Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/40—Formation of materials, e.g. in the shape of layers or pillars of conductive or resistive materials
  • H10P14/46—Formation of materials, e.g. in the shape of layers or pillars of conductive or resistive materials using a liquid
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/40—Formation of materials, e.g. in the shape of layers or pillars of conductive or resistive materials
  • H10P14/46—Formation of materials, e.g. in the shape of layers or pillars of conductive or resistive materials using a liquid
  • H10P14/47—Electrolytic deposition, i.e. electroplating; Electroless plating

Definitions

• the present invention relates generally to semiconductor manufacturing technology and more specifically to electroplating systems using consumable anodes.
• Copper is not suited for deposition using the metallization techniques used for aluminum and is better adapted for deposition by electro- or electro-less plating processes out of a solution.
• the adoption of the copper interconnect the device connection technology, there has been a great deal of effort placed into automating copper plating technology for semiconductors. This has meant the introduction of expensive equipment. This in turn has meant that much effort has been expended in trying to reduce costs.
• One of the processes for depositing copper uses a consumable primary anode in the plating chamber.
• Non-uniform deposition of the copper leads to difficulties in following planarization steps and in defective integrated circuits around the perimeter of the semiconductor wafer.
• the present invention provides an electroplating system for semiconductor wafers including a plating chamber having a consumable remote secondary anode connected by a circulating system to a plating solution reservoir.
• the semiconductor wafer is used as the cathode with an inert primary anode in the plating chamber and a remote consumable secondary anode in the plating solution reservoir for providing the metal ions for plating.
• the consumption of the consumable shielded secondary anode does not change the geometry or the electromotive force in the plating chamber and maintains a uniform thickness conductor core deposition which is easily planarized.
• the present invention further provides a copper electroplating system for semiconductor wafers including a plating chamber having a consumable copper remote secondary anode connected by a recirculating system to a copper plating solution reservoir.
• the semiconductor wafer is used as the cathode with an inert platinum anode in the plating chamber and a remote consumable copper secondary anode in the plating solution reservoir for providing the metal ions for plating.
• the consumption of the consumable copper shielded secondary anode does not change the geometry or the electromotive force in the plating chamber and maintains a uniform thickness conductor core deposition which is easily planarized.
• FIG. 1 shows a plating chamber containing a consumable anode
• FIG. 2 shows a plating chamber with a portion of the consumable anode consumed
• FIG. 3 shows a plating chamber having the remote anode of the present invention.
• FIG. 1 PRIOR ART
• an electroplating system 10 having a plating chamber 12.
• the plating chamber 12 has an outlet 14 connected to a recirculating pump 16 which is further connected to an inlet 18 to the plating chamber 12.
• a consumable primary anode 20 connected to a positive voltage source 22.
• a semiconductor wafer 24 having a conductive seed layer
• the seed layer 26 is connected by a connector 28 to a negative voltage source 30 and acts as the cathode for the plating process.
• the semiconductor wafer 24 is positioned so as to place the seed layer 26 in contact with a plating solution 32.
• the consumable primary anode 20 is made of copper and the plating solution 32 contains free copper ions.
• the plating solution 32 is recirculated by the recirculating pump 16 to maintain as constant a copper ion concentration as possible while the cathodic reaction at the seed layer 26 causes the deposition of metallic copper on to the seed layer 26.
• FIG. 2 PRIOR ART
• the consumable primary anode 20 is shown partially consumed and significantly reduced in size which changes the geometry and the electromotive force in the plating chamber 12.
• the shape of the electromotive field influences the deposition of the metal ions on the seed layer 26 of the semiconductor wafer 24.
• the deposition of a metal 27 on the semiconductor wafer 24 will be uneven and generally concave.
• the metal 27 will be thickest where the distance between the consumable primary anode 20 and the semiconductor wafer 24 is the shortest and will be thinner where the consumable primary anode 20 and the semiconductor wafer 24 are further apart.
• the variation in thickness of the metal 27 makes it very difficult to properly planarize the semiconductor wafer 24 by subsequent chemical-mechanical planarization processes and results in defective integrated circuits around the perimeter of the semiconductor wafer 24.
• the electroplating system 50 includes a plating chamber 52 having an outlet 54 connected to a recirculating pump 56 which is further connected by an inlet 58 to a plating solution reservoir 60.
• the plating solution reservoir 60 is connected by a second inlet 61 to the plating chamber 52.
• Witfiin the plating chamber 52 is an inert primary anode 64 connected to a positive voltage source 62.
• the inert primary anode 64 is a semiconductor wafer 66 having a conductive seed layer 68 thereon.
• the seed layer 68 is connected by a connector 69 to a negative voltage source 70 and acts as the cathode for the plating process.
• the semiconductor wafer 66 is positioned so as to place the seed layer 68 in contact with a plating solution 72.
• a consumable remote secondary anode 75 In the plating solution reservoir 60 is a consumable remote secondary anode 75.
• the consumable remote secondary anode 75 is connected to tlie positive voltage source 62 and is in fluid communication with the inert primary anode 64 via the second inlet 61.
• the consumable remote secondary anode 75 is placed so that, as it is consumed, the geometry and the electromotive field in the plating chamber 52 do not change so the electromotive field for metal ions plated on the seed layer 68 is always the same and directly between tlie inert primary anode 64 and the semiconductor wafer 66 as indicated by the straight arrows 76.
• the plated metal 78 on the seed layer 68 will be of a uniform thickness which will be easily planarized by subsequent chemical-mechanical planarization processes.
• the consumable remote secondary anode 75 introduces metal ions to the plating solution 72 in the plating solution reservoir 60.
• the plating solution 72 is then recirculated to the plating chamber 52 either by gravity feed (as shown) or pumping (not shown).
• the inert primary anode 70 and the seed layer 68 provide the electromotive force to deposit the metal ions onto the seed layer 68.
• the pump 56 as shown
• gravity fed not shown
• the seed layer 68 is of copper deposited by a process such as sputtering or chemical vapor deposition, and the inert primary anode 64 is of platinum (Pt), and the consumable remote secondary anode 75 is of metallic copper.

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• Electroplating Methods And Accessories (AREA)
• Electrodes Of Semiconductors (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (2)

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• 2000
  • 2000-10-02 US US09/678,503 patent/US6413390B1/en not_active Expired - Fee Related
• 2001
  • 2001-06-04 AU AU2001275274A patent/AU2001275274A1/en not_active Abandoned
  • 2001-06-04 JP JP2002533357A patent/JP2004510888A/ja active Pending
  • 2001-06-04 CN CNB018167659A patent/CN1333442C/zh not_active Expired - Fee Related
  • 2001-06-04 DE DE60140305T patent/DE60140305D1/de not_active Expired - Lifetime
  • 2001-06-04 KR KR1020037004726A patent/KR100747132B1/ko not_active Expired - Fee Related
  • 2001-06-04 WO PCT/US2001/018229 patent/WO2002029875A2/en not_active Ceased
  • 2001-06-04 EP EP01941966A patent/EP1323186B1/en not_active Expired - Lifetime
  • 2001-10-02 TW TW090124242A patent/TW525245B/zh not_active IP Right Cessation

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