JPS6153717A - Thin film forming device - Google Patents

Abstract

PURPOSE:To form a thin film without any break in a submicron region through making each incident angle predetermined angle by injecting most of particles from a supply source in the first and the second incident angles with a surface. CONSTITUTION:After a particle supply source generating adhering particles 24 and 25 of thin film forming material in a thin film forming device, these particies 24 and 25 are introduced and adhered to a surface of a thin film forming substrate 1 forming a thin film in a target 27. Most of particles 24 and 25 from this particles supply source are used to the surface of the substrate 1 as the first incident angle being an outside erosion region 22 and as the second incident angle being as an inside erosion region 23. This first incident angle is set at a sharper angle with a surface than the second incident angle, and the second incident angle is set at a sharper angle with a vertical direction of the surface than the first incident angle. After the first incident angle is set as about 15 deg. and the second incident angle is set at about 60-90 deg., a thin film is formed without any break in a submicron region.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a thin film forming apparatus used in the manufacture of semiconductor devices, and in particular to a thin film forming apparatus that can form a thin film with a good coating shape without any breaks even between narrow steps or inside minute through holes. The present invention relates to an apparatus capable of forming a thin film.

[Prior Art] The main thin film forming methods used in the manufacture of semiconductor devices include sputtering, vapor deposition, and CVD. The CVD method is a method in which a gaseous raw material is introduced near the surface on which a thin film is grown (hereinafter referred to as the growth surface), such as the surface of a semiconductor device, and is heated on the growth surface to react or decompose to form a thin film. be.

On the other hand, in the sputtering method and the vapor deposition method, the raw material for the thin film is directly incident on the long surface of the semiconductor device from the supply source as particles that adhere to the surface of the semiconductor device (hereinafter referred to as adhered particles). This is a method of forming a thin film by depositing particles on a surface, and it is widely used as a thin film forming method for semiconductor devices because it can form good 8-holes even when the temperature of the growth surface is lower than that of the CVD method. ing.

The reason why these thin films are formed on the surface of a semiconductor device is to form electrode wiring and an insulating film layer. Incidentally, since elements such as transistors, isolation regions, wiring, and through holes are formed on the surface of a semiconductor device, the surface is uneven. When wiring is formed on such an uneven surface, the unevenness on the surface of the semiconductor device needs to be smoothly covered with an insulating film in order to prevent disconnection or short-circuiting of the wiring. In addition, the eight films for forming wirings themselves need to smoothly cover steps caused by unevenness on the surface of the semiconductor device.

In sputtering and vapor deposition methods, adhered particles are directly incident on the growth surface from the supply source, so if the adhered insulator is incident mainly at a high angle to the growth surface, fewer adhered particles will reach the side walls of the step. The S thickness growing on the sidewall becomes thinner. For this reason,
In the conventional apparatus, as shown in FIG. 2, by lowering the incident angle of the adhered particles 2 onto the thin film growth substrate, for example, the semiconductor device substrate 1, it is possible to form a film with a sufficient thickness even on the side walls of the step. This achieves a smooth coating shape and prevents a drop in yield due to wire breakage or short circuits due to unevenness.

In other words, the height of a step due to unevenness on the surface of a conventional semiconductor device generally ranges from 0.5 p-m to 1.0 p-m.
On the other hand, the distance between the steps and the size of the through hole are 2 m to 3 m or more. Therefore, of the adhered particles that enter between the steps or towards the bottom of the through-hole, the percentage of particles that do not reach the attachment point because they are blocked by the steps around the attachment point or the side walls of the through-hole is very small. .

When a thin film is formed on the surface of a semiconductor device 1 having relatively widely spaced steps such as grooves 3 and through holes 4 as shown in FIG. 3 using a conventional device as shown in FIG. FIG. 4 shows a cross section of the covered shape of the step. In this example, the incident angle of the adhered particles was 45°, and the distance between the surface of the semiconductor device I and the source of the adhered particles was 8 cm. The groove 3 had a depth of 0.5 m, a width of 1 m, and a through hole 4 had a depth of 0.5 m, a width of 1 m, and a depth of l m. In the case of this example, both the bottom of l+1ff 3 and the bottom of the through hole 4 are covered with a thin film having approximately the same thickness as the thickness of the upper part 5 of the step.

However, as the density and miniaturization of semiconductor devices, typified by LSIs, progress, the spacing between interconnections, that is, the spacing between steps and the dimensions of through holes are becoming smaller.

On the other hand, the thickness of the wiring and the depth of the through-hole cannot be reduced from the viewpoint of suppressing wiring resistance, suppressing a drop in breakdown voltage, and suppressing parasitic resistance. When incident from a direction (for example, about 45 degrees), as the spacing between wiring lines and the dimensions of the through hole decrease, the proportion of adhered particles that fly into the groove or through hole that are blocked by the side walls increases. It becomes difficult to adhere to the insides of minute through-holes and grooves, especially the bottoms. This phenomenon becomes noticeable when the ratio of the interval to the depth of the steps becomes smaller than approximately 1, and is one of the causes of a decrease in the yield of LSI.

For example, as shown in FIG. 6, a conventional sputter thin film forming apparatus as shown in FIG. 5 is used to coat a semiconductor surface with fine grooves and through holes with a thin film. Explain the situation.

In FIG. 5, 7 is a target, and 8 is an invasion fFl! formed on the surface of the target 7 by sputtering the target 7. The attached particles 9 from this erosion region 8 enter the surface of the semiconductor device 1 on which a thin film is formed in the direction of the arrow. Here, the substrate l
The distance between the surface of the semiconductor device 1 and the target 7 was set to 8CI11, and the position of the erosion region 8 was set so that the incident angle of the attached particles to the surface of the semiconductor device 1 was 45°. As shown in FIG. 6, the surface of the semiconductor device 1 has a depth of 0.
5 pm, width 0.5 g m groove 10, depth 0.5 p
-rn, width 0.5gm+, depth 0.5p-m
It is assumed that a through hole 11 is formed.

In this case, the shape of the thin film coating on the surface of the semiconductor device 1 is shown in cross section as shown in FIG.
Although the film is attached to the bottom of the groove 10 and the through hole 11, almost no film is attached to the bottom of the groove 10 and the through hole 11. As can be seen by comparing Fig. 4 and Fig. 7, using the conventional thin film forming equipment, the submicron film as shown in Fig. 8
It is difficult to cover custom-ordered grooves and through-holes without any breaks.

In addition, recently, bias sputtering has been applied to semiconductor devices and
Techniques for flattening the unevenness of the SI surface are increasingly being used. This method can prevent wiring breakage on uneven steps and is effective in improving LSI yield. The bias sputtering method is a sputtering method in which a thin film is formed and at the same time, a bias is applied to the growth surface side where t'='j n's is formed, and Ar ions are incident perpendicularly to perform etching. be. With the bias sputtering method, as mentioned above, it is possible to flatten the surface of the film to be etched that is inclined (hereinafter referred to as the "slanted surface") compared to the surface of the film to be etched that is parallel to the growth surface (hereinafter referred to as the "parallel surface"). For example, if the bias conditions are set so that the film formation speed on a parallel surface is the same as the sputter etching speed on a parallel surface, the etching speed will be lower on an inclined surface. As a result, the slope recedes and the step is flattened.

However, as described above, when the interval between the steps becomes narrower, it becomes difficult for a film to grow on the bottom. On the other hand, if a bias is applied to the growth surface due to bias sputtering, A
The r ions are incident perpendicularly. Therefore, even if the bottom of a narrow step is a parallel surface, the etching becomes larger and cannot be flattened by the mechanism described above.The same can be said of through holes.

As mentioned above, when using conventional sputtering equipment or vapor deposition equipment that is designed so that the adhered particles fly diagonally in consideration of the coverage of steps, it is difficult to This means that the through holes cannot be well coated. This is becoming a very serious problem as LSIs become smaller and more dense.

[Objective of the Invention] Therefore, the object of the present invention is to form GFi nQ also on the bottom of the groove formed by the step of the wiring, etc. and the bottom of the fine through hole as described above, and to form GFi nQ evenly on the sidewall of the step. An object of the present invention is to provide a thin film forming apparatus capable of coating a thin film.

Another object of the present invention is to provide a thin film forming apparatus in which the incident angle distribution of particles adhering to the surface of a semiconductor device with respect to the surface of the semiconductor device is optimized.

[Means for Solving the Problem] In order to achieve the above object, the present invention has a particle supply source that generates particles of a thin film forming raw material, and introduces and attaches one particle to a surface on which a thin film is to be grown, so that the particles are deposited on the surface. In a thin film forming apparatus that forms a thin film, most of the particles from the source are applied to the surface in a small amount, at least in the first and second portions.
The first incident angle is set closer to the surface than the second incident angle, and the second
The incident angle of the first incident angle is set to be more perpendicular to the surface than the first incident angle.

[Example] The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an example of the basic configuration of the present invention. In this embodiment, a target 21 is provided with two outer lotion regions 22 that provide a distribution in the incident direction of attached particles 24, and in addition, a semiconductor device An inner erosion region 23 into which adhered particles 25 are incident in a direction close to perpendicular to the first surface is provided in a ring shape approximately concentrically with the outer two lotion regions 22.

In this example, while the target 21 and the growth surface 1 are kept parallel to each other during film formation, their mutual positions are indicated by the arrow 28.
By varying the angle as shown in and 27, variations in the incident angle distribution of the attached particles on the growth surface 1 can be reduced. i Here, FIG. 8 shows a cross section of the coating shape when the surface of the semiconductor device shown in FIG. 6 is coated with the apparatus shown in FIG. The distance between the surface and the target 21 is the same as in FIG.
was determined so that the incident angle of the attached particles 25 was 75°. As shown in FIG. 8, at the bottom of the groove 10,
A film thickness of 70% or more of 2 and a film thickness of <60% or more at the bottom of the through hole 11 were obtained, and the formation of a uniform thin film was significantly improved over the conventional example shown in FIG.

Using the apparatus of the embodiment shown in FIG. 1, the outer erosion region 22 of the target 21 is set so that the incident angle is 45°, and the inner erosion region 23 is changed in position. Adhesive particles 25 from
FIG. 9 shows the relationship between the incident angle and the ratio of the film thickness at the bottom of the groove 10 or through hole 11 to the film thickness at the top 12 of the step.

Here, the attached particles 2 from the inner erosion region 23
The higher the incident angle of the groove 10, the thicker the PQ thickness at the bottom of the through hole 11.9For example, when the incident angle is around 456, particles hardly adhere to the bottom of the through hole 11, 30 also at the bottom
It is about %. When the incident angle is 60°, 40% of the particles adhere to the bottom of the groove 1O and 10% of the particles adhere to the bottom of the through hole 11. The incident angle was further increased to 75°.
In this case, 70% of the particles will adhere to the bottom of the groove 10 and 60% or more of the particles will adhere to the bottom of the through hole 11.

Note that the proportion of adhered particles that are incident from a high angle of incidence decreases at a position extending from just below the inner erosion region 23. Therefore, the position of the inner two lotion regions 23 is determined based on Pj, the size of the substrate 1 on which a thin film such as a semiconductor device is grown, and the allowable film thickness between the bottom of the groove 10 or the bottom of the through hole 11. It can be determined based on the variation in .

In the embodiment described above, the erosion regions 22 and 23 are distributed in a circular shape to form a double ring, but the number of rings may be further increased, or alternatively, the two lotion regions may be Instead of a shape, the particles may be distributed in a dotted manner, for example, in a matrix shape.

In the case of the above embodiment, if the ratio of the obliquely incident particle component 24 and the high angle incident particle component 25 is approximately 1:1, the two lotion area distribution can be appropriately determined from the incident angle. Note that the ratio of 1:1 is not necessarily required here, and this ratio can be changed depending on various conditions. Almost the same result can be obtained by making the adhered particles alternately incident from each direction, instead of making almost the same amount of adhered particles incident at the same time from a high incidence angle and a low incidence angle as in the above-described embodiment. In that case, the amount of incident particles per unit time from both may be made different. In that case, the amount of attached particles from each direction can be adjusted by adjusting the incident time from each direction. In this way, as long as the above-described relationship between the angle relationship and the incident amount is satisfied, the above-described control of the incident direction and incident amount can be performed in the type/7 form.

In the above example, the incident angle of the incident particles was controlled by appropriately determining the distribution of the two lotion regions.Next, an appropriate shielding mechanism was provided in front of the growth surface of the thin film, e.g. An embodiment of the present invention in which the incident angle is controlled is shown in FIGS. 1O and 11. Incidentally, since the wood embodiment does not depend on the method of supplying the deposited particles, it can be applied not only to sputter deposition but also to the 1-layer deposition method.

FIG. 10 shows an embodiment of this kind suitable for a raw material supply source with many incident components from a low angle. A shielding plate 31 is provided. This shielding plate 31
, through holes 32 with a diameter tl are opened at intervals t3. Note that these through holes 32 can be arranged in a matrix or concentrically. Alternatively, the through hole 32 may be rectangular instead of circular, or may be a concentric ring-shaped opening, or an elongated opening formed by juxtaposing slits, struts, or ribs.

In the embodiment shown in FIG. 1O, the attached particles 33 that are incident from a direction perpendicular to the surface of the substrate 1 reach the growth surface of the substrate 1, but the attached particles 34 and 35 whose incident angle is low
The thickness t2 of the shielding plate 31 is the size tl of the through hole 32.
The larger the angle is, the smaller the proportion reaching the growth surface, and therefore the incident component from a relatively high angle can be increased, thereby achieving the same effect as the embodiment shown in Figure 1. It will be done.

FIG. 11 shows an embodiment that is effective for a raw material supply source with many incident components from high angles. In this example, a first shielding plate 41 is placed on the target side at an appropriate distance dl from the surface of the substrate 1. and a distance #1 from this first shielding plate 41.
A second shielding plate 42 is disposed on the target side at a distance of d2. The shielding plates 41 and 42 each have a distance t4.
At t5, the adhered particles 45 entering the through holes 43 and 44 with diameters t6 and t7 alternately are prevented from reaching the surface of the substrate 1 by two shielding plates 415 and 42. However, the attached particles 46 and 47 that are incident obliquely can enter the surface of the substrate 1. The smaller the distance f4d2 between the shielding plates 41 and 42, and the larger the overlap 78 between the page through holes 43 and 44, the more obliquely incident components 46 and 47 can be relatively increased. Thus, the same effects as the embodiment shown in FIG. 1 can be obtained.

In the embodiments of FIGS. 10 and 11, the growth surface,
Although the relative positional relationship between the raw material supply source such as the target and the shielding plate may be fixed, the relative positional relationship between the substrate l, the shielding plates 31 or 41 and 42, and the raw material supply source such as the target may be changed during film formation. can also be varied as shown by arrows 26 and 27. By varying the relative positional relationship during thin film formation in this way, the raw material particles are
Average the distribution of angles incident on each position on the growth surface of
A coating shape as shown in FIG. 8 can be obtained at any position on the growth surface.

[Effects of the Invention] As explained above, the present invention provides a thin film forming device such as a sputtering device and a vapor deposition device that can coat the inside of a minute through hole or between a minute groove well. can do. In particular, the present invention provides through-hole and
A greater effect is exhibited in that a thin film can be seamlessly formed in a region where the width of the film is smaller than its depth, specifically, in a submicron region. Therefore, by introducing the present invention into the thin ++q formation process of submicron LSI, it is expected that the yield of wiring will be improved more than when using conventional equipment.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an embodiment of the thin film forming apparatus of the present invention, and Figure 2 is a diagram showing a conventional thin film forming apparatus in which particles attached to a surface on which a thin film is grown, such as the surface of a semiconductor device, are incident obliquely. A diagram schematically showing the situation. Figure 3 is a perspective view showing grooves and through-holes on the semiconductor surface viewed diagonally from above.
i: Wj h! Yes, it's a perfect fit. Thin film. A cross-sectional view showing the cover shape taken along line AB in Figure 3, Figure 5 is a line diagram schematically showing the relationship between the target of a conventional sputtering device and a substrate for thin film growth, and Figure 6. is a perspective view showing submicron grooves and through-holes on the surface of a semiconductor, viewed diagonally from above. Figure 7 shows the coating shape when a thin film is formed on the grooves and through holes in Figure 6 using the conventional device shown in Figure 5.
8 is a cross-sectional view taken along line AB in the figure, and FIG. 8 is a cross-sectional view taken along line AB in FIG. The cross-sectional view shown in Figure 9 shows the relationship between (thickness at the bottom)/(film thickness at the top of the step) of the groove or through-hole for a high incident angle when the oblique incident angle is 45°. Fig. 10 is a cross-sectional view showing another example of the present invention used in a thin film forming apparatus having a raw material supply source with many obliquely attached particles; Fig. 11 FIG. 2 is a cross-sectional view showing an embodiment of the present invention used in a thin film forming apparatus having a raw material supply source with many particles adhering from the vertical direction. l...78J film growth substrate, e.g. semiconductor device, 2.
... Adhering particle, 3... Groove, 4... Through hole, 5... Upper part of step, 7... Target, 8... Erosion area, 3... Adhering particle, ' 10...・l+1ff, +1...Through hole, 12...Top of step, 21...Target, 22...Outer two lotion areas, 23...Inner erosion area, 24.25...Adhesive particles, 26.27...Arrows schematically showing variations in the target, growth surface, and shielding plate, 31.41.42...Shielding plate, 32.43.44...Through hole, 33.34,35, 45.4ft, 4? ... Adhesive particles.

Claims (1)

[Claims] 1) having a particle supply source that generates particles of a thin film forming raw material;
In a thin film forming apparatus for introducing and depositing the particles onto a surface on which a thin film is to be grown to form a thin film on the surface, a majority of the particles from the source are directed to at least a first and a second layer on the surface. the first incident angle is set closer to the surface than the second incident angle, and the second incident angle is set closer to the surface than the first incident angle. A thin film forming apparatus characterized in that the film is formed on a side perpendicular to a surface. 2) The thin film forming apparatus according to claim 1, wherein the first incident angle is approximately 45 degrees and the second incident angle is between 60 degrees and 90 degrees. 3) In the thin film forming apparatus according to claim 1 or 2, the supply source has a target formed from the thin film forming raw material, and the particles are generated by sputtering the target; A plurality of eroded regions are formed on the surface of the target by the sputtering, and the eroded regions are distributed such that the generated particles are incident on the surface at least at the first and second incident angles. A thin film forming device featuring: 4) In the thin film forming apparatus according to any one of claims 1 to 3, the relative positional relationship between the surface and the particle supply source is made parallel to each other during thin film formation. A thin film forming apparatus characterized in that the incident angle of particles incident on the surface is varied by continuously changing the incident angle. 5) In the thin film forming apparatus according to claim 1 or 2, between the particle supply source and the surface,
A thin film forming apparatus comprising a shielding plate having a plurality of through holes through which the particles pass. 6) In the thin film forming apparatus according to claim 5, a plurality of the shielding plates are arranged parallel to the surface,
A thin film forming apparatus characterized in that the through holes of each shielding plate are arranged alternately. 7) In the thin film forming apparatus according to claim 5 or 6, the relative positional relationship of the particle supply source, the shielding plate, and the surface is continuously varied in directions parallel to each other, A thin film forming apparatus characterized in that the incident angle of particles incident on the surface is varied.