JPS6325919A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form an electrode onto a semiconductor substrate in extremely uniform film thickness, and to obtain a semiconductor device having excellent mechanical characteristics and electrical characteristics by concentrically arranging an auxiliary electrode to the semiconductor substrate as a cathode in an electrolytic plating tank and applying fixed voltage between anodes. CONSTITUTION:A ring-shaped auxiliary cathode 15 is dipped in a plane including a semiconductor substrate 11 in arrangement concentric to the semiconductor substrate 11 in an electrolyte 13. The auxiliary cathode 15 is formed by silicon having the same quality as the semiconductor substrate 11 and resistivity of 15-20OMEGA-cm, thickness (t) is set to 1mm, an inside diameter D1 to 66mm and an outside diameter to 76mm, and the cathode 15 is dipped, shaping a clearance of approximately 2mm between the cathode 15 and the semiconductor substrate 11. Fixed voltage is applied among the semiconductor substarte 11 and the auxiliary cathode 15 and anodes 14 by power supplies 16a, 16b. 1-4A currents are conducted among the anodes 14 and the semiconductor substrate 11 for approximately two min., and Ni in thickness of 0.5mum is precipitated on the surfaces of the semiconductor substrate 11 through electrolytic plating, thus shaping electrode plating films. The semiconductor substrate 11 is taken but of an electrolytic plating tank 12, and the electrode plating films are patterned through a photoetching method and an electrode is formed, thus acquiring a semiconductor device.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a method for manufacturing a semiconductor device.

[Prior Art] Conventionally, in a semiconductor device, an electrode plating film is formed on the surface of a semiconductor substrate 1 using, for example, an electrolytic plating bath as shown in FIG. 4, and this electrode plating film is patterned to form a predetermined electrode. It is manufactured by A semiconductor substrate J is immersed in a liquid 3 in an electrolytic plating bath 2 as a cathode. An anode 4 is immersed in the electrolytic solution 3 so as to face the surface of the semiconductor substrate 1 .

Thus, the semiconductor substrate 1 is connected to the power source 6 via the clip 5.
A predetermined voltage is applied between the anode 4 and the anode 4, and metal is deposited on the surface of the semiconductor substrate 1 by electrolytic plating to form an electrode plating film. Next, a semiconductor device is obtained by patterning the electrode plating film to form predetermined electrodes.

[Problems to be Solved by the Invention] However, in the semiconductor device obtained as described above, the current density is large in the peripheral region of the semiconductor substrate 1, and the thickness of the electrode plating film is smaller than that in other regions. becomes significantly larger. Electrodes made from such electrode plating films are
Naturally, the thickness is non-uniform. Moreover, since the expansion coefficients of the electrode formed in this way and the semiconductor substrate 1 are different,
The electrodes are likely to peel off or defects may occur in the semiconductor substrate 1. As a result, there was a problem in that the mechanical properties and electrical properties of the semiconductor device could not be sufficiently improved.

[Means for Solving the Problems] The present invention involves immersing a semiconductor substrate as a cathode in a predetermined electrolytic solution, immersing an anode so as to face the surface of the semiconductor substrate, and including the semiconductor substrate. An auxiliary cathode is immersed in a plane concentrically with the semiconductor substrate, and a predetermined voltage is applied between the anode, the auxiliary cathode, and the semiconductor substrate to form an electrode plating film on the surface of the semiconductor substrate. A method of manufacturing a semiconductor device is characterized in that:

[Function] According to the method for manufacturing a semiconductor device according to the present invention, 1! An auxiliary cathode is arranged concentrically with the semiconductor substrate serving as a cathode in the plating bath, and a predetermined voltage is applied between the anodes to form an electrode plating film on the surface of the semiconductor substrate.

Since this electrode plating film is turned into a predetermined electrode, the obtained electrode has an extremely uniform film thickness. As a result, a semiconductor device with excellent mechanical and electrical properties can be easily obtained.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing the structure of an electrolytic plating bath used in the method of the present invention. In this example, the present invention is applied to the manufacture of a semiconductor device comprising a rectifying element. In the figure, 11 is a semiconductor substrate immersed as a cathode in an electrolytic solution 13 in an electrolytic plating bath 12. Semiconductor substrate 1
1 is formed of an N-type silicon substrate having a diameter of 2.5 inches, a specific resistance of 15 to 20 Ω, and a thickness of 250 μm. A junction is formed within the semiconductor substrate 11 at a predetermined depth.

The electrolytic solution 13 includes 10 parts by weight of nickel ammonium sulfate,
1 part by weight of boric acid, 1 part by weight of ammonium chloride, 88 parts by weight of pure water
It consists of an aqueous solution mixed in parts by weight. t
Inside the wI solution 1, Ni is placed opposite the surface of the semiconductor substrate 11.
An anode 14 made of a plate is immersed. In addition, electrolyte 1
3 includes a ring-shaped auxiliary cathode 15 as shown in FIG.
However, the semiconductor substrates 11 are immersed in a concentric arrangement within a plane including the semiconductor substrates 11. The auxiliary cathode J5 is made of silicon having a specific resistance of 15 to 20 Ω-α, which is the same as that of the semiconductor substrate 11, and has a wall thickness t of 1 mm, an inner diameter DI of 66 mm, an outer diameter D2 of 76 mm, and a semiconductor substrate 11. I) about 2
It is immersed with gaps between the fins. A predetermined voltage is applied between the semiconductor substrate J1 and the auxiliary cathode 15 and anode 14 by power supplies 16m and 16b.

Then, a current of 1 to 4 A is passed between the anode 14 and the semiconductor substrate 11 for about 2 minutes, and N1 with a thickness of 0.5 μm is deposited on the surface of the semiconductor substrate 11 by electrolytic plating to form an X-electrode plating film. Formed. Next, the semiconductor substrate 1 on which the electrode plating film was formed was taken out from the electrolytic plating bath 12, and the electrode plating film was patterned by a well-known photolithography method to form electrodes, thereby obtaining a semiconductor device.

In this case, the thickness of the electrode plating film was extremely uniform over the metal surface of the semiconductor substrate 11, as shown by the characteristic line (2) in FIG. It has been experimentally confirmed that if the thickness of the electrodes of the obtained semiconductor device is uniform, the semiconductor device will have excellent mechanical and electrical properties.

Incidentally, the film thickness of the electrode plating film formed by the conventional method shown in FIG. 4 is significantly thicker in the area around the semiconductor substrate 10, as shown in FIG. 3 by the characteristic line (■). It turns out that there is.

Note that the auxiliary cathode 15 may be formed of metal such as copper or copper, and its shape is preferably set appropriately depending on the properties of the semiconductor substrate 11 and the like.

[Effects of the Invention] As explained above, according to the method for manufacturing a semiconductor device according to the present invention, a t-pole is formed on a semiconductor substrate with an extremely uniform film thickness, thereby producing a semiconductor with excellent mechanical and electrical properties. The device can be easily obtained.

[Brief Description of the Drawings] Fig. 1 is an explanatory diagram showing the configuration of an electrolytic plating bath used in the method of the present invention, Fig. 2 is an explanatory diagram showing an auxiliary cathode, and Fig.
The figure is a characteristic diagram showing the relationship between the thickness of the electrode plating film and the position on the semiconductor substrate, and FIG. 4 is an explanatory diagram showing the configuration of an electrolytic plating bath used in the conventional method. 11... Semiconductor substrate, 12... Electrolytic plating tank, No. 3
... Electrolyte, 14... Anode, 15... Auxiliary cathode,
16m. 16b...Power supply. Applicant's agent Patent attorney Takehiko Suzue Figure 1 (A) (B) Figure 2

Claims (1)

[Claims] A semiconductor substrate is immersed as a cathode in a predetermined electrolytic solution, an anode is immersed so as to face the surface of the semiconductor substrate, and an auxiliary cathode is arranged concentrically with the semiconductor substrate within a plane containing the semiconductor substrate. 1. A method of manufacturing a semiconductor device, comprising: immersing the anode, the auxiliary cathode, and the semiconductor substrate, and applying a predetermined voltage between the anode, the auxiliary cathode, and the semiconductor substrate to form an electrode plating film on the surface of the semiconductor substrate.