Method and apparatus for protecting tooling in a lead-free bath

Abstract

The disclosed embodiments represent a method and apparatus for improving a lead-free electroplating process in the manufacture of semiconductor devices. To prevent the buildup of undesirable copper or bismuth on a conveyor belt and the associated tooling used to transport integrated circuit devices through an electroplating bath, a metal more noble than copper or bismuth, depending on which is used as a plating metal, is plated onto the surface of the conveyor belt and associated tooling.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This present invention relates generally to the field of integrated circuit manufacture and, more specifically, to the field of plating metal on the external lead frames of integrated circuit packages.

[0003] 2. Description of the Related Art

[0004] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0005] Computer systems typically include a variety of electrically interconnected integrated circuit (I/C) packages which perform a variety of functions, including memory and processing functions. As integrated circuit devices have become more complex, so have the processes for manufacturing them. Integrated circuit manufacturers, such as the assignee of the present invention, invest heavily in state-of-the-art fabrication facilities (called “fabs”). Building complex integrated circuits involves processes that have many steps and sub-steps. Many of these processes employ chemical reactions that depend on the properties of the various types of metals used for different purposes in the integrated circuit manufacturing process. Different combinations of metals and chemicals are used in different processes because of their unique characteristics.

[0006] Electroplating is a process that may be used for many different purposes during the manufacturing of integrated circuits. In the process of electroplating, a metal or alloy of metals is deposited on a desired object to be plated. The object to be plated, which is frequently a different type of metal, is placed in a bath containing an electrolytic solution containing metal ions, leveling agents, and antioxidants. The object that is plated is sometimes referred to as a cathode. A quantity of the metal or metal alloy to be plated (or disposed) onto the object is also placed in the bath. In electroplating, the metal or metal alloy that is to be plated onto another object may be referred to as an anode. When an electric current is passed through the bath, an electric circuit that includes the plating metal (anode) and the object to be plated (cathode) is completed. The electric current causes metal ions that are present in the plating solution to be deposited on the object that is being plated. The metal ions from the electrolytic solution are replaced by the anode of the electric circuit, but the replacement of ions is not completely efficient.

[0007] One use of electroplating in the context of manufacturing integrated circuits is for depositing metal on the external electrical connections on the package of an integrated circuit. These external connections may take on any number of forms and are sometimes called “pins” or “leads.” The structure that holds the pins or leads together on the integrated circuit package is sometimes referred to as a “lead frame.” It is desirable to electroplate the lead frames of integrated circuit packages to provide a solderable surface so that the leads may be effectively soldered to a circuit board. Also, electroplating of the lead frame tends to prevent corrosion of the leads.

[0008] When integrated circuit devices are plated, each integrated circuit device is typically passed through an electroplating bath. The bath contains an electrolytic solution that may be optimized to transfer a particular metal to the target lead frames on the integrated circuit packages. To increase productivity, integrated circuit devices may be systematically and continuously passed through the electrolytic bath on a conveyor belt or the like. Each integrated circuit package may be secured to the conveyor belt with a metallic hook, clip, or other similar means. An electric current is passed through the electrolytic bath, and the pins of each integrated circuit package in turn are made a cathode in the electric circuit. A metal that is intended to be plated on the lead frame is disposed in the electrolytic bath and that metal forms an anode in the electric circuit that includes the lead frame and pins. As the integrated circuit package moves through the bath, its lead frame is plated with the plating material.

[0009] Pure tin (Sn) may be used as a plating material because of its excellent solderability characteristics. Tin is also very effective at preventing corrosion. However, the use of pure tin or nearly pure tin as a plating material results in a problem known as “whiskering.” Whiskering is an expression that refers to the development of tiny filaments of tin on the lead frame after being plated with pure or nearly pure tin. Tin whiskers are thought to be the result of recrystallization to relieve stress formed during plating. Whiskering is undesirable because the tiny tin filaments can contact and short out against other pins of the integrated circuit package or other areas of a circuit board on which the integrated circuit device is to be mounted. At this time, the phenomenon of whiskering is not fully understood and no industry testing standards are in place to define whether a coating is “whisker free.” To avoid tin whiskering, lead frames plated with pure tin or nearly pure tin may be subjected to hot dipping or reflowing above the melting point of tin. Alternatively, the addition of a minimum of 2% lead (Pb) to electroplated tin (Sn) has been determined to be very effective in reducing tin whiskering. Using a tin/lead (Sn/Pb) plating alloy to avoid whiskering may be more desirable than hot dipping or reflowing at elevated temperatures because improved process control is possible with tin/lead (Sn/Pb) plating. Accordingly, plating lead frames with a tin/lead (Sn/Pb) alloy instead of pure or nearly pure tin (Sn) has become a standard practice in the integrated circuit manufacturing industry.

[0010] One problem with typical plating processes is that lead (Pb) is becoming increasingly undesirable as a plating metal. Because of the undesirability of lead (Pb), its use in alloys with tin is also undesirable. Some alternatives to the use of Sn/Pb alloys have been discovered. Alloys of tin and copper (chemical symbol Cu), for example, are one such alternative. In symbol notation, these alloys are sometimes referred to as Sn/Cu alloys. Alloys of tin and bismuth (chemical symbol Bi) are also alternatives to the use of Sn/Pb alloys. Tin/bismuth alloys are sometimes referred to using the symbol Sn/Bi.

[0011] Unfortunately, the use of Sn/Cu and Sn/Bi alloys have some undesirable side effects. When Sn/Cu and Sn/Bi alloys are used as the cathode for electroplating, deposits of copper (in the case of Sn/Cu alloys) or bismuth (in the case of Sn/Bi alloys) tend to form on the surfaces of conveyor belts and clips or hooks used to secure integrated circuit packages to the conveyor belts. This happens through a process known as immersion plating, which occurs during periods of time when no electric current is being applied to the electrolytic plating solution in the associated electroplating bath. The resulting deposits of copper or bismuth significantly shorten the life of tooling such as conveyor belts and the associated the hooks or clips. The shortening of the life of the tooling results because the immersion plates are stripped off during the normal operation of the plating line. After stripping, the tooling is again subject to immersion plating when it is reused. Immersion plating is a galvanic replacement reaction that is self passivating. In other words, the belts and associated hooks and clips are essentially consumed because they are continually being stripped and subjected to subsequent immersion plating. A method and apparatus that reduces the effects of immersion plating on conveyor belts and associated tooling would be highly desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:

[0013] FIG. 1 is a perspective view of an electroplating machine;

[0014] FIG. 2 is a top view of an operational portion of an electroplating machine according to an embodiment of the present invention;

[0015] FIG. 3 is a cross-sectional view of the operational portion of the electroplating machine shown in FIG. 2 taken along line 2-2 of FIG. 2;

[0016] FIG. 4 is a detail view showing the connection of an integrated circuit device to the electroplating machine shown in FIG. 1 and FIG. 2;

[0017] FIG. 5 is a cross sectional view showing a surface of a conveyor belt or associated tooling that has been plated according to the present invention; and

[0018] FIG. 6 is a flow diagram illustrating an electroplating process according to the present invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0019] One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0020] Turning now to the drawings, FIG. 1 is a perspective view of an electroplating machine that may be used to electroplate the lead frames of integrated circuit devices. The electroplating machine is generally referred to by the reference numeral 1. As described below, the plating machine 1 may be adapted to deposit a plating metal on the lead frames of integrated circuit packages. The integrated circuit packages may be connected to a conveyor belt (see FIG. 2 and FIG. 3) and moved through the operational portions of the plating machine 1 for efficient processing.

[0021] FIG. 2 is a top view of an operational portion of an electroplating machine according to an embodiment of the present invention. The operational portion of the electroplating machine is represented generally by the reference numeral 10. A reservoir 12 contains an electrolytic solution 14. A sparger 13 having a U-shaped cross section (see FIG. 3) is disposed within the electrolytic bath 12. The sparger 13 is adapted to deliver the electrolytic solution 14 to the reservoir 12. One or more metal anodes 15 are disposed at various locations within the electrolytic bath 12. The metal from the metal anodes 15 is intended to be deposited on the lead frames of semiconductor packages during operation of the electroplating machine. The metal 15 may be comprised of pure or nearly pure tin (Sn) instead of an alloy of tin and copper (Cu) or bismuth (Bi). If pure or nearly pure tin is employed, copper (Cu) or bismuth (Bi) may be resupplied to the electrolytic solution 14 by adding concentrated solutions of Cu or Bi during operation of the plating machine 1 (FIG. 1).

[0022] A conveyor belt 16 is disposed to transport integrated circuit packages 18 through the electrolytic solution 14 contained in the electrolytic bath 12. The integrated circuit packages 18 are secured to the conveyor belt 16 by clips (see FIG. 3). A motor 24 is adapted to drive the conveyor belt 16 so that the integrated circuit packages 18 are passed through the electrolytic solution 14 in the electrolytic bath 12. The details of the construction of the motor 24 and the connection of the motor 24 to the conveyor belt 16 are matters of design choice and are not believed to be crucial aspects of the invention.

[0023] FIG. 3 is a cross-sectional view of the operational portion of the electroplating machine shown in FIG. 2 taken along line 2-2 of FIG. 2. Each integrated circuit device 18 is held to the conveyor belt 16 by a clip 20. Each of the metal anodes 15 is held in place by a hook 22a, 22b. The conveyor belt 16 is connected to the negative side of a power source and the metal anodes 15, via the hooks 22a, 22b, are connected to the positive side of a power source. As set forth above, the conveyor belt 16 and the clips 20 and hooks 22a, 22b have been susceptible to collecting deposits of copper or bismuth (depending on the composition of the metal anodes 15) through the process of immersion plating, which typically occurs when no electric current is passed through the electrolytic solution 14. Immersion plating typically occurs when the plating machine is not in normal operation.

[0024] The details of how the integrated circuit device 18 is secured to the conveyor belt 16 are shown in FIG. 4. The clip 20 secures the integrated circuit 18 to the conveyor belt 16 and provides an electrical connection between the integrated circuit 18 and the cathode. The integrated circuit 18 includes a lead frame 23 that is to be plated during normal operation of the plating machine 1 (FIG. 1).

[0025] As explained below, the accumulation of deposits on the conveyor belt 16 may be prevented by plating the conveyor belt 16 with a layer of metal that is more noble than the Cu or Bi. Similarly, the clips 20 and hooks 22a, 22b, as well as any other portion of the machine 1 that may be susceptible to undesirable copper or bismuth plating, may be protected by plating them with similar metal layers.

[0026] Deposits formed by immersion plating of the conveyor belt 16 and other tooling will be prevented or significantly reduced if the plated metal layers on each of those components are more noble than the deposited component of the metal anodes 15. For example, if the composition of the metal anodes 15 is tin (Sn) and the electrolytic solution 14 contains ions of copper (Cu) (or if the metal anodes are comprised of an alloy of tin and copper (Sn/Cu)), the deposited component will be copper. This means that, absent a plated layer that is more noble than copper, the conveyor belt 16 and other tooling is likely to accumulate deposits of copper by immersion plating. As another example, if the composition of the metal anodes 15 is tin (Sn) and the electrolytic solution 14 contains ions of bismuth (Bi) (or if the metal anodes are comprised of an alloy of tin and bismuth (Sn/Bi)), the deposited component will be bismuth. This means that, absent a plated layer that is more noble than bismuth, the conveyor belt 16 and other tooling is likely to accumulate deposits of bismuth by immersion plating.

[0027] Noble metals are generally characterized by a lack of chemical reactivity. In particular, noble metals do not react significantly to acids and are not susceptible to atmospheric corrosion. A metal is said to be “more noble” than a second metal if the “more noble” metal has a higher electrode potential than the second metal. Examples of metals that are more noble than copper or bismuth include, for example, silver, gold, palladium and platinum. The determination of whether a given metal is more noble than another metal can readily be performed by one of ordinary skill in the art.

[0028] In the disclosed embodiments, alloys of metals that are more noble than copper or bismuth (not just pure or nearly pure metals) may also be employed as plating materials. For example, gold alloys may be used as a plating material to avoid deposits on the conveyor belt 16 and associated hooks 22a, 22b or clips 20. Gold alloys are typically harder than pure gold and, thus, less susceptible to mechanical wear as the electroplating machine 1 operates In one known gold alloy, cobalt (Co) is alloyed with gold (Au) to form an alloy sometimes referred to as “hard Au.”

[0029] If the lead frame 23 of the integrated circuit component 18 being plated is not comprised of copper (Cu), then copper (Cu) may be plated onto the belts and associated tooling to reduce or prevent the effects of immersion plating. Similarly, copper (Cu) plating may be used as the plating material on the conveyor belt 16 and associated tooling when pure tin (Sn) or alloys of tin and copper (Sn/Cu) or alloys of tin and bismuth (Sn/Bi) are being plated onto the lead frames 23 of integrated circuit 18 except when the lead frame 23 itself is copper (Cu).

[0030] Examples of plating solutions that may be used to plate the conveyor belts 16, hooks 22a, 22b and/or clips 20 of a plating machine are Engelhard-Clal Supermex 230 Immersion Au solution or 100 ppm Pd/Cl dissolved in HCl. The former solution is used to plate gold (Au) onto the conveyor belt 16 and associated tooling. The latter solution is used to plate palladium (Pd) onto the conveyor belt 16 and associated tooling.

[0031] FIG. 5 is a cross sectional view of the surface of a metal component that has been plated according to the present invention. The metal 28 shown in FIG. 5 corresponds to the unplated surface of the conveyor belt 16, the clips 20, the hooks 22a, 22b or any other surface of the electroplating machine 1 (FIG. 1) that is plated according to the present invention. A noble metal layer 19 is depicted as being disposed on the surface 28. The noble metal layer 19 may be deposited on the surface 28 by any known method, including, for example, electroplating.

[0032] FIG. 6 is a flow diagram illustrating an exemplary embodiment of an electroplating process according to the present technique. The overall plating process is referred to generally by the reference numeral 30. Integrated circuit packages are typically pre-cleaned prior to electroplating. (block 32). The integrated circuit packages are also typically rinsed prior to being pre-dipped in plating acid (blocks 34 and 36). An additional rinsing operation may also be performed (block 37). The integrated circuit packages may undergo a plating bath using a plating machine such as the plating machine described above with reference to FIG. 1 (block 38). After processing in the plating bath, integrated circuit packages are typically cleaned and dried (blocks 40 and 42).

[0033] While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.

Claims

1. A plating machine clip for securing a device for processing in an electrolytic bath, comprising:

a plating machine clip having a metal more noble than copper plated thereon.

2. The plating machine clip of claim 1 wherein the metal comprises gold.

3. The plating machine clip of claim 1 wherein the metal comprises silver.

4. The plating machine clip of claim 1 wherein the metal comprises palladium.

5. The plating machine clip of claim 1 wherein the metal comprises platinum.

6. A plating machine clip for securing a device for processing in an electrolytic bath, comprising:

a plating machine clip having a metal more noble than bismuth plated thereon.

7. The plating machine clip of claim 6 wherein the metal comprises gold.

8. The plating machine clip of claim 6 wherein the metal comprises silver.

9. The plating machine clip of claim 6 wherein the metal comprises palladium.

10. The plating machine clip of claim 6 wherein the metal comprises platinum.

11. A plating machine hook for securing a device in an electrolytic bath, comprising:

a plating machine hook having a metal more noble than copper plated thereon.

12. The plating machine hook of claim 11 wherein the metal comprises gold.

13. The plating machine hook of claim 11 wherein the metal comprises silver.

14. The plating machine hook of claim 11 wherein the metal comprises palladium.

15. The plating machine hook of claim 11 wherein the metal comprises platinum.

16. A plating machine hook for securing a device in an electrolytic bath, comprising:

a plating machine hook having a metal more noble than bismuth plated thereon.

17. The plating machine hook of claim 16 wherein the metal comprises gold.

18. The plating machine hook of claim 16 wherein the metal comprises silver.

19. The plating machine hook of claim 16 wherein the metal comprises palladium.

20. The plating machine hook of claim 16 wherein the metal comprises platinum.

21. A plating machine conveyor belt for conveying a device through an electrolytic bath, comprising:

a plating machine conveyor belt having a metal more noble than copper plated thereon.

22. The plating machine conveyor belt of claim 21 wherein the metal comprises gold.

23. The plating machine conveyor belt of claim 21 wherein the metal comprises silver.

24. The plating machine conveyor belt of claim 21 wherein the metal comprises palladium.

25. The plating machine conveyor belt of claim 21 wherein the metal comprises platinum.

26. A plating machine conveyor belt for conveying a device through an electrolytic bath, comprising:

a plating machine conveyor having a metal more noble than bismuth plated thereon.

27. The plating machine conveyor belt of claim 26 wherein the metal comprises gold.

28. The plating machine conveyor belt of claim 26 wherein the metal comprises silver.

29. The plating machine conveyor belt of claim 26 wherein the metal comprises palladium.

30. The plating machine conveyor belt of claim 26 wherein the metal comprises platinum.

31. A plating machine for disposing a first metal comprising copper on a device, comprising:

an electrolytic bath containing an electrolytic solution comprising the first metal;

a conveyor belt adapted to transport the device through the electrolytic bath, the conveyor belt having a second metal more noble than copper plated thereon to prevent the first metal from depositing on the conveyor belt via immersion plating; and

a motor adapted to drive the conveyor belt.

32. The plating machine of claim 31 wherein the device is an integrated circuit device.

33. The plating machine of claim 31 wherein the second metal comprises gold.

34. The plating machine of claim 31 wherein the second metal comprises silver.

35. The plating machine of claim 31 wherein the second metal comprises palladium.

36. The plating machine of claim 31 wherein the second metal comprises platinum.

37. The plating machine of claim 31, comprising a clip adapted to secure the device to the conveyor belt, the clip having a third metal more noble than copper plated thereon.

38. The plating machine of claim 37, wherein the third metal comprises gold.

39. The plating machine of claim 37, wherein the third metal comprises silver.

40. The plating machine of claim 37, wherein the third metal comprises palladium.

41. The plating machine of claim 37, wherein the third metal comprises platinum.

42. A plating machine for disposing a first metal comprising bismuth on a device, comprising:

an electrolytic bath containing an electrolytic solution comprising the first metal;

a conveyor belt adapted to transport the device through the electrolytic bath, the conveyor belt having a second metal more noble than bismuth plated thereon to prevent the first metal from depositing on the conveyor belt via immersion plating; and

a motor adapted to drive the conveyor belt.

43. The plating machine of claim 42 wherein the device is an integrated circuit device.

44. The plating machine of claim 42 wherein the second metal comprises gold.

45. The plating machine of claim 42 wherein the second metal comprises silver.

46. The plating machine of claim 42 wherein the second metal comprises palladium.

47. The plating machine of claim 42 wherein the second metal comprises platinum.

48. The plating machine of claim 42, comprising a clip adapted to secure the device to the conveyor belt, the clip having a third metal more noble than bismuth plated thereon.

49. The plating machine of claim 48, wherein the third metal comprises gold.

50. The plating machine of claim 48, wherein the third metal comprises silver.

51. The plating machine of claim 48, wherein the third metal comprises palladium.

52. The plating machine of claim 48, wherein the third metal comprises platinum.

53. A method of electroplating at least a portion of an integrated circuit package, the method comprising the acts of:

securing the integrated circuit device to a device that is plated with a metal more noble than copper; and

electroplating the at least a portion of the integrated circuit device in a plating bath;

54. The method of claim 53, further comprising the act of pre-cleaning the at least a portion of the integrated circuit device.

55. The method of claim 53, further comprising the act of rinsing the at least a portion of the integrated circuit device.

56. The method of claim 53, further comprising the act of pre-dipping the at least a portion of the integrated circuit device in plating acid.

57. The method of claim 53, further comprising the act of cleaning the at least a portion of the integrated circuit device.

58. The method of claim 53, further comprising the act of drying the at least a portion of the integrated circuit device.

59. The method of claim 53, further comprising the act of disposing a metal comprising an Sn/Cu alloy in the plating bath.

60. The method of claim 53, further comprising the act of transporting the integrated circuit device through the plating bath.

61. A method of electroplating at least a portion of an integrated circuit device, the method comprising the acts of:

securing the integrated circuit device to a device that is plated with a metal more noble than bismuth; and

electroplating the at least a portion of the integrated circuit device in a plating bath.

62. The method of claim 61, further comprising the act of pre-cleaning the at least a portion of the integrated circuit device.

63. The method of claim 61, further comprising the act of rinsing the at least a portion of the integrated circuit device.

64. The method of claim 61, further comprising the act of pre-dipping the at least a portion of the integrated circuit device in plating acid.

65. The method of claim 61, further comprising the act of cleaning the at least a portion of the integrated circuit device.

66. The method of claim 61, further comprising the act of drying the at least a portion of the integrated circuit device.

67. The method of claim 61, further comprising the act of disposing a metal comprising an Sn/Bi alloy in the plating bath.

68. The method of claim 61, further comprising the act of transporting the integrated circuit device through the plating bath.

69. A plating machine, comprising:

a reservoir adapted to contain an electrolytic solution comprising copper;

a conveyor adapted to transport a device through the reservoir, the conveyor having a metal more noble than copper disposed there on; and

a motor adapted to drive the conveyor.

70. The plating machine of claim 69 wherein the metal comprises gold.

71. The plating machine of claim 69 wherein the metal comprises silver.

72. The plating machine claim 69 wherein the metal comprises palladium.

73. The plating machine of claim 69 wherein the metal comprises platinum.

74. The plating machine of claim 69, comprising a clip adapted to secure the device to the conveyor, the clip having a second metal more noble than copper plated thereon.

75. The plating machine of claim 74, wherein the second metal comprises gold.

76. The plating machine of claim 74, wherein the second metal comprises silver.

77. The plating machine of claim 74, wherein the second metal comprises palladium.

78. The plating machine of claim 74, wherein the second metal comprises platinum.

79. A plating machine, comprising:

a reservoir adapted to contain an electrolytic solution comprising bismuth;

a conveyor adapted to transport a device through the reservoir, the conveyor having a metal more noble than bismuth disposed there on; and

a motor adapted to drive the conveyor.

80. The plating machine of claim 79 wherein the metal comprises gold.

81. The plating machine of claim 79 wherein the metal comprises silver.

82. The plating machine claim 79 wherein the metal comprises palladium.

83. The plating machine of claim 79 wherein the metal comprises platinum.

84. The plating machine of claim 79, comprising a clip adapted to secure the device to the conveyor, the clip having a second metal more noble than bismuth plated thereon.

85. The plating machine of claim 84, wherein the second metal comprises gold.

86. The plating machine of claim 84, wherein the second metal comprises silver.

87. The plating machine of claim 84, wherein the second metal comprises palladium.

88. The plating machine of claim 84, wherein the second metal comprises platinum.

89. A method of using a plating machine, the plating machine having a conveyor, the method comprising the acts of:

securing a device to be plated to the conveyor, the conveyor having a metal plated thereon, the metal being more noble than copper;

moving the conveyor to immerse the device in an electrolytic bath; and

plating a second metal onto at least a portion of the device to be plated.

90. The method set forth in claim 89, further comprising the act of plating the metal more noble than copper onto the conveyor.

91. The method set forth in claim 89 wherein the metal more noble than copper comprises gold.

92. The method set forth in claim 89 wherein the metal more noble than copper comprises silver.

93. The method set forth in claim 89 wherein the metal more noble than copper comprises palladium.

94. The method set forth in claim 89 wherein the metal more noble than copper comprises platinum.

95. A method of using a plating machine, the plating machine having a conveyor, the method comprising the acts of:

securing a device to be plated to the conveyor, the conveyor having a metal plated thereon, the metal being more noble than bismuth;

moving the conveyor to immerse the device in an electrolytic bath; and

plating a second metal onto at least a portion of the device to be plated.

96. The method set forth in claim 95, further comprising the act of plating the metal more noble than bismuth onto the conveyor.

97. The method set forth in claim 95 wherein the metal more noble than bismuth comprises gold.

98. The method set forth in claim 95 wherein the metal more noble than bismuth comprises silver.

99. The method set forth in claim 95 wherein the metal more noble than bismuth comprises palladium.

100. The method set forth in claim 95 wherein the metal more noble than bismuth comprises platinum.

101. A method of plating a conveyor belt for use in a plating machine, the method comprising the acts of:

providing a conveyor belt; and

plating a metal more noble than copper onto the conveyor belt so that the conveyor belt is adapted for use in the plating machine without accumulating deposits of a plating metal thereon.

102. The method of claim 101 wherein the metal more noble than copper comprises gold.

103. The method of claim 101 wherein the metal more noble than copper comprises silver.

104. The method of claim 102 wherein the act of plating comprises employing a plating solution comprising Engelhard-Clal Supermex 230 Immersion Au solution.

105. The method of claim 101 wherein the metal more noble than copper comprises palladium.

106. The method of claim 105 wherein the act of plating comprises employing a plating solution comprising Pd/Cl dissolved in HCl.

107. The method of claim 101 wherein the metal more noble than copper comprises platinum.

108. A method of plating a conveyor belt for use in a plating machine, the method comprising the acts of:

providing a conveyor belt; and

plating a metal more noble than bismuth onto the conveyor belt so that the conveyor belt is adapted for use in the plating machine without accumulating deposits of a plating metal thereon.

109. The method of claim 108 wherein the metal more noble than bismuth comprises gold.

110. The method of claim 108 wherein the metal more noble than bismuth comprises silver.

111. The method of claim 109 wherein the act of plating comprises employing a plating solution comprising Engelhard-Clal Supermex 230 Immersion Au solution.

112. The method of claim 108 wherein the metal more noble than bismuth comprises palladium.

113. The method of claim 112 wherein the act of plating comprises employing a plating solution comprising Paladium Chloride HCL.

114. The method of claim 108 wherein the metal more noble than bismuth comprises platinum.