JP5334908B2 - HMDS processor - Google Patents

Description

  The present invention relates to an HMDS processing apparatus, and more particularly to an HMDS processing apparatus for hydrophobizing a wafer surface in a semiconductor manufacturing process.

  In general, in a photoresist coating process in a semiconductor manufacturing process, moisture (OH group) and HMDS (hexamethyldisilazane) on the wafer surface are replaced before resist coating in order to improve the adhesion between the photoresist and the wafer. Thus, the HMDS process for hydrophobizing the wafer surface is performed.

  A conventional HMDS processing apparatus that performs such processing is a HMDS processing chamber for hydrophobizing the wafer surface, a hot plate for placing a wafer in the HMDS processing chamber, and a HMDS steam for introducing HMDS vapor into the HMDS processing chamber. It is composed of a bubbling tank that vaporizes the HMDS liquid into steam and a gas pipe that connects these.

  Nitrogen gas is introduced into the bubbling tank, and the HMDS liquid is bubbled with the nitrogen gas to generate HMDS vapor. The generated HMDS vapor flows to the HMDS processing chamber through the gas pipe and is applied to the surface of the wafer installed in the HMDS processing chamber. The remaining HMDS vapor that has not been applied to the surface of the wafer is further exhausted from the HMDS processing chamber through a gas pipe (see Patent Document 1).

JP-A-7-14211

  The results of the HMDS process for hydrophobizing the wafer surface are greatly affected by process conditions such as the amount of HMDS liquid in the bubbling tank, the concentration of HMDS vapor applied to the wafer, the temperature of the hot plate, the time for the hydrophobization process, etc. Therefore, when the process conditions fluctuate, there is a problem that the wafer surface cannot be hydrophobized, the adhesion between the photoresist and the wafer is lowered, and the photoresist pattern may be peeled off after exposure and development.

  In addition, in order to stably perform HMDS processing, various managements such as the amount of HMDS liquid, the concentration of HMDS vapor, the flow rate, the temperature of the hot plate, etc. are necessary. In order to optimize and stabilize each condition It took a lot of time and effort.

  In addition, in order to determine whether or not the processed wafer surface is actually hydrophobized, there is a method of dropping water droplets on the wafer surface and measuring the contact angle, but in a fully automatic resist coating apparatus, Since the resist coating is performed after the processing, it is virtually impossible to determine whether or not it is hydrophobized, and the photoresist pattern is not peeled off after the applied photoresist is actually exposed and developed. There was no choice but to check.

  The present invention is intended to solve these problems, and an object of the present invention is to provide an HMDS processing apparatus that can easily perform HMDS processing for making a hydrophobic surface of a wafer stable.

  The HMDS processing apparatus according to the present invention includes an HMDS processing chamber into which HMDS gas is introduced, a hot plate that is installed in the HMDS processing chamber and on which a semiconductor substrate to be processed is placed, the HMDS gas and the HMDS gas in the HMDS processing chamber. A sensor that detects the concentration of ammonia gas generated by the reaction with the semiconductor substrate to be processed, and a controller that controls the increase and decrease of the output heat of the hot plate according to the detection value of the sensor.

  According to the HMDS processing apparatus of the present invention, a HMDS processing chamber into which HMDS gas is introduced, a hot plate that is installed in the HMDS processing chamber and on which a semiconductor substrate to be processed is placed, and the HMDS gas in the HMDS processing chamber. And a sensor that detects the concentration of ammonia gas generated by the reaction between the semiconductor substrate and the semiconductor substrate to be processed, and a controller that controls the increase and decrease of the output heat of the hot plate according to the detection value of the sensor. Stable HMDS treatment is possible by reliably saturating ammonia gas within the treatment time.

It is a figure which shows the structure of the HMDS processing apparatus by Embodiment 1 of this invention. It is a figure explaining the relationship between ammonia gas concentration and hotplate temperature control by Embodiment 1 of this invention. It is a figure which shows the structure of the HMDS processing apparatus by prerequisite technology. It is a figure explaining the HMDS process by a base technology.

<Prerequisite technology>
FIG. 3 is a diagram illustrating a configuration of the HMDS processing apparatus according to the base technology. As shown in the figure, the premise HMDS treatment apparatus includes a pipe 6 into which nitrogen gas is introduced, a valve 9 for controlling the flow rate of the pipe 6, a pressure gauge 11 for measuring the pressure in the pipe 6, and the pipe 6. A bubbling tank 2 in which the supplied nitrogen gas is bubbled, a HMDS liquid 3 filled in the bubbling tank 2, a pipe 7 into which HMDS vapor generated by bubbling in the bubbling tank 2 is introduced, and a pipe 7 The HMDS processing chamber 1 to which HMDS vapor is supplied via the flow meter 12 and the pipe 7, the hot plate 4 disposed in the HMDS processing chamber 1, and the hot plate 4 are disposed on the hot plate 4. A wafer 5, a pipe 8 for exhausting the gas in the HMDS processing chamber 1, and a valve 10 for controlling the flow rate of the pipe 8 are provided.

  The vaporized HMDS vapor flows to the HMDS processing chamber 1 through the pipe 7 and is applied to the surface of the wafer 5. The remaining HMDS vapor that has not been applied to the surface of the wafer 5 is exhausted from the HMDS processing chamber 1 through the pipe 8.

  FIG. 4 is a reaction formula showing how HMDS vapor applied to the surface of the wafer 5 and OH groups such as moisture adhering to the surface of the wafer 5 are combined to be hydrophobized. The HMDS vapor applied to the surface of the wafer 5 is replaced with OH groups on the surface of the wafer 5 by the thermal energy of the hot plate 4 to generate ammonia gas. As a result of this reaction, an organic compound is formed on the surface of the wafer 5, so that the adhesion with the photoresist, which is an organic material, is improved.

  A technique that enables more stable HMDS processing in the HMDS processing apparatus of FIG. 3 will be described in detail below.

<A. Embodiment 1>
<A-1. Configuration>
Hereinafter, the HMDS processing apparatus according to the first embodiment of the present invention will be described in detail with reference to FIG. As shown in the figure, the HMDS processing apparatus according to the present invention includes a pipe 6 into which nitrogen gas is introduced, a valve 9 for controlling the flow rate of the pipe 6, a pressure gauge 11 for measuring the pressure in the pipe 6, and a pipe 6 A bubbling tank 2 in which nitrogen gas supplied from the bubbling tank 2 is bubbled, a HMDS liquid 3 filled in the bubbling tank 2, a pipe 7 into which HMDS vapor generated by bubbling in the bubbling tank 2 is introduced, and a pipe 7, a flow meter 12 for measuring, a HMDS processing chamber 1 to which HMDS vapor is supplied via a pipe 7, a hot plate 4 disposed in the HMDS processing chamber 1, and a hot plate 4. A wafer 5 as a semiconductor substrate to be processed, a hot plate temperature control unit 16 for controlling the temperature rise and fall of the hot plate 4, and an HMDS gas. Gas sensor 13 for detecting ammonia gas generated in HMDS processing chamber 1 by reaction with wafer 5, gas concentration meter 14 for measuring the concentration of ammonia gas detected by gas sensor 13, and output of gas concentration meter 14 And a valve control unit 15 for controlling the valves 9, 10 and the hot plate temperature control unit 16, a pipe 8 for exhausting the gas in the HMDS processing chamber 1, and a valve 10 for controlling the flow rate of the pipe 8. Is provided.

<A-2. Operation>
Hereinafter, the operation of the HMDS processing apparatus will be specifically described. Nitrogen gas is added through the pipe 6 into the bubbling tank 2 filled with the HMDS solution 3. At this time, the flow rate of nitrogen gas is set to 0.1 to 0.5 L / min as an initial state of the opening degree of the valve 9.

  In the bubbling tank 2, the HMDS liquid 3 is bubbled by the introduced nitrogen gas and becomes HMDS vapor through the pipe 7. When the valve 9 and the valve 10 are opened, the generated HMDS vapor flows into the HMDS processing chamber 1 and is applied to the surface of the wafer 5.

  The HMDS vapor applied to the surface of the wafer 5 is replaced with OH groups on the surface of the wafer 5 by the thermal energy of the hot plate 4 to generate ammonia gas. The initial set temperature of the hot plate 4 at this time is set to 110 to 125 ° C., which is near the boiling point of the HMDS material.

  The ammonia gas generated here is detected by the gas sensor 13, and its concentration is measured by the gas concentration meter 14. The valve control unit 15 controls the hot plate temperature control unit 16 according to the measured value, adjusts the temperature of the hot plate 4, and controls the opening degree of the valves 9 and 10.

  Specifically, as shown in FIG. 2, when the concentration of ammonia gas measured by the gas concentration meter 14 is high, the temperature of the hot plate 4 is lowered and the opening degree of the valves 9 and 10 is closed. Control. On the other hand, when the ammonia gas concentration measured by the gas concentration meter 14 is low, the temperature of the hot plate 4 is raised and the opening of the valves 9 and 10 is controlled to be opened. Further, the degree of temperature increase / decrease of the hot plate 4 is also controlled in accordance with the ammonia gas concentration value. With these controls, the ammonia gas can be reliably saturated within the processing time, so that stable HMDS processing can be performed, and the surface of the wafer 5 can be reliably hydrophobized.

<A-3. Effect>
According to the first embodiment of the present invention, in the HMDS processing apparatus, the HMDS processing chamber 1 into which HMDS gas is introduced, and the wafer 5 which is a semiconductor substrate to be processed are placed in the HMDS processing chamber 1. The gas sensor 13, the gas concentration meter 14, the gas sensor 13, and the gas concentration meter 14, which are sensors for detecting the concentration of ammonia gas generated by the reaction between the HMDS gas and the wafer 5 in the hot plate 4 and the HMDS processing chamber 1. By providing the valve control unit 15 and the hot plate temperature control unit 16, which are control units that control the increase and decrease of the output heat of the hot plate 4 according to the detected value, the ammonia gas is reliably saturated within the processing time. Stable HMDS processing becomes possible.

  Moreover, since the reaction product gas of HMDS vapor | steam is detected directly, even when resist application is continued after HMDS process, it can be determined whether hydrophobicity is made reliably. As a result, resist peeling can be suppressed.

  Moreover, since the HMDS process can be performed while directly detecting the ammonia concentration, the process conditions can be easily optimized, and the process development period can be shortened.

  Further, according to the first embodiment of the present invention, in the HMDS processing apparatus, the valve control unit 15 that is a control unit and the hot plate temperature control unit 16 are detected values in the gas sensor 13 and the gas concentration meter 14 that are sensors. When the temperature is high, the output heat of the hot plate 4 is lowered, and when the detection values in the gas sensor 13 and the gas concentration meter 14 are low, the output heat of the hot plate 4 is controlled to be stabilized, thereby stabilizing the ammonia gas concentration. Since it can be surely saturated, the HMDS process is stabilized.

  1 HMDS processing chamber, 2 bubbling tank, 3 HMDS liquid, 4 hot plate, 5 wafer, 6, 7, 8 piping, 9, 10 valve, 11 pressure gauge, 12 flow meter, 13 gas sensor, 14 gas concentration meter, 15 Valve control unit, 16 hot plate temperature control unit.

Claims (2)

An HMDS processing chamber into which HMDS gas is introduced;
A hot plate installed in the HMDS processing chamber for mounting a semiconductor substrate to be processed;
A sensor for detecting a concentration of ammonia gas generated by a reaction between the HMDS gas and the semiconductor substrate to be processed in the HMDS processing chamber;
A control unit that controls the raising and lowering of the output heat of the hot plate according to the detection value in the sensor,
HMDS processor. The control unit performs control to lower the output heat of the hot plate when the detection value in the sensor is high, and to increase the output heat of the hot plate when the detection value in the sensor is low.
The HMDS processing apparatus according to claim 1.

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