JP3003219B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation technique used for manufacturing a semiconductor device and a semiconductor integrated circuit device.

[0002]

2. Description of the Related Art As a conventional ion implantation apparatus, Japanese Patent Application Laid-Open No. 58-87748 discloses a system in which Faraday cups are arranged in the X and Y axis directions to determine the center of a beam.

[0003]

However, although these devices can determine the center of the ion beam, they do not take care of monitoring and controlling the implantation angle.

Accordingly, it is an object of the present invention to monitor an actual ion implantation angle and to feed back an angle control system so that ion implantation can be performed at an accurate angle.

One object of the present invention is to enable real-time monitoring of an ion implantation angle in ion implantation.

An object of the present invention is to enable real-time change of an ion implantation angle in ion implantation.

One object of the present invention is to provide an LDD (Lightly Doped Dra) having a uniform implantation density.
in) To enable the structure.

An object of the present invention is to enable control of an ion implantation angle suitable for a high current ion implantation apparatus.

An object of the present invention is to enable an LDD process without using a sidewall.

[0010]

The following is a brief description of an outline of the present invention for achieving the above object.

That is, the current density of the ion beam emitted from the ion source near the sample stage position of the ion implantation apparatus is detected, and the angle data of the ion beam incident on the main surface of the semiconductor wafer on the sample stage is calculated. A semiconductor device, comprising: automatically adjusting an implantation angle of the ion beam based on the incident angle data; and implanting impurity ions into the semiconductor wafer at the adjusted implantation angle. It is a manufacturing method of.

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

The ion beam emitted from the ion source is captured by the angle monitoring Faraday cup to which the microelectrode is attached, so that a beam profile can be obtained. From this, a microcomputer connected to an ammeter is used to determine the center of the ion beam, and the position where the current value is the largest is determined as the beam center. The incident angle of the ion beam is calculated based on how much the center position of the beam deviates from the center position of the Faraday cup. By feeding this data back to the angle controller of the ion source or the angle controller of the platen (wafer stage), the ion implantation angle can be accurately controlled.

[0018]

Embodiments Hereinafter, specific embodiments will be described. The same reference numerals in these examples and drawings indicate that they have the same or similar functions. However, this does not apply particularly when a statement to the contrary is stated. In the present application, the term “semiconductor device” includes both a single transistor and an integrated circuit such as an IC unless otherwise specified.

In the description of the embodiments, a plurality of embodiments are described for the sake of convenience. However, each of the embodiments is not a separate one, and the other is mutually different, modified, or uses them. In a relationship of things.

(1) Embodiment 1 (Electromagnetic Deflection Type, Medium Current Type) FIG. 1 is a schematic plan sectional view of an entire ion implantation apparatus according to an embodiment of the present invention. In the figure, 1 is an ion source,
2 is an ion extraction unit, 3 is a mass analysis unit, 4 is a post-acceleration unit,
5 is a quadrupole lens for converging the ion beam, 6 is a Y deflection plate,
7 is an X deflecting plate, 8 is a beam shielding plate (or cutting mask) for shaping a beam to a required size, 9 is a Faraday cup, 10 is a wafer to be processed, 11 (or 17) is a platen, and 32 is an ion. It is an injection chamber.

FIG. 2 is a sectional view of a main part corresponding to FIG. In the figure, 1 is an ion source, 8 is a beam shielding plate (or cutting mask) for shaping a beam to a required size, 9 is a Faraday cup, 10 is a wafer to be processed, 12 is a bias ring, and 13 is a current. Total, 14
Is a microcomputer for measurement calculation, 15 is a platen angle control unit, 16 is an ion source angle control unit, 17 (or 11) is a platen, 18 is a microelectrode, 19 is a platen angle monitor, and 33 is the whole of 17 and 18. And an ion beam monitor or a beam current distribution detector.

The ion source 1 is, for example, a freeman (fr)
eeman) source to release the desired ions as needed. The mass analyzer 3 selects desired ions from the various ions emitted by the ion source by the action of a magnetic field. The post-accelerator 4 accelerates or decelerates the ions selected by the mass analyzer to a predetermined implantation energy. The converging lens 5 converges the ion beam passing through the post-acceleration tube 4 to an appropriate size by electrostatic action. Y
The deflecting plate 6 converts the ion beam into Y in a plane perpendicular to the beam.
Scan electrostatically in the direction. The X deflection plate 7 electrostatically scans the ion beam in the X direction in a plane perpendicular to the beam.
The beam shielding plate 8 is a shielding plate having an opening of a predetermined size, and cuts off unnecessary peripheral beams. The Faraday cup 9 monitors the amount of implanted ions by collecting the ions implanted into the cup-shaped collector electrode. The bias ring 12 is provided to reduce the influence of secondary electrons. The ammeter group 13 monitors the ion current flowing into each microelectrode 18. (Note that the monitoring of the postage of the ions implanted into the wafer 10 to be processed is performed by the usual Faraday cups 9 and 12 and the ammeter connected thereto.) The microcomputer 14 calculates the current distribution data from the ammeter group 13. The angle between the center line of the ion beam and the normal line on the main surface of the wafer to be processed, that is, the implantation angle is calculated, and based on the calculated angle, the platen angle controller 1
5. Operate the ion source angle controller 16 or the platen angle monitor 19 to control the implantation angle. The platen 17 holds the wafer 10 to be processed thereon as shown by a broken line in the figure. The microelectrode group 18 includes a large number of mutually insulated electrodes provided on the inner surface of the cylindrical hollow portion of the platen 17, and each electrode is connected to the ammeter group 13. The platen angle monitor 19 is a platen 17 for laser light.
The main surface of the platen 17 due to reflection by the back surface, that is,
The inclination of the main surface of the wafer is detected. The implantation chamber 32 accommodates a wafer to be processed therein and performs ion implantation.
It is kept in a high vacuum state of about 1.0 × 1.0 ⁻⁶ Torr or more.

Next, the operation of the operation will be described with reference to FIGS. Generally, the ion implantation process is performed by batch processing in which a wafer group including a plurality of cassettes is a unit batch. First, the first processing to be performed first
Is introduced into the injection chamber 32 through the load lock chamber. The introduced wafers are placed one by one on the platen 11 and subjected to ion implantation. When the processing of the first batch is completed, all wafers are taken out of the injection chamber via the load lock chamber. Next, when a second batch for performing a second process different from the above-mentioned process is loaded into the loader, the ion implanter may execute the batch from a wafer, a cassette, or an external computer system belonging to the second batch. Read the processing specification data of
If the preceding process is different, especially in the ion species, implantation energy, etc., the monitoring operation of the implantation angle is automatically executed. That is, as shown in FIG. 2, in a state where the wafer 10 is not mounted on the platen 17, implantation is performed under the same conditions as those to be executed, and the distribution of the ion beam current is measured by the beam current monitor 33. And the data is calculated by the internal computer 14 to calculate the driving angle. The internal computer 14 adjusts the direction of the platen 17 with the platen angle control unit 15 while optically detecting the direction of the platen 17 with the laser angle monitor based on the angle data. In this case, the direction of the ion source 1 may be adjusted. On the other hand, while such monitoring is being performed, the wafer cassette storing the wafers belonging to the second batch is evacuated to a high vacuum in the load lock chamber. When the angle monitoring is completed as described above, the wafer belonging to the second batch is introduced into the injection chamber 32 from the load lock chamber. The wafers introduced into the implantation chamber 32 are placed one by one on the platen 17 as before, and ion implantation is performed.

(2) Embodiment 2 (Electromagnetic Deflection Type, Medium Current Type) FIGS. 3A to 3C are cross-sectional views of a main part of an ion implantation apparatus according to an embodiment of the present invention. In the following embodiments, since the overall view is the same or almost the same as that of FIG. 1, the description will be omitted unless particularly necessary. 3a to 3c, 1 is an ion source, 8 is a beam shielding plate (or a cutting mask) for shaping a beam to a required size, 9 is a Faraday cup, 10 is a wafer to be processed, 11 is a platen, 12 Is a bias ring, 13 is an ammeter, 14 is a microcomputer for measurement calculation, 15 is a platen angle controller, 16 is an ion source angle controller, 18 is a microelectrode, 19 is a platen angle monitor, and 20 is provided in a Faraday cup. The movable measurement unit, that is, the flag.

That is, the flag 20 which forms a part of the Faraday cup 9 retreats to the side of the ion beam path at the time of normal ion implantation as shown in FIG. 3A, and rotates as shown in FIG. 3C at the time of monitoring the implantation angle. FIG. 3b
The driving angle is monitored in the state of.

The operation of this apparatus is substantially the same as that of the first embodiment, and will not be repeated here. The feature of this apparatus is that the flag protrudes into the path of the ion beam when the angle monitor is used. Therefore, in this apparatus, the platen 11
The structure becomes simple.

(3) Embodiment 3 (Electromagnetic Deflection Type, Medium Current Type) FIG. 4 is a sectional view of a main part of an ion implantation apparatus according to an embodiment of the present invention. In the figure, 1 is an ion source, 8 is a beam shielding plate (or cutting mask) for shaping a beam to a required size, 9 is a Faraday cup, 1
0 is a wafer to be processed, 11 is a platen, 12 is a bias ring, 13 is an ammeter, 14 is a microcomputer for measurement calculation, 15 is a platen angle controller, 16 is an ion source angle controller, 18 is a microelectrode, and 19 is a microelectrode. A platen angle monitor 33 is an ion beam monitor or a beam current distribution detector showing the whole of the above 8 and 18.

FIG. 12 is a front view of the arrangement of the current distribution detector of FIG. 4 as viewed from the ion source side. In the figure, reference numerals 33a to 33d denote ion beam monitors or beam current distribution detectors, respectively, and 34 denotes a cross section of a main region of the implanted ion beam. Next, the operation of the operation will be described with reference to FIGS. In this apparatus, loading and unloading of a wafer to be processed are almost the same as those in the first embodiment, but the angle monitoring operation is different. That is, in this apparatus, the ion implantation angle of the beam is calculated by the same operation as described above by detecting the distribution of the ion current around the implanted ion beam in real time while performing the ion implantation into the wafer, and the data is obtained. The ion implantation angle is changed in real time by automatically adjusting the direction of the platen 11 or the ion source 1 based on the angle.

As described above, high-precision ion implantation can be realized by monitoring the implantation angle regularly or constantly during ion implantation and correcting the implantation angle based on the monitoring. Further, according to the present apparatus, the implantation angle can be changed continuously (or intermittently) while monitoring the implantation angle continuously (or intermittently) during ion implantation.

(4) Fourth Embodiment (Mechanical Rotation and Electromagnetic Deflection Type, Medium Current and Large Current Type) FIG. 5 is a schematic cross-sectional view of the entire top surface of an ion implantation apparatus according to one embodiment of the present invention. Note that a cross-sectional view of a main part corresponding to FIG. 5 is substantially the same as any one of FIG. 7, FIG. 8a to FIG. 8c, and FIG. In the figure, 1 is an ion source, 2 is an ion extraction unit, 3 is a mass analysis unit, 9 is a Faraday cup, 10 is a wafer to be processed, 21 is an X scan magnet, 22 is an angle correction magnet, and 23 is a rotating disk (wafer). Holder or wafer stage), a 24 disk rotation drive control unit.

Here, the X scan magnet 21 scans the ion beam in the X direction in a plane perpendicular to the ion beam by a magnetic field. The rotating disk 24 holds a plurality of wafers to be processed and performs high-speed rotation as a Y scan.

The operation of the present apparatus is almost the same as that of FIGS. 7, 8a to 8c, and 9 and will be described in those embodiments. (5) Fifth Embodiment (Mechanical Rotary Type, High Current Type) FIG. 6 is a schematic top schematic sectional view of an entire ion implantation apparatus according to an embodiment of the present invention. In the drawing, 1 is an ion source, 2 is an ion extraction unit, 3 is a mass analysis unit, 4 is a post-stage acceleration unit, 9 is a Faraday cup, 10 is a wafer to be processed, 23
a is a rotating disk (wafer holder or wafer stage), 25 is a mass analysis and beam shaping slit, 2
Reference numeral 6 denotes a disk rotation horizontal drive unit, and reference numeral 32 denotes an injection chamber.

FIG. 7 is a sectional view of a main part corresponding to FIG. In the figure, 1 is an ion source, 8 is a beam shielding plate for shaping a beam to a required size, 9 is a Faraday cup, 10 is a wafer to be processed, 12 is a bias ring, 13 is an ammeter, and 14 is a measurement. An arithmetic microcomputer, 16 is an ion source angle control unit, 18 is a microelectrode, 19 is a platen angle monitor, 23a is a rotating disk (wafer holder or wafer stage), and 26 is a disk rotation horizontal drive unit.

Here, the rotary moving disk 23a holds a plurality of wafers and performs high-speed rotation and parallel movement so as to correspond to XY scanning on the inner surface perpendicular to the ion beam. The disk rotation horizontal drive unit 26 performs rotation driving and horizontal driving of the disk 23.

Next, the operation of the operation will be described with reference to FIGS. In general, a large current type apparatus does not operate the ion beam, but scans the entire surface of each wafer to be processed by rotating and rotating the rotating stage on which a large number of wafers are placed. Like that.
Therefore, a plurality of wafers belonging to the batch introduced into the implantation chamber 32 are simultaneously placed on the wafer stage 23a, and ion implantation is performed at the same time. in this case,
The monitoring is automatically performed when a specific driving specification is changed, as in the first embodiment. At this time, the distribution is measured in a state where the wafer to be processed is not yet mounted in the arrangement of FIG. 7 as shown in the first embodiment.

The details of the high-current ion implantation apparatus of this embodiment and the following embodiments are described in Japanese Patent Application No. 2-6 / 1990.
No. 7014, the description of the present application is taken accordingly.

(6) Embodiment 6 (Mechanical rotation type, large current type) FIGS. 8A to 8C are cross-sectional views of a main part of an ion implantation apparatus according to an embodiment of the present invention. In addition, FIG.
Corresponds. In the figure, 1 is an ion source, 8 is a beam shielding plate for shaping a beam to a required size, 8
Is a Faraday cup, 10 is a wafer to be processed, 12 is a bias ring, 13 is an ammeter, 14 is a microcomputer for measurement calculation, 16 is an ion source angle controller, 18 is a microelectrode, 19 is a platen angle monitor, and 20 is Faraday. A movable measuring unit or flag provided in the cup,
Reference numeral 23a denotes a rotating disk (wafer holder or wafer stage), and reference numeral 26 denotes a disk rotation horizontal drive unit.

Next, the operation will be described with reference to FIGS. 8A to 8C. The operation of the ion beam implantation angle monitor is the same as that of FIGS. 3A to 3C and will not be repeated here. Further, the loading and unloading of the rotating disk 23a and the wafer to be processed, and the ion implantation process are almost the same as those in FIG. 6, and therefore will not be repeated.

In this apparatus, since a complicated mechanism such as a beam current detector is not provided on a rotating disk which performs a complicated operation, the structure of the rotating disk 23a is relatively simplified. Can be.

(7) Embodiment 7 (Mechanical rotation type, large current type) FIG. 9 is a sectional view of a main part of an ion implantation apparatus according to an embodiment of the present invention. FIG. 6 corresponds to the overall diagram. In the figure, 1 is an ion source, 8 is a beam shielding plate for shaping a beam to a required size, 9 is a Faraday cup, 10 is a wafer to be processed, 11 is a platen, 12 is a bias ring, and 13 is an ammeter. , 14 is a microcomputer for measurement calculation, 16 is an ion source angle controller, 18
Is a microelectrode, 19 is an platen angle monitor, 23a is a rotating disk (wafer holder or wafer stage), and 26 is a disk rotation horizontal drive unit.

Next, the operation of the operation will be described with reference to FIG. The operation of the ion beam implantation angle monitor is the same as that of FIG. 4 and will not be repeated here. Further, the loading and unloading of the rotating disk 23a and the wafer to be processed, and the ion implantation process are almost the same as those in FIG. 6, and therefore will not be repeated.

In the present apparatus, since the driving angle can be monitored in real time, it is possible to change the driving angle in real time by moving the rotary axis to a smaller size while driving the rotary moving disk in rotational translation.

(8) Eighth Embodiment (Manufacturing Process 1 / Sidewall Process) FIGS. 10A and 10B show a method of manufacturing a semiconductor device according to an embodiment of the present invention. In the figure, 27 is a gate electrode, 28 is an implanted ion beam, 29 is a low concentration source / drain layer, 30 insulating sidewalls, and 31 a high concentration source / drain layer.

The gate electrode 27 is formed of, for example, a polycide film and has a width of about 1.3 μm and a thickness of about 350 nm. The sidewall 30 is formed by anisotropically etching a silicon dioxide film by CVD, and its lateral direction is formed. The field is about 0.2 μm. The low-concentration drain layer 29 has a depth of about 0.2 μm (monovalent ion of phosphorus, 50 KeV,
1.0 × 10 ¹³ / cm ² , implantation angle 0 °, that is, vertical implantation), and the high concentration source / drain layer 31 has a depth of 0.1 × 10 ¹³ / cm ² .
About 25 μm (As monovalent ion, 80 KeV, 5.0
× 10 ¹⁵ / cm ² , a driving angle of 0 °, that is, vertical driving). The thickness of the gate oxide film is about 25 nm.

According to the present process, the ions can be implanted vertically in a precise manner, so that an undesired offset between the gate and the source / drain can be prevented from occurring even in the sidewall process or the like.

This process is performed by the apparatus according to any of the above embodiments.

(9) Ninth Embodiment (Manufacturing Process 2 / Non-Sidewall Process) FIGS. 11A and 11B show a method of manufacturing a semiconductor device according to an embodiment of the present invention. In the figure, 27 is a gate electrode, 28 is an implanted ion beam, 29 is a low concentration source / drain layer, and 31 is a high concentration source / drain layer.

The gate electrode 27 is formed of, for example, a polycide film and has a width of about 1.3 μm and a thickness of about 350 nm. The low-concentration source / drain layer 29 has a depth of about 0.2 μm (monovalent ion of phosphorus, 70 KeV, 1.0 × 10 ¹³ /
cm ² , implantation angle 45 °), and the high concentration source / drain layer 31 has a depth of about 0.25 μm (As monovalent ion, 8
0 KeV, 5.0 × 10 ¹⁵ / cm ² , driving angle 0 °
That is, vertical driving). The thickness of the gate oxide film is about 25 nm.

According to this process, a low-concentration layer having an LDD structure can be formed with high accuracy by a self-alignment process without using a sidewall or the like. Further, according to the present process, the CVD for forming the sidewall
A self-aligned doping process that is not affected by process variations of the insulating film can be provided.

It is needless to say that the apparatus of any of the above embodiments can be applied when performing the processes of the above embodiments. This process is performed by the apparatus according to any of the above embodiments.

[0051]

The effects of those obtained by the representative inventions among the inventions disclosed in the present application are described as follows.

That is, by detecting the current distribution of the implanted ion beam with a Faraday cup having a large number of microelectrodes arranged approximately two-dimensionally on a two-dimensional surface of a plane or three-dimensional surface, the accurate incidence of the incident beam is achieved. The angle is calculated, and the actual driving angle can be controlled with high accuracy based on the calculated angle. Specifically, it is possible to precisely control the driving angle error to about ± 0.5 °.

Although the technical field, ie, MOSIC, which has been the background of the present invention has been described above, it is needless to say that the present invention is not limited to this and can be variously modified without departing from the gist of the present invention. . For example, the present invention can be applied to a bipolar IC or a hybrid IC thereof.

[Brief description of the drawings]

FIG. 1 is a schematic plan cross-sectional view of an entire ion implantation apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part corresponding to FIG.

FIG. 3a is a sectional view of a main part of an ion implantation apparatus according to one embodiment of the present invention.

FIG. 3b is a sectional view of a main part of the ion implantation apparatus according to one embodiment of the present invention.

FIG. 3c is a sectional view of a main part of the ion implantation apparatus according to one embodiment of the present invention.

FIG. 4 is a sectional view of a main part of the ion implantation apparatus according to one embodiment of the present invention.

FIG. 5 is a schematic top cross-sectional view of an entire ion implantation apparatus according to one embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of the entire top surface of the ion implantation apparatus according to one embodiment of the present invention.

FIG. 7 is a sectional view of a main part corresponding to FIG. 6;

FIG. 8A is a sectional view of a main part of an ion implantation apparatus according to one embodiment of the present invention.

FIG. 8B is a sectional view of a main part of the ion implantation apparatus according to one embodiment of the present invention.

FIG. 8c is a sectional view of a main part of the ion implantation apparatus according to one embodiment of the present invention.

FIG. 9 is a sectional view of a main part of an ion implantation apparatus according to one embodiment of the present invention.

FIGS. 10A and 10B show a method of manufacturing a semiconductor device according to an embodiment of the present invention.

FIGS. 11A and 11B show a method of manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 12 is a front view of an arrangement of ion beam monitors provided at the cutting masks of FIGS. 5 and 9 as viewed from each ion source side.

[Description of Signs] 1 ... Ion source, 2 ... Ion extraction unit, 3 ... Mass analysis unit, 4 ... Post-acceleration unit, 5 ... Quadrupole lens for ion beam convergence, 6 ... Y deflection plate, 7 ... X deflection plate , 8 ... Beam shielding plate for shaping beam to required size, 9 ... Faraday cup, 10 ... Unprocessed wafer, 11 ... Platen, 12
... Bias ring, 13 ... Ammeter, 14 ... Microcomputer for measurement calculation, 15 ... Platen angle controller, 16
... Ion source angle control unit, 17 ... Platen, 18 ... Microelectrode, 19 ... Platen angle monitor, 20 ... Movable measurement unit or flag provided in Faraday cup, 2
DESCRIPTION OF SYMBOLS 1 ... X scan magnet, 22 ... Angle correction magnet, 23 ... Rotating disk (wafer holder or wafer stage), 23a ... Rotating moving disk (wafer holder or wafer stage), 24 ... Disk rotation drive control part, 25 ... Mass analysis and Beam shaping slit, 26 ...
Disk rotation horizontal drive unit, 27 gate electrode, 28 implanted ion beam, 29 low concentration source / drain layer,
Reference numeral 30 denotes an insulating sidewall, 31 denotes a high-concentration source / drain layer, 32 denotes an ion implantation chamber, 33 denotes an ion beam monitor, and 34 denotes a main region of an ion beam.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI H01L 21/265 V (72) Inventor Masashi 5-20-1, Josuihoncho, Kodaira-shi, Tokyo Inside the Musashi Plant of Hitachi, Ltd. (56) References JP-A-58-87748 (JP, A) JP-A-63-254651 (JP, A) JP-A-63-140524 (JP, A) JP-A-2-162641 (JP, A) ( 58) Surveyed field (Int.Cl. ⁷ , DB name) H01L 21/265 H01J 37/317

Claims (4)

(57) [Claims] 1. A method of manufacturing a semiconductor device, comprising the step of irradiating an ion beam emitted from an ion source onto a semiconductor wafer at a predetermined implantation angle to implant an impurity, wherein the impurity is implanted into the semiconductor wafer. While detecting the current distribution of the ion beam, calculate the angle of incidence of the ion beam on the main surface of the semiconductor wafer, if the calculated angle of incidence is different from the predetermined implantation angle, A method for manufacturing a semiconductor device, comprising: correcting an implantation angle. 2. The method according to claim 1, wherein the detection of the current density of the ion beam is performed using a Faraday cup having a plurality of collector electrodes. 3. The apparatus according to claim 1, wherein the adjustment of the driving angle is performed by changing an angle of the sample stage.
The manufacturing method of the semiconductor device described in the above. 4. A step of placing a semiconductor wafer on which a gate electrode is formed on a sample stage of an ion implantation apparatus, and obtaining an angle of incidence of an ion beam during ion implantation into the semiconductor wafer, based on the angle. Automatically adjusting the implantation angle of the ion beam by using the method.