JPH0511435U - Asssing device - Google Patents

Abstract

(57) [Abstract] [Purpose] In an ashing device using a dielectric line, the hole forming area of the partition wall is set at a position corresponding to the ashing target, and the resist is uniformly ashed. [Structure] A plasma generation chamber 14 and an ashing chamber 15 in which a sample (wafer) S to be ashed is placed in the reactor 1.
A region for forming a plasma introduction hole 17 to be provided in the partition wall 13 for partitioning the space is set to be substantially the same size as the region corresponding to the sample in the ashing chamber 15.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an ashing device for ashing and removing an organic resist film used in a process of manufacturing a semiconductor product by using a plasma.

[0002]

[Prior Art]

 In the process of manufacturing semiconductor products such as semiconductor integrated circuits, a resist is widely used as a mask for etching, but this resist needs to be removed after the etching is completed. As a method for removing the resist, conventionally, a wet process using a liquid chemical and a dry process using plasma or the like are known.

However, in the wet processing, the quality of the semiconductor product produced is poor due to contamination of the wafer surface by impurities in the chemicals and the loss of the created patterns, and the working efficiency is poor due to the large amount of chemicals used. There are some difficulties. Under these circumstances, dry processing is widely used in which the resist is ashed and removed using plasma.

FIG. 3 is a schematic cross-sectional view showing the configuration of a plasma ashing apparatus which is a conventional dry processing apparatus. In the figure, 21 indicates a barrel type reactor made of a quartz tube. A gas introduction pipe 22 for introducing O ₂ gas into the reactor 21 and an exhaust pipe 23 for exhausting the gas in the reactor 21 are connected to the reactor 21.

A ground electrode 24 is provided above the reactor 21, and a high frequency electrode 26 connected to a high frequency power supply 25 is provided below the reactor 21 so as to face the ground electrode 24. In the reactor 21, a plurality of samples (wafers) S to be ashed are vertically arranged in rows at substantially equal intervals.

Next, the operation will be described. After the inside of the reactor 21 is set to a predetermined vacuum state, O ₂ gas is introduced into the reactor 21 through the gas introduction pipe 22 and a plasma is generated by applying a high frequency electric field to the reactor 21 to generate a plurality of samples S. The resist on the surface of is removed by ashing.

The ashing apparatus described above has an advantage of high work efficiency because it can perform resist removal processing on a large number of wafers at a time, but on the other hand, if the entire semiconductor product is exposed to plasma and the semiconductor product becomes fine, semiconductor There is a drawback that the damage of the product becomes large and the quality of the manufactured product deteriorates.

In order to eliminate such drawbacks, ashing devices disclosed in Japanese Patent Laid-Open Nos. 62-99481 and 62-5600 proposed by the present applicant are known. This assembling apparatus has a structure in which the upper wall of the reactor is sealed with a heat-resistant plate capable of transmitting microwaves, and a dielectric line into which microwaves are introduced is formed above the heat-resistant plate.

A partition wall is arranged inside the reactor of the ashing device in parallel with the heat resistant plate, and is separated into an upper plasma generation chamber and a lower ashing chamber. This partition wall is provided with multiple holes, and among the plasma generated in the plasma generation chamber, the partition wall dams the charged particles, and only radicals are supplied to the ashing chamber through this hole. The sample (resist on the wafer) placed in the chamber is ashed. Such an ashing device has the advantages that the processing area is large and the plasma source and the microwave source can be easily matched.

Further, the present applicant has proposed an ashing device, which is a further improvement of the device utilizing the above-mentioned dielectric line, in Japanese Patent Laid-Open No. 2-141576. In this device, a space for making the plasma density uniform is provided in series with the plasma generation chamber so that the uniformity of the ashing process can be improved and the charged particles can be removed.

[0011]

[Problems to be solved by the device]

 By the way, in such an ashing device, it has been confirmed that changing the distribution of holes in the partition wall changes the uniformity of the ashing speed, but the hole in the partition wall for performing ashing with excellent uniformity is confirmed. There was no established technique for setting the distribution of.

The present invention has been made in view of the above circumstances, and provides an ashing apparatus capable of performing uniform ashing treatment on a sample by specifying a distribution area of holes in a partition wall. The purpose is to

[0013]

[Means for Solving the Problems]

 An ashing device according to the present invention comprises a waveguide for transmitting microwaves, a dielectric line connected to the waveguide, and a reactor arranged to face the dielectric line. A plurality of holes are provided to separate the inside of the plasma generation chamber for generating plasma and the ashing processing chamber having a mounting table on which the ashing target is placed, and for communicating the plasma generation chamber with the ashing processing chamber. In the assembling apparatus having the partition wall provided, the distribution area of the holes of the partition wall is substantially the same as the size of the ashing target.

[0014]

[Action]

 In the present invention, the ashing speed is increased and the ashing uniformity is improved by setting the distribution area of the holes for plasma introduction provided in the partition wall to correspond to the sample.

[0015]

【Example】

 Hereinafter, the present invention will be specifically described with reference to the drawings showing an embodiment thereof. FIG. 1 is a schematic cross-sectional view showing the structure of an ashing device according to the present invention. In FIG. 1, reference numeral 1 denotes a hollow rectangular parallelepiped-shaped reactor, which is made entirely of metal except an upper wall, and in particular a surrounding wall is It has a heavy structure and has a flow-through chamber 11 for cooling water inside. The upper wall of the reactor 1 is permeable to microwaves, and is hermetically sealed with a heat-resistant plate 12 made of a material having a small dielectric loss, such as quartz glass or Pyrex glass.

Above the reactor 1, an aluminum plate 2a having a size that can cover the upper surface of the reactor 1 with a predetermined space between the heat resistant plates 12 is formed on the lower surface of the aluminum plate 2a. The dielectric line 2 is formed by arranging a dielectric layer 2b such as polyethylene. A microwave oscillator 6 is connected to a side portion of the dielectric line 2 via a waveguide 5, and the microwave oscillated from the microwave oscillator 6 is introduced into the dielectric line 2 via the waveguide 5. Thus, an electric field necessary for generating plasma is formed in the reactor 1.

The inside of the reactor 1 is divided into an upper plasma generation chamber 14 and a lower ashing treatment chamber 15 by a partition wall 13 arranged in parallel with the heat resistant plate 12 at a position near the upper wall. A gas supply pipe 3 for supplying a process gas is connected to the plasma generation chamber 14 through the peripheral wall from the same side as the waveguide 5, for example.

On the other hand, in the ashing processing chamber 15, an exhaust port 4 connected to an exhaust pump (not shown) is opened on the bottom wall surface facing the partition wall 13, and in the ashing processing chamber 15, a sample S, which is a wafer to be ashed, is sampled. A mounting table 16 for mounting the is installed in parallel with the partition wall 13 at a distance of d (= 40 to 60 mm) from the partition wall 13.

The partition wall 13 is formed of a microwave shielding material, for example, a metal plate such as stainless steel or aluminum, and is divided into a plurality of areas in a region corresponding to the mounting table 16, more strictly in a region corresponding to the sample S. A hole 17 is provided, and through this hole 17, neutral particles such as radicals in the plasma generated in the plasma generation chamber 14 are led out to the ashing processing chamber 15 and directed toward the surface of the sample S.

A large number of holes 17 are formed in a position corresponding to the sample S in a region of approximately the same size as the shape of the sample S. For example, when the sample S is circular or rectangular, the formation region of the hole 17 is also circular or rectangular, and is formed in a region of approximately the same size as the sample S. Although the size of each hole 17 is not particularly limited, it is preferably about 1 to several mm for uniform introduction of plasma.

The partition wall 13 is located in the reactor 1 above the site where the gas supply pipe 3 is connected, and the microwave shielding members 14c and 14d having an L-shaped cross section are fixed to the peripheral edge of the partition wall 13. The respective edge portions are connected to the wall surface portion below the position where the gas supply pipe 3 of the plasma generation chamber 14 is connected. As a result, a space 14a extending from the partition wall 13 toward the ashing chamber 15 is formed in the periphery of the partition wall 13 so as to be continuous with the plasma generation chamber 14 along the peripheral wall.

Next, the operation will be described. The microwave oscillated by the microwave oscillator 6 is introduced into the dielectric line 2 through the waveguide 5, passes through the heat resistant plate 12, and is introduced into the plasma generation chamber 14. On the other hand, the gas supplied from the gas supply pipe 3 is first stored in the space 14a, spreads over the entire space 14a, and then flows evenly on the partition wall 13 inside the plasma generation chamber 14 excluding the space 14a. The plasma is generated by being introduced into the plasma generation chamber 14 in the state where the local pressure difference at is eliminated. This plasma is uniformly led to the ashing chamber 15 through the holes 17 in the partition wall 13. At this time, most of the charged particles are trapped by the partition wall 13, and only neutral particles such as radicals reach the surface of the sample S mounted on the mounting table 16 and the ashing process is performed on the resist.

(Test Example) As a sample S, a wafer having a diameter of 150 mm having a resist coated on the entire surface is used, and as the partition wall 13, holes 17 having a diameter of 2 mm are arranged at a pitch of 5 mm corresponding to the center of the mounting table 16. We prepared three patterns with a large number of circles with diameters of 130 mm, 150 mm, and 200 mm centered on the position. The partition walls 13 of these three patterns are alternately used, O ₂ and CF ₄ gas are supplied through the gas supply pipe 3, ashing treatment is performed under the following treatment conditions, and after a predetermined time, the resist thickness on the wafer surface Was measured to determine the removal rate (μm / min). Microwave power 1.5 kV O ₂ gas flow 740 sccm CF ₄ gas flow 60 sccm Wafer temperature 30 ℃

The results are shown in FIG. Figure 2 is a graph showing the relationship between the distribution area of holes drilled in the partition wall and the resist removal rate. The horizontal axis shows the distance from the wafer center (mm), and the vertical axis shows the removal rate (μm / min). It is shown. In the graph, the circles are plotted when the holes are formed in the area of 150mm centered on the position facing the wafer center, and the squares are plotted in the same area for the holes of 130mm. The plots with triangles show the cases where holes were formed in the area of 200 mm, respectively. As is clear from this graph, the uniformity of the ashing rate is best when the holes are distributed within the same circle with a diameter of 150 mm as the wafer, and when the holes are distributed over a wider range or a narrower range, both cases are observed. It can be seen that the uniformity has deteriorated.

[0025]

[Effect of the device]

 As described above, in the ashing device of the present invention, since the formation area of the holes of the partition wall is set corresponding to the sample, the present invention is excellent in that the sample can be uniformly ashed. It is effective.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration of an ashing device according to the present invention.

FIG. 2 is a graph showing the relationship between the distribution of holes in the partition wall and the resist removal rate (average value).

FIG. 3 is a schematic cross-sectional view showing the configuration of a conventional ashing device.

[Explanation of symbols]

 1 Reactor 2 Dielectric Line 3 Gas Supply Pipe 5 Waveguide 13 Partition Wall 14 Plasma Generation Chamber 15 Ashing Treatment Chamber 16 Mounting Stand 17 Holes S Sample

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // C23C 16/50 7325-4K

Claims (1)

Claims for utility model registration: 1. A waveguide for transmitting microwaves, a dielectric line connected to the waveguide, and a reactor arranged to face the dielectric line. Then, the inside of the reactor is arranged so as to be separated into a plasma generation chamber that generates plasma and an ashing processing chamber that includes a mounting table on which the ashing target is mounted.
In an ashing device having a partition wall provided with a plurality of holes for communicating the plasma generation chamber and the ashing processing chamber, a distribution area of the holes of the partition wall is substantially the same as the size of the ashing target. Ashing device.