JPS62247083A - Treatment of metal - Google Patents

Abstract

PURPOSE:To easily obtain a film having high accuracy in thickness by chemical conversion treatment by preheating a metal to a temp. close to the chemical conversion treatment temp. CONSTITUTION:A semiconductor wafer 1 having metallic wiring of an Al-Si alloy or the like on a substrate of Si or the like is vertically fixed in a basket 2 and the basket 2 is moved to a preheater 9 over a soln. 7 for chemical conversion treatment heated beforehand to a prescribed temp. with heaters 5. The wafer 1 is then preheated to a proper temp. with the preheater 9 and the basket 2 is moved so that the wafer 1 is completely immersed in the soln. 7. After treatment is carried out for a prescribed time, the basket 2 is pulled up from the soln. 7 and dried. The metal is preferably preheated to a temp. nearly equal to the prescribed temp. of the soln. 7. The metal is preferably a passive metal such as Al, Ni, Ti, Co, Ta or Nb or an alloy thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for treating metals, and in particular to a method for producing a chemical conversion treatment film thereof.

[Conventional technology]

FIG. 3 is a cross-sectional view showing a conventional manufacturing apparatus for manufacturing a chemical conversion film, in which (1) is a semiconductor wafer, (2) is a semiconductor wafer, and (2) is a semiconductor wafer.
) is a basket made of a material with good heat retention, such as tear iron, to support this semiconductor wafer (2), (3I is a handle detachably attached to this basket (2), and 14
) is the liquid tank that collects the liquid ()), (5) is the heater that heats the liquid +7) and keeps it warm, (6) is the bath mentioned above, and f! I
The drainboard supporting the slats, (7) is a chemical conversion treatment liquid necessary for chemical conversion treatment.

Next, the operation will be explained. A room temperature semiconductor wafer (11) with aluminum wiring is attached to a Teflon basket (2), a handle (3) is attached to the basket (2), and the basket (2) is moved above the liquid tank +4. (For example, pure water) (7) is heated and kept warm at a constant temperature of 80° C. using a heater (5).

Next, lower the handle (31) so that the semiconductor wafer 111 is completely immersed in the liquid (with the handle 131 attached to the basket).
put a hat on top This state is maintained for several minutes to 80 minutes to form an aluminum water conserving oxide film on the aluminum wiring. Then, using the handle (31), raise the wafer (Pasquera) l ft to remove Ueno 111+ completely from the liquid, stop the chemical conversion reaction, and remove it from the spin dryer (
(not shown) or the like.

The relationship between the film thickness and time of the aluminum water-conserving oxide thus formed shows growth as shown in FIG. As you will see, there is a point where the growth of the film changes significantly. Furthermore, the area of B is proportional to approximately the fifth power of time. In other words, this means that immediately after a low-temperature semiconductor wafer is placed in a high-temperature chemical conversion solution, the B region grows in a reaction rate-determined manner because it has not yet reached the processing temperature, and the B region grows in a diffusion-determined manner after reaching the processing temperature. It seems to be for growth. Unfortunately, in the conventional method, the film thickness could not be accurately controlled because the region A changes depending on the temperature before the chemical conversion treatment of the semiconductor device.

[Problem that the invention seeks to solve]

Since the conventional manufacturing method is performed as described above, the chemical conversion treatment temperature of the metal is not maintained at a predetermined value as a result. Therefore, the thickness of the chemical conversion treatment film formed becomes unstable even if the temperature of the chemical conversion treatment solution is set, making it difficult to form the film with high precision.

This invention was made to solve the above-mentioned problems, and its object is to easily form a thin layer with high accuracy by chemical conversion treatment.

[Means for solving problems]

The metal processing method according to the present invention is such that the metal is preheated to a temperature close to the chemical conversion treatment temperature before the metal is subjected to the chemical conversion treatment.

[Effect]

Since the preheating step in the present invention heats the metal so as to bring it close to the chemical conversion treatment temperature, the chemical conversion treatment film can be formed with high precision.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 8g1
The figure is a process flow diagram, and this will be explained using FIG. 3 showing the manufacturing apparatus.

In Figure 3, ... is aluminum silicon (alloy)
A semiconductor wafer with wiring, fil, is a basket in which the wafer (1) is mounted, and this basket is made of Teflon or the like, which has good heat retention.

(31 is a handle that can be attached to and removed from the basket +2), and this handle (31 is also made of Teflon, etc., like (2). (4) is a liquid tank for storing the chemical conversion solution T-. It is also made with Thea0n etc. (5
) is a heater that heats the solution to a desired temperature, (6) is a basket (!1) is a drainboard made of Teflon, etc. that keeps it still in the solution, and (7) is a liquid used for chemical conversion treatment, which is pure water or It is a weak alkaline solution such as ammonia water. (8)
is a shutter that can be opened and closed freely, and +91 is a far-infrared heater that heats the wafer 111.

Next, the operation will be explained. In the ware 1 mounting step (11) shown in FIG. 1, a plurality of semiconductor wafers having aluminum silicon alloy wiring formed on a substrate made of silicon or the like are directly mounted in a basket. Next, in the preheating step 0~, put the no ndol (3) in the basket (!
: Attach to the preheater (9) above the chemical conversion treatment liquid (7)
move it to. At this time, the chemically modified tin 1 liquid (7), for example, pure water, is heated in advance to a temperature of 100° C. with a heater (5), and the shutter (8) is also closed. Then heat the wafer to about 100℃±5 using the preheater (9).
Heat until ℃.

Next, in the chemical conversion process α-hole, the shutter (8) is opened and a Basqueratra slatted filter is applied so that the entire wafer is immersed in the liquid.
Move the handle to the top, close the shutter f81'i, and process for several minutes to 30 minutes to convert the aluminum/silicon alloy wiring into hydrated oxide. When the treatment is finished, open the shutter +81, attach the handle (31) to the basket (2), and place the basket (2) into the liquid (7).
) and close the shutter (8) to complete the reaction. Then, in a drying step H, it is dried using a spin dryer or the like.

In the above embodiment, the surface of aluminum-silicon alloy wiring in a semiconductor device with aluminum-silicon wiring is subjected to chemical conversion treatment, but passive metals such as aluminum, nickel, titanium, chromium, and tantalum, It may also be a semiconductor device that is mainly made of an alloy. Further, although the chemical conversion treatment liquid is shown to be pure water, it may also be saturated steam, a weak alkaline solution such as aqueous ammonia or triethanolamine. Since heating is performed, it is possible to easily obtain a chemical conversion film having a highly accurate film thickness.

[Brief explanation of drawings]

FIG. 1 is a process 70-diagram according to one embodiment of the present invention;
The figure is a cross-sectional side view showing a chemical conversion treatment apparatus suitable for a process according to an embodiment of the present invention, and FIG. 8 is a cross-sectional view showing a chemical conversion treatment apparatus suitable for a conventional process. FIG. 4 is a diagram showing the relationship between the chemical conversion treatment time and the thickness of the water-containing oxide film on aluminum when carried out in a conventional process. 04 indicates the preheating process, and 0th floor indicates the chemical conversion treatment time. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (5)

[Claims] (1) A metal processing method comprising the steps of preheating the metal and performing a chemical conversion treatment on the preheated metal in a chemical conversion treatment solution or atmosphere at a predetermined temperature. (2) A method for treating metal according to claim 1, characterized in that the metal is preheated to approximately the same temperature as a predetermined temperature. (3) The metal is an immobile metal such as aluminum, nickel, titanium, cobalt, tantalum, niobium, or an alloy mainly composed of these. Metal processing methods. (4) Claims 1 to 3, characterized in that the chemical conversion treatment liquid or atmosphere is pure water, steam, saturated steam, a weak alkaline solution such as aqueous ammonia or triethanolamine solution, or an atmosphere thereof. The metal processing method described in any of the above. (5) The metal processing method according to any one of claims 1 to 4, wherein the metal is present on a semiconductor substrate such as silicon.