JPH0267725A - Heat-treating device for formation of silicified contact of semiconductor device - Google Patents

Abstract

PURPOSE:To form a silicified contact with good reproducibility by a method wherein wafers are heated in a furnace, which is controlled in the temperature in its interior and in which the air is not mixed, of an indirectly heating system one sheet by one sheet for a prescribed time. CONSTITUTION:The interior of a heat-treating furnace main body 41 is set in an N2-containing atmosphere, a heater conductor 43 is provided on the outside of the upper part of a vertical quartz tube 44, wafers are heated in an indirectly heating manner from the periphery of the upper part and the temperature in the furnace is controlled by a thermocouple 47 and a heater power supply 48. Carriers 62 and 63 for housing pre-treatment and treatment finished wafers are housed in a wafer carrier 60 in a vertically movable state and the interior of the carrier 60 is set in an N2-containing atmosphere. A horizontal transfer mechanism 70 is constituted into a structure, wherein an extraction rod 74 with a wafer pan 73 fixed thereon is supported in a cylindrical body 75, and a vertical transfer mechanism 71 is constituted into a structure, wherein an extraction rod 80 with a wafer supporting member 79 fixed thereon is provided in a cylindrical body 81. The rod 41 is moved moved in a direction X2 and the pan 73 supports one sheet of a wafer and reaches in a transfer part 72. Then, the rod 80 is moved in a direction Y1, the wafer is transferred from the member 79, reaches a wafer carrying-in part 45 and stays for a prescribed time. During this, a contact window part formed in a titanium film is transformed into a silicide and the wafer is extracted outside of the furnace main body 41 and is returned in the wafer carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat treatment apparatus for forming silicided contacts in semiconductor devices.

FIGS. 17A to 17C show the structure in the step of forming a silicide contact in the manufacturing process of an MO8 type semiconductor device.

In each figure, 1 is a p-type silicon substrate (wafer), 2 is a field S i 02 B'Jr, 3a, 3b are n+ diffusion layers, 4a, 4b are n- diffusion layers, 5 is a gate Sio2 layer, 6
is an n-type poly-Si layer, 7 is a tungsten silicide layer, and 8 is a tungsten silicide layer.
9 is a SiO2 layer, 9a and gb are sidewall 3i02 layers, and 10 is a PSG film.

Figure (A) shows the state before heat treatment. 11 is a titanium film, which is formed over the entire surface. This state is heat treated to form a silicided contact.

The figure (B) shows the state after heat treatment.

Due to the heat treatment, the silicon of the silicon base a'11 invades into the titanium film 11, and the contact window 1 of the titanium film 11 is
The portions inside 2a and 12b are silicided to form a titanium silicide contact F5ff13a.

13b is formed.

After that, the titanium film 11 is connected to the titanium silicide contact l113a by HO-NH40H.

13b is left, and an AfJ film is formed and etched to form Aρ wirings 14a, 14 as shown in FIG.
b are titanium silicide contact layers 13a and 13b, respectively.
and the n+ diffusion layer 4a.

It is formed without penetrating into 4b and with reduced contact resistance.

Here, if titanium remains between the A1 wirings 14a, 14b and the PSG film 10, it will react excessively with the silicon of the substrate 1 from the contact window part during the repeated heat treatment and become silicided, resulting in a defect. . Therefore, it is necessary to leave the necessary amount of titanium hanging only in the contact windows 12a and 12b.

If the heat treatment becomes excessive, the contact window 12a.

If the silicided portion extends to the outside of the contact window 12b and the heat treatment is insufficient, the contact window 12
Silicidation of portions a and 12b becomes insufficient.

Therefore, a well-controlled heat treatment is required so that the titanium film only in the contact windows 12a and 12b is completely silicided.

[Conventional technology]

FIGS. 18(A) and 18(B) show a conventional heat treatment apparatus 20 for forming silicided contacts. This heat treatment apparatus 20 is of a direct heating type, and halogen lamps 21 and 22 are heat sources.

23 is a flat chamber made of quartz, and 24 is a gate valve. Halogen lamps 21 and 22 are provided on the upper and lower surfaces of the chamber 23.

The wafers 25 in the state shown in FIG. 17(A) are supported one by one on a quartz support stand 26 and carried into the chamber 23 through the gate valve 24.

Atmospheric gas is continuously and sufficiently supplied into the chamber 23 from the gas supply 27, and the air inside the narrow chamber 23 is replaced by the atmospheric gas. 28 is a gas outlet.

The wafer 25 is heated by absorbing infrared rays from the halogen lamps 21 and 22, and the titanium film is silicided.

[Problem to be solved by the invention]

Each wafer 25 has a different history, and the type, thickness, and area of the deposited film on the wafer differ. For this reason, 1. Each wafer 25 has a different degree of absorption of infrared rays, and the halogen lamp 21.
Even if the power of the wafer 22 is constant, the heating temperature will differ for each wafer 25.

Furthermore, it is inherently difficult to accurately measure the temperature of a wafer during heat treatment, and it is difficult to control the heating temperature based on the actual temperature of the wafer.

For this reason, it has been difficult to form silicided contacts with good reproducibility.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat treatment apparatus for forming silicided contacts of a semiconductor device, which can form silicided contacts with good reproducibility.

[Means to solve the problem]

FIG. 1 is a diagram showing the basic structure of a heat treatment apparatus 30 for forming silicided contacts in a semiconductor device according to the present invention.

31 is an indirect heating type heat treatment furnace body.

32 is means for controlling the temperature of the heat treatment furnace body.

Reference numeral 33 denotes means for keeping air out of the heat treatment furnace body 31.

34 is a wafer carrier that stores a plurality of wafers.

35 carries the wafers one by one into the heat treatment furnace main body 31 from the wafer carrier 34, and after keeping them there for a predetermined time in seconds, carries them out from the heat treatment furnace main body 31 and transfers them to the wafer carrier 34.
- It is a wafer-by-wafer transport means.

[Effect]

The wafers are heated one by one in the heat treatment furnace main body 31, which has an air-free atmosphere and whose temperature is controlled, indirectly, that is, by thermal conduction.

Therefore, each wafer is heated to a predetermined temperature without variation, almost unaffected by the history of the wafer.

As a result, silicidated contacts are formed uniformly and reproducibly on each wafer.

(Embodiment) FIG. 2 shows a small scale heat treatment apparatus 40 for forming a silicided contact of a semiconductor device, which is an embodiment of the present invention.

41 is a vertical heat treatment furnace body, and a cylindrical body 42 made of a heat insulating material
A heater wire 43 is provided on the inner circumferential surface of the tube and is fitted around the upper end of a vertical quartz tube 44.

This heat treatment furnace 41 is of an indirect heating type in which a heater wire 43 heats the atmosphere inside a quartz tube 44 and the wafer is heated by heat conduction from the surroundings.

This heat treatment furnace body 41 is of an indirect heating type, the temperature inside the furnace body 41 is controlled as explained below, and furthermore, it is a single wafer type in which wafers are brought in one by one. , the wafer is heated to a predetermined temperature regardless of its history.

Reference numeral 45 denotes a wafer loading section into which wafers are loaded for heat treatment, and is located approximately at the center of the vertically long furnace body 41.

46 is a temperature control device, which includes a thermocouple 47 that measures the temperature at three locations inside the furnace body 41, at the center and below L, and a heater wire 43.
The configuration includes a power supply 48 that supplies current to the thermocouple 47, and a control circuit 49 that controls the 'Fi source 48 in accordance with the output of the thermocouple 47.

This device 46 controls the temperature of the atmosphere within the furnace body 41 to a predetermined temperature (650° C.).

50 is a heat radiation prevention plate made of opaque quartz.

51 is an exhaust pipe at the upper end of the quartz tube 44; 52 is an exhaust pump;
53 is an N2 gas inlet at the lower end of the quartz tube 44.

These form the means 33 mentioned above.

By driving the exhaust pump 52, the air inside the furnace body 41 is evacuated and the inside of the furnace body 41 is brought into a vacuum state, and N2 gas is introduced to create a N2 gas atmosphere in the furnace body 41.

A wafer carrier 60 houses a carrier 62 for storing a large number of unprocessed wafers 61 in a stacked state, and a carrier 63 for storing processed wafers.

An elevator 64 raises and lowers the carriers 62 and 63, and is driven by a motor 65.

The wafer carrier 60 has an airtight structure, and the exhaust pump 66
N2 gas is introduced from the N2 gas inlet 67 to create an N2 gas atmosphere inside.

Reference numeral 70 denotes a horizontal conveyance mechanism, and numeral 71 denotes a vertical conveyance mechanism, which constitute the above-mentioned wafer-by-wafer conveyance means 35, thereby performing single-wafer processing.

72 is a transfer section.

In the horizontal transfer mechanism 70, a pull-out rod 74 having a wafer holder 73 fixed to the tip thereof is movably supported in a cylinder 75, and the pull-out rod 74 is coupled from the outside of the cylinder 75 by a magnetic coupling 76. It is the composition.

The pull-out rod 74 is in a state of being moved in the x1 direction of the arrow, and the tray 73 is stored in the storage section 77.

Reference numeral 78 indicates an axial alignment portion of the pull-out rod 74.

With the above configuration, the horizontal transport mechanism 70 does not impair the airtightness of the wafer carrier 60.

The vertical transport mechanism 71 includes a pull-out rod 80 having a wafer support member 79 fixed to its upper end and is movably provided in a cylinder 81.
The pull-out rod 80 is connected to the outside of the cylindrical body 81 by a magnetic coupling 82.

The pull-out rod 80 is moving in the direction of arrow Y2, and the wafer support member 79 is located in the transfer section 72.

Reference numeral 83 denotes an axial alignment portion of the pull-out rod 80.

With the above configuration, the vertical conveyance mechanism 71 does not impair the airtightness of the furnace body 41.

A gate valve 84 is provided between the wafer carrier 60 and the transfer section 72.

Next, the operation of the heat treatment furnace apparatus 40 having the above configuration will be explained.

FIG. 3 shows the steps of the heat treatment operation.

FIGS. 4 to 13 each show the state at each step.

First, the state shown in FIG. 2 is established. The inside of the heat treatment furnace main body 41 is kept at a steady state of 650° C. and has an N2 gas atmosphere. Inside the wafer carrier 60 is a titanium film with a thickness of 500o-1! An unprocessed wafer 61 on which <FIG. 17<A) indicated by reference numeral 11 in FIG. Gate valve 84 is open.

A case is shown in which the processing of N wafers has been completed and the (N+1)th wafer is to be processed.

FIG. 4 shows a wafer support step 90.

By moving the magnetic coupling 76, the pull-out rod 74 is moved in the x2 direction of the arrow, and the tray 73 of the wafer receiver supports the N+1th wafer 61N+1.

FIG. 5 shows a horizontal wafer transfer step 91 to the transfer section.

The pull-out rod 74 is placed in the direction of arrow x2 via the magnetic coupling 76, and the wafer 61N+1 is transported in the direction of arrow x2 while the wafer receiver is supported by the tray 73, passes through the gate valve 84, and is transferred. It reaches inside the changing section 72.

FIG. 6 shows a transfer step 92.

The pull-out rod 80 is moved in the direction of arrow Y1 via the magnetic coupling 82, the seven support members push up the wafer 61, and the wafer 61N+1 is transferred from the support member 79 from the receiving tray 73.

As shown in FIG. 7, the wafer tray 73 has three fingers 73.
The seven wafer support members have three protrusions 79b and 79 on a disk 79a.
c and 79d are protruding shapes. The fingers 73a to 3C and the protrusions 79b to 79d have the positional relationship shown in the figure.

As a result, the wafer 61N+1 can be transferred from the wafer tray 73 to the wafer support member 79 without any trouble.

FIG. 8 shows the tray return process 93.

Through the magnetic coupling 76, the tray 73 is moved in the direction of arrow x1 and returned into the storage section 77.

FIG. 9 shows a vertical conveyance/heat treatment step 94.

The pull-out rod 80 is moved in the direction of arrow Y1 via the magnetic coupling 82, and the wafer 61 is removed.

The quartz tube 44 is supported horizontally on the support member 79.
The wafer is transported vertically in the direction of arrow Y1, and reaches the wafer loading section 45 in the furnace main body 41.

The wafer 61N+1 remains here for a predetermined time (approximately 60 seconds), and is then pulled out of the furnace main body 41.

While the wafer 61N+1 remains here, it is heated from the surroundings by thermal conduction, and the contact window portion of the titanium film is silicided.

Here, the temperature inside the furnace body 41 is controlled to a predetermined temperature, the heating is indirect heating by heat conduction, and the staying time is set to be one predetermined period.

Therefore, each wafer is heated to a predetermined temperature with high accuracy without being influenced by the history of the wafer.

Further, since the number of wafers carried into the furnace body 41 is one, the heating is rapid and the time the wafer remains in the furnace body 41 is short. Also, when the material is removed from the furnace as described below, it cools down quickly. Therefore, non-uniformity in temperature within the wafer during heating and cooling is eliminated.

As a result, the portions of the titanium film on the wafer facing each contact window are uniformly silinized in an ideal state.

In FIG. 3, 90 to 94 are the wafer loading process.

FIG. 10 shows the vertical conveyance step 95 to the transfer section.

The pull-out rod 80 moves in the direction of arrow Y2 via the magnetic coupling 82, and the processed wafer 61ΔN+1 is pulled out into the furnace body 41 while being supported by the support member 79, and reaches the transfer section 72.

When the wafer 61AN+1 is handled in the furnace main body 41, it is rapidly cooled because it is a single wafer.

Further, at this time, the elevator 65 is driven by the motor 65, and the carrier 63 is adjusted to a height position where the wafer 61 AN, 1 can be received.

FIG. 11 shows a transfer preparation step 96.

The tray 73 is moved in the direction of the arrow
, and enters between the wafer 61AN+1 and the support member 79.

FIG. 12 shows a step 97 of transferring the tray to the tray.

The support member 79 is further moved down, the holder of the wafer 61AN+1 is supported on the tray 73, and the holder is transferred to the tray 73.

FIG. 13 shows the horizontal transfer step 98 to the carrier.

The tray 73 moves in the direction of the arrow x1, and the wafer 61AN+
1 is conveyed horizontally, reaches the carrier 60, and is stored in the carrier 63.

The tray 73 moves further and returns to the storage section 77.

This completes the heat treatment of wafer 6114+1.

Subsequently, the elevator 64 is moved and the next wafer is heat-treated in the same manner as above.

In FIG. 3, 95 to 98 are the wafer unloading steps.

As can be seen from the above, the wafer is carried into the furnace by vertically transporting the wafer. If the transport distance in the horizontal direction is increased in the above-mentioned apparatus, a problem arises in that the pull-out rod is bent, making it difficult to obtain a long stroke.However, in this embodiment, since the transport distance is vertical, the transport distance can be increased.

Therefore, the transfer section 72 can be disposed at a location remote from the furnace body 41, and the wafer is removed from the furnace body 41 and quickly transferred to a position sufficiently distant from this, and cooling is performed rapidly.

FIG. 14 shows a heat treatment apparatus 100 according to another embodiment of the present invention.

The difference from the heat treatment apparatus 40 in FIG. 2 is that the wafer is heat treated in a vertical position. Components in FIG. 14 that correspond to those shown in FIG. 2 are designated by the same reference numerals, and their explanations will be omitted.

Reference numeral 101 denotes a wafer posture changing mechanism, which is provided within the transfer section 72. In this mechanism 101, as shown in FIG.
The structure is rotatable between a horizontal position and a vertical position.

The support plate 103 is initially in a horizontal position, and the receiver relatively enters under the wafer 61N+1 that has been placed on the tray 73A and transported (see FIG. 15).

In this state, the support plate 103 rotates in the direction of the arrow to a vertical position, and the wafer 61N+1 is locked by the locking claw 102 and supported by the support plate 103 to be in a vertical position.

A two-pronged locking pawl 105 is provided at the upper end of the pull-out rod 80.

When the pull-out rod 80 is moved in the direction of arrow Y1, the locking claw 1
05 locks the vertical wafer 61N+1 and is transferred in the direction of arrow Y1 while maintaining the vertical posture, carried into the furnace main body 41, and heat-treated in this posture.

Alternatively, the horizontal conveyance may be performed by a conveyance mechanism such as a belt.

Further, a horizontal furnace structure in which the heat treatment furnace body is arranged horizontally can also be used.

〔Effect of the invention〕

As explained above, according to the present invention, each wafer is heated one by one in an indirect heating type furnace main body in which the temperature inside the furnace is controlled. Regardless of its history, it can be heated accurately and in a short time, and silicided contacts can be formed with good reproducibility.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the basic configuration of a heat treatment apparatus for forming silicided contacts according to the present invention, FIG. 2 is a diagram showing a heat treatment apparatus according to an embodiment of the present invention, and FIG. 3 is a diagram showing the heat treatment apparatus of FIG. Figure 4 is a diagram showing the state during the wafer support process. Figure 5 is a diagram showing the state during the horizontal transfer process of the wafer to the transfer section. Figure 6 is the diagram showing the state during the wafer support member. Figure 7 shows the state of the wafer receiver during the transfer process, Figure 7 shows the state of the wafer receiver as viewed from the -■ direction in Figure 6, showing the tray and the wafer support member, and Figure 8 shows the state of the receiver during the tray return process. Figure 9 is a diagram showing the state during the wafer vertical transfer and heat treatment process, Figure 10 is a diagram showing the state during the vertical wafer transfer process to the wafer transfer section, and Figure 11 is the wafer preparation for transfer. Figure 12 is a diagram showing the state during the process of transferring the wafer to the tray; Figure 13 is a diagram showing the state during the horizontal transfer process of the wafer to the carrier; Figure 14 15 is a diagram showing a heat treatment apparatus according to another embodiment of the present invention, FIG. 15 is a diagram showing a state before operation of the wafer attitude changing mechanism in the transfer section in FIG. 14, and FIG. Figures 17(A), 17(B), and 17(C) are diagrams illustrating the formation of silicided contacts by heat treatment, and Figures 18(A) and 18(B) are diagrams showing the state after operation, respectively. FIG. 1 is a cross-sectional plan view and a vertical cross-sectional elevation view showing a heat treatment apparatus. In the figure, 11 is a titanium film, 12a and 12b are contact windows, 13a and 13b are titanium silicide contact layers, and 30
31 is an indirect heat treatment furnace body; 32 is a temperature control means; 33 is a means for forming an air-free state; 34 is a wafer carrier; 35 is a means for transporting each wafer; 40 is a heat treatment unit 1A for forming silicide contacts of semiconductor devices, 41 is a heat treatment furnace main body, 42 is a cylinder, 43 is a heater wire, 44 is a quartz tube, 45 is a wafer loading section, 46 is a temperature control device, 47 is a thermoelectric Pair, 48 is a power supply, 49 is a control circuit, 51 is an exhaust port, 52 is an exhaust pump, 53 is an N2 gas inlet, 60 is a wafer carrier, 61.61. + is a wafer, 61 A is a processed wafer, 62 is an unprocessed wafer storage carrier, 63 is a processed wafer storage carrier, 70 is a horizontal transport mechanism, 71 is a vertical transport mechanism, 72 is a transfer section, 73 is a The wafer receiver is a tray, 79 is a wafer support member, 90 is a wafer support process, 91 is a horizontal transfer process to the transfer section, 92 is a transfer process to the support member, 93 is a tray return process, 94 is a vertical transfer process・Heat treatment process; 95 is a vertical transfer process to the transfer section; 96 is a transfer preparation process; 97 is a transfer process for the receiver to the tray; 98 is a horizontal carrier transfer process; 100 is a heat treatment device; 101 is the wafer posture The conversion mechanism is shown. 30 Heat treatment equipment Diagram explaining the process during heat treatment Diagram Diagram Diagram Diagram depicting the state of the support process Diagram showing the state during the transfer process to the support member Diagram 6 Diagram showing the state during the process of transferring to the support member Diagram 6 Figure 7 shows the state during the vertical conveyance/co-processing process. Figure 9 shows the state of the receiver during the plate return process. Figure 8 shows the state during the vertical conveyance process to the transfer section. Fig. 10 shows the state during the transfer preparation process Fig. 13 shows the state during the horizontal transfer process to the carrier Fig. 13 shows the state during the transfer process to the tray Remains of another embodiment of the present invention Fig. 14 shows the processing device. Fig. 15 shows the state of the wafer attitude changing mechanism before operation. Fig. 16 shows the state after the wafer attitude changing mechanism operates. Fig. 16 explains the formation of unresided contacts. Figure 17

Claims (1)

[Scope of Claims] A heat treatment apparatus that heat-treats a wafer (61) during the manufacturing process of a semiconductor device to silicide contacts, comprising: an indirect heat treatment furnace body (31, 41); and a temperature inside the heat treatment furnace. means (32, 46) for controlling the heat treatment furnace; means (33, 52, 53) for creating an air-free state in the heat treatment furnace; and a wafer carrier (34, 60) for accommodating the wafer. and wafer transport means (35, 70) for transporting the wafers in the wafer carrier one by one into the heat treatment furnace main body, keeping them there for a predetermined period of time, and then returning the wafers to the wafer carrier.
, 71, 73, 79).