JPH0199216A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To press a heated thin film by a pressurizing roller to a semiconductor substrate and to bury a recess formed on the substrate by heating the substrate and the roller, and moving one of the substrate and the roller. CONSTITUTION:A thin film 12 of aluminum series conductor is placed on a semiconductor substrate 11, and the substrate 11, the film 12 and a pressurizing roller 20 are heated to 150-500 deg.C. At least one of the substrate 11 and the roller 20 is moved, thereby pressing the film 12 to the substrate 11 by the roller 20. Then, the film 12 is easily fluidized by heating it, and the film 12 is plastically deformed by pressurizing it. The film 12 is buried in a recess not covered with an insulating layer 23 as much as possible, thereby obtaining a wiring layer 2 having a flat upper face. Thus, the recess formed on the substrate 11 is buried.

Description

[Detailed Description of the Invention] [Summary] A method for forming an aluminum-based wiring layer for forming wiring on a semiconductor substrate, which fills a recess formed in a semiconductor substrate and forms a wiring layer with a flat top surface. A thin film of aluminum is deposited or mounted on a semiconductor substrate, the semiconductor substrate, the thin film, and a pressure roller are heated to 150 to 500°C, and at least one of the semiconductor substrate and the roller is moved. The heating thin film is pressed against the semiconductor substrate using a heating roller.

[Industrial application field]

The present invention relates to a method for forming an aluminum-based wiring layer in the manufacture of semiconductor devices, and in particular, to a semiconductor substrate having unevenness due to a selectively patterned insulating layer, etc., the unevenness is filled to form an aluminum-based wiring layer with a flat upper surface. The present invention relates to a method for forming.

[Conventional technology]

Aluminum (AI)-based conductors are generally used for wiring in semiconductor devices such as ICs and LSIs, and a magnetron sputtering device is generally used to form the AI-based wiring layer to form the wiring, which is about 1IIIll thick. . However, when the wiring layer is simply formed using a magnetron sputtering device on a semiconductor substrate that has unevenness due to patterning of an insulating layer, etc., the wiring layer becomes thinner at the bottom and side surfaces of the contact hole, and the allowable current value There were drawbacks such as a reduction in the number of wires and a cause of wire breakage.

Figure 4 shows an AA film on a semiconductor substrate on which an insulating layer has been patterned.
This is a cross-sectional view of a wiring layer 3 formed by forming an Aβ wiring layer 3 using a magnetron sputtering device or the like on a semiconductor substrate 1 on which 4kN2 is formed in a desired pattern.

In the insulating layer 2, a recess, for example, a contact hole 4, is formed before forming the wiring layer 3, and the wiring layer 3, which is not flattened by bias sputtering, has an overhang above the contact hole 4 as shown in the figure. is generated and becomes thinner at the bottom and side surfaces of the contact hole 4.

Therefore, in the past, the generation of overhang was suppressed by forming the contact hole 4 into a wide trapezoidal opening or applying a bias sputtering method when forming the wiring layer 3. The wiring layer 3 was deposited in order not to become thin.

[Problem that the invention seeks to solve]

However, in the conventional method of suppressing the generation of overhang, it is difficult to make the contact hole trapezoidal enough to eliminate the effect of overhang. As the time required to form the contact hole 4 increases, the temperature of the semiconductor substrate increases, which impairs the fineness and uniformity of the structure of the wiring layer, makes the film thickness non-uniform, and creates a recess above the contact hole 4. As a result, there is a problem in that the miniaturization and precision of wiring patterns are impaired, and a new means has been desired.

[Means for solving problems]

According to the method of the present invention aimed at eliminating the above-mentioned problems, as shown in FIG. 1, a thin film 12 of an aluminum conductor is deposited (or mounted) on a semiconductor substrate 11.
2 and the pressure roller 20 are heated to 150 to 500°C, at least one of the semiconductor substrate 11 and the roller 20 is moved, and the heating thin film 12 is pressed against the semiconductor substrate 11 by the heating roller 20. This is a method for manufacturing a semiconductor device.

[Effect]

According to the above means, heating facilitates the flow (plastic deformation) of the thin film, and applying pressure causes the thin film to be plastically deformed, and the recesses in the semiconductor substrate, which are generally formed to a depth of about 1 μm, are formed in the thin film. Plastic deformation ensures that the wiring layer is filled in, and the upper surface of the wiring layer formed by plastic deformation of the thin film is flattened. Therefore, the present invention improves the accuracy of mask alignment for removing unnecessary portions of wiring layers, and contributes to the formation of fine, high-density wiring.

〔Example〕

Examples of the method of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view schematically showing a flattening press device for a conductive thin film according to an embodiment of the method of the present invention, FIG. 2 is a side sectional view of the main part of a sample according to an embodiment of the method of the present invention, and FIG. FIG. 7 is a side cross-sectional view of a main part of a sample according to another embodiment of the method of the present invention.

In FIG. 1, a semiconductor device substrate 11 has an Al-based thin film 12 formed (sputtered) or mounted on its upper surface, and is fixed to a holder 13 having thermal conductivity, and the holder 13 is fixed to a stage 14 that can move left and right. . Stage 14 is holder 1
For example, the holder 1 has a heater 15 facing the lower surface of the holder 1.
A heater 15 whose energization is controlled by a temperature sensor attached to
Heat to.

Above the stage 14, a support fitting 18 hangs down from the fixed member 16 via a coil spring 17 for pressurization, and a rotating shaft 19
The roller 20, which is rotatable and has a built-in heater, is supported by the support fitting 18 by the roller 20, and when the fixing member 16 is lowered by an appropriate amount or the stage 14 is raised, the thin film 1
2 is pressed against the substrate 11, and the pressing force is generated by the anti-t8 force of the coil spring 17.

Therefore, the substrate 11, thin film 12, and roller 20 were
After heating to ~600°C and causing the roller 20 to press the thin film 12 with a pressing force of 50 to 200 kg/cni, the stage 14 is moved left and right, or the roller 20 is moved left and right. The thin film 12, which has been softened and easily plastically deformed by the heating, fills the recesses formed in the substrate 11 by the pressing force and has a flattened upper surface, thereby obtaining a wiring layer from which unnecessary portions are removed in subsequent steps. It turns out.

In FIG. 2, a semiconductor substrate 1 has an insulating layer 23 made of silicon dioxide (SiO□) selectively formed on its upper surface.
1, an Al-based conductive thin film 12 is deposited using a Macnetron sputtering device, and then the thin film 12 is pressed with the roller 20 described above, and the thin film 12 covers the recesses where the insulating layer 23 is not deposited. Thus, a wiring layer 21 with a flat top surface is obtained. However, the thickness of the wiring layer 21 is set to 1. In this case, the thickness t2 of the thin film 12 is thickened by an appropriate amount in consideration of the amount used for leveling to fill the recess, for example, the thickness t2.
When l is 1 μm, it is necessary to form 1° to 1.6 μm.

In FIG. 3, an Aβ-based conductor sheet (thin film) 22 is placed on a semiconductor substrate 11 on which an insulating Ji 23 is selectively formed.
When the sheet 22 is pressed with the roller 20 described above, the sheet 22 completely fills the recesses where the insulating layer 23 is not adhered, and becomes a flat wiring layer 21 on the upper surface. However, when the thickness of the wiring layer 21 is tl, the thickness t of the sheet 22 is thickened by an appropriate amount in consideration of the amount used for leveling to fill the recess, for example, the thickness tl is 1 μm. The thickness t needs to be 2 to 4 μm.

〔Effect of the invention〕

As explained above, according to the present invention, the flow (plastic deformation) of the thin film is facilitated by heating, and the thin film is plastically deformed by applying pressure. The spots are reliably filled by plastic deformation of the thin film, and the upper surface of the wiring layer formed by plastic deformation of the thin film is flattened. As a result, mask alignment for removing unnecessary portions of the wiring layer becomes more accurate, which has the effect of contributing to the formation of fine and high-density wiring.

[Brief explanation of the drawing]

FIG. 1 is a side view schematically showing a flattening press device according to an embodiment of the method of the present invention, FIG. 2 is a side sectional view of the main part of a sample according to an embodiment of the method of the present invention, and FIG. 3 is a method of the present invention FIG. 4 is a side cross-sectional view of a main part of a sample according to another embodiment. FIG. 4 is a cross-sectional view of a wiring layer formed on a semiconductor substrate on which an insulating layer is patterned. In the figure, 11 is a semiconductor substrate, 12 is a thin film of aluminum conductor, 15 is a heater, 20 is a pressure roller, 21 is a wiring layer of aluminum conductor, 22 is a sheet (thin film) of aluminum conductor, and 23 is an insulating layer. , indicates. J4 diagram

Claims (1)

[Claims] A thin film of aluminum conductor (
12, 22) is adhered or mounted, and the semiconductor substrate (11
), the thin film (12, 22), and the pressure roller (20) are heated to 150 to 500°C, and at least one of the semiconductor substrate (11) and the roller (20) is moved to remove the heating roller (20). A method for manufacturing a semiconductor device, characterized in that the heating thin film (12, 22) is pressed against the semiconductor substrate (11).