present invention offers a possibility of protecting aluminium metallizations and other structures of a semiconductor wafer against undesirable etch-away during longer-lasting and more aggressive process steps, as well as under actual in-circuit operating conditions of the fabricated solid-state device in a hostile environment.
  • the semiconductor wafer with the ready-made nickel bumps is coated using the ALE (Atomic Layer
  • Epitaxy process, based on superimposing atomic layers by means of alternated surface reaction cycles.
  • the process is described in greater detail in, e.g. , US patent documents including US. Pat. Nos. 4,058,430, 4,413,022 and 4,389,973.
  • the semiconductor wafer is coated using cited process with a thin (e.g., 100-200 nm thick) oxide passivation layer 5, whose isotropic growth mechanism is characteristic of the process and capable of providing defect-free deposition on stepped structures.
  • the layer 5 may be formed by an aluminium oxide or tantalum oxide layer that have been found to give good protection to the semiconductor wafer 1 during subsequent process steps. In the ALE process, both types of this layer 5 grow typical ⁇ ly at a process temperature of approx.
  • openings in the layers 5 are made, using photolithography and etching techniques, to the center of the bumps 4 so that an insulating and protecting layer remains on the top and sides of the bumps 4. Subsequently, openings to a tantalum oxide layer may be etched by means of, e.g., fluorine plasma, while openings in an aluminium oxide layer are conventionally made using orthophosphoric acid.
  • a semiconductor wafer thus protected can be taken to desired further processing for the purpose of plating the unprotected metallic nickel bumps in an electroless pro ⁇ cess with, e.g., gold, which as such is metal of excel ⁇ lent compatibility with solder.
  • metal of excel ⁇ lent compatibility with solder e.g., gold
  • One alternative metal offering improved solderability over that of nickel is chemically deposited copper.
  • Another interesting struc- ture can be achieved by chemically depositing an almost eutectic tin-lead solder layer over copper.
  • the essential property of the pre- sent invention is that the protective layer 5 deposited by means of the ALE process gives an efficient barrier in a plurality of chemical deposition processes shielding the processed structures against the risk of etch-away.
  • the above-described ALE layer may be used as a process barrier for a plurality of different bump struc ⁇ tures already during the first metallization steps, whereby any possible pores, cracks and pinholes in the actual passivation layer are conformantly covered.
  • the ALE layer may also be used as an new passivation layer for locating contact bumps in new places with the help of an additional metallization layer.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Ceramic Engineering (AREA)
  • Internal Circuitry In Semiconductor Integrated Circuit Devices (AREA)
  • Wire Bonding (AREA)

Abstract

The invention relates to a method of forming contact bumps (4) onto metallic contact pad areas (2) on the surface of a substrate (1) and a contact bump structure made using the method. According to the invention, using an ALE process, onto the substrate (1) is formed an oxide passivation layer (5) which in the subsequent process step is opened at required points (4).

Description

Fabrication method and contact bump structure for high- density surface-mount connections of solid-state device chips
The invention relates to a fabrication method according to the preamble of claim 1 for forming contact bumps for high-density surface-mounting of solid-state device chips.
The invention also concerns a contact bump structure for high-density surface-mounting of solid-state device chips.
A plurality of methods have been developed for direct bonding of diced, unpac aged solid-state device chips onto bonding substrates of electronic circuitry. One of such methods is the rapidly in the art adopted flip-chip method. In this method, onto the contact pad area (bonding pad area) , typically having aluminium pads, of the solid-state device chip are formed contact bumps of a height projecting substantially (typically 25-50 μm) above their surrounding structures, after which the bumps are connected to the contact pads of the conductor pattern on the bonding substrate of said electronic cir- cuit by carrying out "the connections using mechanical compression bonding, solder bonding, isotropic or aniso¬ tropic adhesive bonding with an electrically conductive adhesive, electroless chemical or electrolytic deposition bonding, or by combinations of these processes. The most commonly used process is solder bonding.
Both the solder and adhesive bonding methods involve a risk of short circuit to the adjacent contact bump if the facing sides of the bumps are so close to each other that the conductive particles of the adhesive can at a high probability form a conductive bridge between the bump sides, or respectively, if solder is administered due to inaccurate metering in excessive amounts filling the space between the adjacent bump sides or if the surface tension of the solder can pull an excessively thick layer of solder to the sides of the bumps as compared to the width of the interbump gap. Due to such difficulties, some manufacturers recommend 200 μm as the minimum bump raster and a minimum gap of 100 μm as the interbump space.
Also the formation of the contact bumps involves prob¬ lems. The bumps are typically made by an electroless chemical or electrolytic wet process in strongly alkaline or acid electrolyte solutions that have a tendency of etching the structures of the solid-state device chips, particularly in cases that the protecting barrier, known as the passivation layer, of device has manufacturing defects or is comprised of materials of weak chemical resistance. The most common ones of these defects occur chiefly at the edges of the aluminium metallization layer as thin spots of the passivation layer that are caused by the anisotropic character of deposition methods used, namely, that the preferential growth of passivation layers occurs in their thickness direction. Resultingly, the steps of the underlying layers remain weakly protected.
It is an object of the present invention to overcome the drawbacks of the above-described techniques and to achieve an entirely novel type of contact bump structure and fabrication method of such structures for high- density surface-mounting of solid-state device chips.
The goal of the invention is achieved by depositing an oxide passivation layer on both the passivation layer of the silicon wafer and the edge sides of contact bumps using the ALE (Atomic Layer Epitaxy) process. More specifically, the method according to the invention is characterized by what is stated in the characterizing part of claim 1.
Furthermore, the contact bump structure according to the invention is characterized by what is stated in the characterizing part of claim 3.
The invention offers significant benefits.
By coating the edge sides of the contact bump with an oxide layer deposited using the ALE process, whereby the deposited oxide leaves only the bump top free for accept¬ ing the dispensed solder and participating in the bonding process, the melting solder is prevented from wetting the interbump gaps, thus eliminating the risk of short cir- cuits by solder bridging even at medium-density contact spacing. For extra-high-density contact structures, it is preferable to use a chemically deposited solder layer of approx. 15 μm thickness grown on the top of the bump as the sole solder application process. Also in this case, the oxide layer deposited on the edge and side areas of the bump provides an effective barrier to the formation of solder bridging even at narrow interbump gaps. When using anisotropically conducting adhesives, even a greater number of conducting particles landing in the interbump space will not cause a risk of short circuit, because the ALE layers discussed in the examples below provide a mechanically strong layer of high dielectric strength.
Also under actual operating conditions of high humidity and corrosive ambient, corrosive substances are prevented from attacking the device structures that are entirely protected by films grown using the ALE process, which contributes to significant reliability improvement of solid-state devices and their service life even when the conventional plastic package of the device is omitted or reduced to a minimum due to mechanical space constraints. Minimized encapsulation also has the benefit of improving heat transfer to the ambient structures, which by virtue of the lowered operating temperature extends the service life of the device, which typically is doubled for each 10 K drop of the device internal temperature.
In the following, the invention will be examined in more detail by means of exemplifying embodiments with reference to the attached drawings, in which:
Figure 1 is a longitudinally sectioned side view of a bump structure according to the invention;
Figure 2 is a longitudinally sectioned side view of a detail of a bump structure made using conventional techniques; and
Figure 3 is a detail of the structure shown in Fig. 1.
As the structure and method disclosed herein can be applied to a plurality of bump formation processes and connection techniques, only one exemplifying embodiment of the invention is discussed adapted to a nickel bump deposited using conventional chemical techniques.
The deposition of bumps 4 such as those shown in Fig. 1 is commenced in a conventional manner starting from a semiconductor wafer 1 having a passivation layer 3 opened at the aluminium metallization contact pad areas 2, after which the bare metallic contact pads are catalytically activated in a zincate bath or a palladium-tin salt solu¬ tion in order to improve the growth of the nickel layer and its adherence to the underlying structures. Next, the base of the bump 4 is grown in an electroless chemical nickel bath so that the height increase of the nickel bump follows an almost isotropic growth geometry extend¬ ing also laterally sideways over the passivation layer 3 reaching in accordance with typical industrial standards at least 7 μm over the edge of the passivation layer opening. During these process steps, the compositions of conventional processes do not usually cause uncontrolled etch-away defects in the semiconductor structures. How¬ ever, if the deposition of the nickel layer 4 is subse¬ quently continued by deposition of another layer 6 such as a gold layer, it is often noticed that the strongly alkaline solutions used herein may remove a portion of the silicon dioxide and silicon nitride passivation layer 3, underetching the material of layer from under the edge 7 of the nickel bump 4 as shown in Fig. 2, finally ex- tending even up to the aluminium layer 2 and causing etch-away of this layer, too. As the gold layers 6 are thin and the process times short in conventional pro¬ cesses, the above-mentioned 7 μm overextension of the nickel layer has been considered to provide a sufficient protection against such etch-away of the aluminium layer.
For advanced bonding metallurgical processes, the present invention offers a possibility of protecting aluminium metallizations and other structures of a semiconductor wafer against undesirable etch-away during longer-lasting and more aggressive process steps, as well as under actual in-circuit operating conditions of the fabricated solid-state device in a hostile environment. For this purpose, the semiconductor wafer with the ready-made nickel bumps is coated using the ALE (Atomic Layer
Epitaxy) process, based on superimposing atomic layers by means of alternated surface reaction cycles. The process is described in greater detail in, e.g. , US patent documents including US. Pat. Nos. 4,058,430, 4,413,022 and 4,389,973. The semiconductor wafer is coated using cited process with a thin (e.g., 100-200 nm thick) oxide passivation layer 5, whose isotropic growth mechanism is characteristic of the process and capable of providing defect-free deposition on stepped structures. The layer 5 may be formed by an aluminium oxide or tantalum oxide layer that have been found to give good protection to the semiconductor wafer 1 during subsequent process steps. In the ALE process, both types of this layer 5 grow typical¬ ly at a process temperature of approx. 300 °C, which is sufficiently low not to cause damage even to the most sensitive memory devices. The openings in the layers 5 are made, using photolithography and etching techniques, to the center of the bumps 4 so that an insulating and protecting layer remains on the top and sides of the bumps 4. Subsequently, openings to a tantalum oxide layer may be etched by means of, e.g., fluorine plasma, while openings in an aluminium oxide layer are conventionally made using orthophosphoric acid.
A semiconductor wafer thus protected can be taken to desired further processing for the purpose of plating the unprotected metallic nickel bumps in an electroless pro¬ cess with, e.g., gold, which as such is metal of excel¬ lent compatibility with solder. One alternative metal offering improved solderability over that of nickel is chemically deposited copper. Another interesting struc- ture can be achieved by chemically depositing an almost eutectic tin-lead solder layer over copper. Besides the exemplifying processes mentioned above, a great number of further alternative deposition processes are given in the literature of the art. The essential property of the pre- sent invention is that the protective layer 5 deposited by means of the ALE process gives an efficient barrier in a plurality of chemical deposition processes shielding the processed structures against the risk of etch-away.
Obviously, the above-described ALE layer may be used as a process barrier for a plurality of different bump struc¬ tures already during the first metallization steps, whereby any possible pores, cracks and pinholes in the actual passivation layer are conformantly covered. The ALE layer may also be used as an new passivation layer for locating contact bumps in new places with the help of an additional metallization layer.

Claims

Claims:
1. A method of forming contact bumps (4) onto metallic contact pad areas (2) on the surface of a substrate (1) , c h a r a c t e r i z e d in that
- using an ALE process, onto the substrate (1) is formed an oxide passivation layer (5) which in the subsequent process step is opened at required points (4) .
2. A method as defined in claim 1 for forming contact bumps (4) onto metallic contact pad areas (2) on the surface of a substrate (1) , in which method
- onto said substrate (1) and partially on said contact pad areas (2) is formed a passivation layer (3) , and
- said contact bumps (4) are formed onto said contact pads (2) ,
c h a r a c t e r i z e d in that
- using an ALE process, onto said contact bumps
(4) is formed an oxide passivation layer (5) which in the subsequent process step is opened at said contact bumps (4) .
2. A contact bump structure for high-density surface- mounting of components, said structure comprising
- a substrate (1) ,
- contact pad areas (2) formed on said substrate
(1), - a passivation layer (3) covering said sub¬ strate (1) and at least partially said contact pad areas, and
- contact bumps (4) formed onto said contact pad areas (2) ,
c h a r a c t e r i z e d in that
- said passivation layer (3) and the edge sur¬ faces of said contact bumps (4) are covered with an oxide passivation layer (5) formed using an ALE process.
PCT/FI1996/000536 1995-10-16 1996-10-10 Fabrication method and contact bump structure for high-density surface-mount connections of solid-state device chips WO1997015070A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI954922A FI954922L (en) 1995-10-16 1995-10-16 Manufacturing method and contact bump structure for dense surface connections of semiconductor chips
FI954922 1995-10-16

Publications (2)

Publication Number Publication Date
WO1997015070A2 true WO1997015070A2 (en) 1997-04-24
WO1997015070A3 WO1997015070A3 (en) 1997-06-12

Family

ID=8544199

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1996/000536 WO1997015070A2 (en) 1995-10-16 1996-10-10 Fabrication method and contact bump structure for high-density surface-mount connections of solid-state device chips

Country Status (2)

Country Link
FI (1) FI954922L (en)
WO (1) WO1997015070A2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004105149A1 (en) 2003-05-16 2004-12-02 E.I. Dupont De Nemours And Company Barrier films for plastic substrates fabricated by atomic layer deposition
US6969589B2 (en) 2001-03-30 2005-11-29 Perlegen Sciences, Inc. Methods for genomic analysis

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE393967B (en) * 1974-11-29 1977-05-31 Sateko Oy PROCEDURE AND PERFORMANCE OF LAYING BETWEEN THE STORAGE IN A LABOR PACKAGE
FI57975C (en) * 1979-02-28 1980-11-10 Lohja Ab Oy OVER ANCHORING VIDEO UPDATE FOR AVAILABILITY
US4389973A (en) * 1980-03-18 1983-06-28 Oy Lohja Ab Apparatus for performing growth of compound thin films
US5455459A (en) * 1992-03-27 1995-10-03 Martin Marietta Corporation Reconstructable interconnect structure for electronic circuits
FI946015A7 (en) * 1994-07-08 1996-01-09 Picopak Oy Electroless contact nodule formation method

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6969589B2 (en) 2001-03-30 2005-11-29 Perlegen Sciences, Inc. Methods for genomic analysis
US11031098B2 (en) 2001-03-30 2021-06-08 Genetic Technologies Limited Computer systems and methods for genomic analysis
WO2004105149A1 (en) 2003-05-16 2004-12-02 E.I. Dupont De Nemours And Company Barrier films for plastic substrates fabricated by atomic layer deposition
US8445937B2 (en) 2003-05-16 2013-05-21 E I Du Pont De Nemours And Company Barrier films for plastic substrates fabricated by atomic layer deposition

Also Published As

Publication number Publication date
WO1997015070A3 (en) 1997-06-12
FI954922A0 (en) 1995-10-16
FI954922A7 (en) 1997-04-17
FI954922L (en) 1997-04-17

Similar Documents

Publication Publication Date Title
JP3398609B2 (en) Semiconductor device
KR100454381B1 (en) Semiconductor device and manufacturing method thereof
EP0261799B1 (en) Method for producing a terminal electrode of a semi-conductor device
KR100290193B1 (en) Semiconductor device, and method of manufacturing the same
USRE46466E1 (en) Method for fabricating low resistance, low inductance interconnections in high current semiconductor devices
US7855103B2 (en) Wirebond structure and method to connect to a microelectronic die
US6593222B2 (en) Method to improve the reliability of thermosonic gold to aluminum wire bonds
EP0382080A2 (en) Bump structure for reflow bonding of IC devices
JP3949505B2 (en) CONNECTION TERMINAL, ITS MANUFACTURING METHOD, SEMICONDUCTOR DEVICE, AND ITS MANUFACTURING METHOD
JPH0689919A (en) Electric internal connection substrate provided with both wire bond and solder connection and manufacture
KR20050087840A (en) Structure and method for bonding to copper interconnect structures
JP5064632B2 (en) Method and apparatus for forming an interconnect structure
JP2002190550A (en) Method for manufacturing semiconductor device
KR20060131647A (en) Semiconductor device and manufacturing method thereof
JP2001060760A (en) Circuit electrode and method for forming the same
US20010013651A1 (en) Semiconductor device and manufacturing method therefor
WO1997015070A2 (en) Fabrication method and contact bump structure for high-density surface-mount connections of solid-state device chips
JPS6112047A (en) Manufacture of semiconductor device
JP2006120803A (en) Semiconductor device and manufacturing method of semiconductor device
KR100237671B1 (en) Semiconductor device manufacturing method
JPH05335315A (en) Electrode manufacturing method
KR100597994B1 (en) Solder bump of semiconductor package and manufacturing method thereof
JPH02138740A (en) Manufacture of semiconductor device
JPH0677274A (en) Semiconductor device bonding wire
JPH03132036A (en) Manufacturing method of semiconductor device

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A2

Designated state(s): DE JP US

AL Designated countries for regional patents

Kind code of ref document: A2

Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE

AK Designated states

Kind code of ref document: A3

Designated state(s): DE JP US

AL Designated countries for regional patents

Kind code of ref document: A3

Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase