KR20040082730A - Apparatus for planarizing a surface of semiconductor substrate - Google Patents

Abstract

PURPOSE: An apparatus for planarizing the surface of a substrate is provided to reduce fabricating cost by eliminating the necessity of slurry used in a CMP(chemical mechanical polishing) process and chemicals for removing the slurry, and to obviate the necessity of a cleaning process using particular chemicals by removing the particles on a substrate by only a cleaning process using deionized water. CONSTITUTION: A planarization process for planarizing the surface of a semiconductor substrate(10) is performed in a process chamber(210). A vacuum chuck(260) absorbs the back surface of the semiconductor substrate by using a vacuum pressure, disposed in the process chamber. A laser oscillating unit(266) irradiates a laser beam in a direction parallel with the front surface of the semiconductor substrate absorbed to the vacuum chuck. A driving unit scans the front surface of the semiconductor substrate by using the laser beam and generates a relative straight line motion between the laser beam and the semiconductor substrate so as to planarize the front surface of the substrate.

Description

Apparatus for planarizing a surface of semiconductor substrate

The present invention relates to a chemical mechanical polishing apparatus. More particularly, the present invention relates to an apparatus for providing a slurry to chemically and mechanically polish the surface of a semiconductor substrate.

Recently, the manufacturing technology of semiconductor devices has been developed to improve the degree of integration, reliability, response speed, etc. in order to meet various needs of consumers. Generally, a semiconductor device is manufactured by forming a predetermined film on a silicon wafer used as a semiconductor substrate and forming the film in a pattern having electrical properties.

The pattern is formed by a sequential or iterative process of various unit processes such as deposition, photolithography, etching, ion implantation, polishing, cleaning, drying for film formation. Among such unit processes, the polishing process has emerged as an important process technology for improving the integration degree of a semiconductor device and improving the structural and electrical reliability of the semiconductor device.

Recently, a semiconductor substrate is formed by chemical reaction between a slurry and a film formed on a semiconductor substrate and a mechanical friction force between foamed bumps formed on the surface of the polishing pad and abrasive particles contained in the slurry and a film formed on the semiconductor substrate. The chemical mechanical polishing process for planarization is mainly used.

1 is a view for explaining an apparatus for performing a conventional chemical mechanical polishing process.

Referring to Figure 1, the chemical mechanical polishing apparatus 100 will be described. The polishing pad 102 is attached to the upper surface of the rotary table 104, and a rotary shaft 106 that provides rotational force is connected to the lower surface of the rotary table 104. An upper portion of the polishing pad 102 is provided with a polishing head 110 for adsorbing the semiconductor substrate 10, and the polishing head 110 performs rotation and translational movements during polishing of the semiconductor substrate 10. The semiconductor substrate 10 is moved up and down before and after. A pad conditioner 120 is provided on the opposite side of the polishing head 110 with respect to the center of the polishing pad 102 to improve the surface condition of the polishing pad 102. In addition, a slurry supply unit 130 for supplying a slurry 130a onto the polishing pad 102 is provided. In addition, the slurry 130a supplied onto the polishing pad 102 is accommodated in a number of foamed pores formed in the polishing pad 102, and contacts the polishing pad 102 with the relative movement of the semiconductor substrate 10. Polish the surface chemically and mechanically.

In the case of the chemical mechanical polishing apparatus as described above, since the process of polishing the semiconductor substrate is performed by applying a very high pressure, the film has a high dependency on the pattern density of the thin film, and according to the type of slurry provided to polish the semiconductor substrate. Since the process variables of substrate polishing vary, it is not easy to find suitable process conditions.

In addition, the chemical mechanical polishing apparatus is very difficult to maintain the polishing uniformity as well as uniform process variables because the dependence on the process parameters of each of the parts is very strong. In addition, since the price of the head, the polishing pad, and the slurry, which are consumable parts, is high, the manufacturing cost of the semiconductor device is increased due to the replacement of parts and the use of the slurry.

An object of the present invention for solving the above problems is to provide a surface planarization apparatus of a substrate using a laser beam.

1 is a view for explaining an apparatus for performing a conventional chemical mechanical polishing process.

2 is a schematic cross-sectional view illustrating a substrate planarization apparatus according to an embodiment of the present invention.

FIG. 3 is a schematic plan view for describing the substrate planarization apparatus shown in FIG. 2.

4A and 4B are cross-sectional views illustrating a surface planarization process of a semiconductor substrate by a laser beam.

5 is a schematic cross-sectional view for describing a substrate planarization apparatus according to another exemplary embodiment of the present invention.

FIG. 6 is a schematic plan view for describing the substrate planarization apparatus illustrated in FIG. 5.

Explanation of symbols on the main parts of the drawings

10: semiconductor substrate 200: substrate planarizing device

210: process chamber 220: cleaning chamber

230: Load cassette 240: Unload cassette

250a to 250c: first to third transfer chamber

252a to 252c: first to third transfer robot

260: vacuum chuck 266: laser oscillator

268: beam detection unit 270: data processing unit

274: vacuum pump 280: rotary chuck

284: nozzle pipe

The polishing method of the present invention for achieving the above object is a process chamber for performing a planarization process for planarizing the surface of the semiconductor substrate, and disposed inside the process chamber, by using a vacuum pressure to back the semiconductor substrate A vacuum chuck for adsorption, a laser oscillator for irradiating a laser beam in a direction parallel to the front surface of the semiconductor substrate adsorbed on the vacuum chuck, and the entire surface of the semiconductor substrate is planarized by scanning the entire surface of the semiconductor substrate with the laser beam To provide a substrate planarization apparatus comprising a drive means for generating a relative linear motion between the laser beam and the semiconductor substrate.

A curved surface is formed on the semiconductor substrate by performing various unit processes. The uneven portion of the surface of the semiconductor substrate as described above is removed by a laser beam, thereby flattening the surface of the semiconductor substrate. During the planarization process, the height of the semiconductor substrate is precisely controlled to adjust the distance between the laser beam and the surface of the semiconductor substrate, and the laser beam removes surface irregularities of the semiconductor substrate.

The foreign substances generated during the planarization process as described above, that is, particles generated by being removed from the surface of the semiconductor substrate by the laser beam, are removed from the process chamber by the operation of a vacuum pump connected to the process chamber.

A beam detector for detecting the laser beam irradiated from the laser oscillator and measuring the intensity of the laser beam inside the process chamber, and comparing the intensity of the measured laser beam with a reference intensity to stop the end of the planarization process. A data processing unit for detecting point detection is disposed. While the laser beam irradiated from the laser oscillator removes the surface of the semiconductor substrate, the intensity of the laser beam detected by the beam detector decreases, and when the surface of the semiconductor substrate is flattened to a desired thickness, the laser beam detected by the beam detector The intensity of is equal to the reference intensity. Here, the reference intensity is equal to the initial intensity of the laser beam generated from the laser oscillator.

In addition, the substrate planarized by the laser beam is cleaned by a cleaning unit connected with the process chamber. The cleaning unit includes a cleaning chamber connected to the process chamber, a rotation chuck for supporting and rotating the semiconductor substrate in the cleaning chamber, and a nozzle pipe for supplying the cleaning liquid to which the ultrasonic vibration is applied to the semiconductor substrate. Here, since particles generated during the substrate planarization process are discharged from the process chamber, only a small amount of particles remain on the semiconductor substrate. Remaining particles as described above are completely removed by deionized water to which ultrasonic vibration is applied.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a schematic cross-sectional view for describing a substrate planarization apparatus according to an embodiment of the present invention, and FIG. 3 is a schematic plan view for explaining the substrate planarization apparatus illustrated in FIG. 2.

2 and 3, the substrate planarization apparatus 200 according to the embodiment includes a process chamber 210 and a planarized semiconductor substrate 10 for performing a surface planarization process of the semiconductor substrate 10. A cleaning chamber 220 for cleaning, a load cassette 230 for accommodating a plurality of semiconductor substrates 10 for performing a substrate planarization process, and an unload cassette 240 for accommodating the flattened semiconductor substrate 10. And a plurality of transfer chambers 250a, 250b, 250c disposed between the load cassette 230, the process chamber 210, the cleaning chamber 220, and the unload cassette 240 to transfer the semiconductor substrate 10. ). That is, the components include the load cassette 230, the first transfer chamber 250a, the process chamber 210, the second transfer chamber 250b, the cleaning chamber 220, the third transfer chamber 250c and the unload cassette. Are connected in the order of 240.

First to third transfer robots 252a, 252b, and 252c for transferring the semiconductor substrate 10 are disposed in the first to third transfer chambers 250a, 250b, and 250c, and the process chamber 210 may be disposed. Inside the vacuum chuck 260 for adsorbing the semiconductor substrate 10 using a vacuum pressure, the first driving unit 262 for horizontal linear reciprocating motion of the vacuum chuck 260, and the vacuum chuck 260 A second driver 264 for moving the light in a vertical direction, a laser oscillator 266 for irradiating a laser beam to planarize the entire surface of the semiconductor substrate 10, and a beam detector for detecting the irradiated laser beam ( 268 is disposed.

The semiconductor substrate 10 transferred to the process chamber 210 through the first transfer robot 252a is mounted on the vacuum chuck 260 so that the front surface thereof faces upward. Although not shown, the semiconductor substrate 10 is aligned by an alignment member (not shown) such that the center of the semiconductor substrate 10 coincides with the central axis of the vacuum chuck 260. Subsequently, the semiconductor substrate 10 is adsorbed by the vacuum pressure on the upper surface of the vacuum chuck 260. The semiconductor substrate 10 adsorbed by the vacuum chuck 260 is adjusted to a preset height set by the second driver 264. That is, the front surface of the semiconductor substrate 10 is adjusted to a height in contact with the laser beam irradiated from the ray oscillator 266.

The laser oscillator 266 and the beam detector 268 are disposed on both sides of the semiconductor substrate 10, and the irradiation direction of the laser beam is perpendicular to the transfer direction of the semiconductor substrate 10. The laser oscillator 266 irradiates the laser beam in a direction parallel to the entire surface of the semiconductor substrate 10. As shown, the transfer direction of the semiconductor substrate 10 is in the x-axis direction, and the irradiation direction of the laser beam is in the y-axis direction.

Subsequently, the first driver 262 moves the semiconductor substrate 10 in the horizontal direction to planarize the entire surface of the semiconductor substrate 10 by the laser beam. That is, the first driver 262 flattens the semiconductor substrate 10 by linearly reciprocating the semiconductor substrate 10 in the x-axis direction so that the irradiated laser beam scans the entire surface of the semiconductor substrate 10. In this case, the second driver 264 may adjust the height of the semiconductor substrate 10 to control the planarization speed of the semiconductor substrate 10. That is, since the amount of material removed from the front surface of the semiconductor substrate 10 is adjusted according to the height and the transfer speed of the semiconductor substrate 10, the semiconductor is controlled by controlling the operations of the first driver 262 and the second driver 264. The degree of planarization of the entire surface of the substrate 10 may be adjusted. Here, a control unit (not shown) for controlling the operation of the first driving unit 262 and the second driving unit 264 and the intensity of the laser beam is not shown in the drawing, but a control unit according to a general technical degree may be configured. Can be.

The beam detector 268 detects a laser beam that has passed through the semiconductor substrate 10. At this time, the intensity of the laser beam is changed depending on the degree of contact with the front surface of the semiconductor substrate 10. The intensity of the laser beam detected by the beam detector 268 is transmitted to the data processor 270, and the data processor 270 compares the intensity of the detected laser beam with a reference intensity to planarize the semiconductor substrate 10. The stop point of time is detected.

As shown in FIGS. 4A and 4B, when patterns and a film to be removed are formed on the semiconductor substrate 10, when the film is flattened to a desired thickness, the beam irradiated from the laser oscillator 266 becomes a semiconductor substrate. Since it is irradiated directly to the beam detector 268 without being interfered by (10), the beam detector 268 detects the same intensity as the reference intensity. As described above, the point in time at which the reference intensity is equal to the detected intensity becomes the stopping point of the planarization process.

At this time, the process chamber 210 is connected to the discharge pipe 272 for discharging the particles generated by the laser beam from the front surface of the semiconductor substrate 10 during the substrate planarization process, the discharge pipe 272 is a vacuum pump The pressure control valve 276 is connected to the discharge pipe 272.

As described above, the flattened semiconductor substrate 10 is loaded onto the rotary chuck 280 of the cleaning chamber 220 by the second transfer robot 252b. The rotary chuck 280 sucks and rotates the semiconductor substrate 10 using a vacuum pressure. A third driving part 282 for rotating the semiconductor substrate 10 is connected to the lower part of the rotary chuck 280, and the nozzle pipe 284 is movable in the horizontal direction by the fourth driving part 286.

The nozzle pipe 284 is disposed across the semiconductor substrate 10 above the front surface of the semiconductor substrate 10, has a pipe shape, and has a plurality of cleaning nozzles for supplying a cleaning liquid to the front surface of the semiconductor substrate 10. . Particles remaining on the semiconductor substrate 10 are removed by the centrifugal force by rotation and the cleaning liquid supplied from the nozzle pipe 284. Most of the particles generated during the substrate planarization process are removed by the operation of the vacuum pump 274, and the remaining particles remaining on the semiconductor substrate 10 are removed from the cleaning chamber 220 to maximize the cleaning efficiency.

At this time, deionized water may be used as the cleaning liquid supplied onto the semiconductor substrate 10, and more preferably deionized water to which ultrasonic vibration is applied may be used. Although not shown, the substrate planarization apparatus 200 may further include an ultrasonic generator (not shown) for applying the ultrasonic vibration. Deionized water including particles removed from the front surface of the semiconductor substrate 10 is discharged through the drain pipe 288 connected to the cleaning chamber 220.

The semiconductor substrate 10 cleaned as described above is accommodated in the unload cassette 240 by the third transfer robot 252c.

5 is a schematic cross-sectional view for describing a substrate planarization apparatus according to another exemplary embodiment of the present invention, and FIG. 6 is a schematic plan view for explaining the substrate planarization apparatus illustrated in FIG. 5.

5 and 6, another substrate planarization apparatus 300 according to another embodiment may include a process chamber 310 for performing a substrate planarization process, a cleaning chamber 320 for performing a cleaning process, and a load cassette ( 330, unload cassette 340, and first to third transfer chambers 350a, 350b, 350c.

In the process chamber 310, a vacuum chuck 360 for adsorbing the semiconductor substrate 10 using a vacuum pressure and a laser in a direction parallel to the front surface of the semiconductor substrate 10 adsorbed to the vacuum chuck 360. A laser oscillator 366 for irradiating a beam, a beam detector 368 for detecting a laser beam, a laser oscillator 366 and a beam detector 368 so that the laser beam scans the entire surface of the semiconductor substrate 10. First driver 362 for moving the light in the horizontal direction, and second driver 364 for moving the vacuum chuck 360 in the vertical direction to adjust a distance between the laser beam and the front surface of the semiconductor substrate 10. ) Is installed.

The cleaning chamber 320 includes a rotary chuck 380 for rotating the semiconductor substrate 10, a third driver 382 for providing rotational force, and a nozzle pipe for supplying a cleaning liquid onto the semiconductor substrate 10 ( The 384 and the 4th drive part 386 for moving the nozzle pipe 384 in a horizontal direction are arrange | positioned, and the drain piping 388 is connected.

First to third transfer robots 352a, 352b, and 352c are disposed in the first to third transfer chambers 350a, 350b, and 350c, and the load cassette 330 and the unload cassette 340 are opposed to each other. It is connected to the 1st transfer chamber 350a and the 3rd transfer chamber 350c, respectively.

Further detailed descriptions of the above components will be omitted since they have been described with reference to the substrate planarization apparatus according to the embodiment of the present invention shown in FIGS. 2 and 3.

According to the present invention as described above, the surface of the semiconductor substrate is planarized by scanning of the laser beam. Particles generated during the process of planarizing the surface of the semiconductor substrate are discharged by the operation of the vacuum pump connected to the process chamber, and the semiconductor is rotated by the rotation of the semiconductor substrate and the cleaning liquid to which ultrasonic vibration is applied during the cleaning process. It is removed from the substrate.

The effects of the planarization process using the substrate planarization apparatus using the laser beam as described above are compared with the planarization process using the conventional chemical mechanical polishing apparatus.

First, in the chemical mechanical polishing process, scratching or dishing of the surface of the semiconductor substrate caused by a poor pressure regulation that adheres the semiconductor substrate held by the polishing head to the polishing pad is eliminated.

Second, since the slurry used in the chemical mechanical polishing process is unnecessary, the cost of using the slurry is reduced, and the use of the chemical liquid for removing the slurry remaining on the semiconductor substrate is unnecessary, thereby reducing the cost of using the chemical liquid. That is, in the planarization process using a laser beam, since the particles on the semiconductor substrate are removed only by the cleaning process using deionized water, the cleaning process using a specific chemical agent is unnecessary.

Third, the use of polishing pads, pad conditioners and other consumables is unnecessary, thereby reducing the cost.

Fourth, the time required for the surface planarization process of the semiconductor substrate is reduced.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (8)

A process chamber for performing a planarization process for planarizing a surface of the semiconductor substrate; A vacuum chuck disposed inside the process chamber and configured to suck a rear surface of the semiconductor substrate using a vacuum pressure; A laser oscillator for irradiating a laser beam in a direction parallel to the front surface of the semiconductor substrate adsorbed on the vacuum chuck; And And driving means for generating relative linear motion between the laser beam and the semiconductor substrate to scan the entire surface of the semiconductor substrate with the laser beam to planarize the entire surface of the semiconductor substrate. The method of claim 1, further comprising a vacuum pump connected to the process chamber to form an interior of the process chamber in a vacuum state, and to discharge particles generated during the planarization process from the process chamber. A substrate planarization apparatus characterized by the above-mentioned. The method of claim 1, wherein the drive means, A first driving part connected to the vacuum chuck and moving the vacuum chuck in a horizontal direction perpendicular to the irradiation direction of the laser beam to generate the relative linear motion; And A second driving part connected to the vacuum chuck and configured to move the vacuum chuck in a vertical direction to adjust a distance between the laser beam and the front surface of the semiconductor substrate adsorbed by the vacuum chuck. . The laser beam of claim 1, wherein the laser beam is irradiated from the laser oscillator, the laser beam irradiated from the laser oscillator, and disposed to face the vacuum oscillator. A substrate planarization apparatus further comprises a beam detection unit for performing. The substrate flattening apparatus of claim 4, further comprising a data processor configured to detect an interruption point of the planarization process by comparing the measured intensity of the laser beam with a reference intensity. The method of claim 4, wherein the drive means, A first driver connected to the laser oscillator and the beam detector and configured to move the laser oscillator and the beam detector in a horizontal direction perpendicular to the irradiation direction of the laser beam to generate the relative linear motion; And A second driving part connected to the vacuum chuck and configured to move the vacuum chuck in a vertical direction to adjust a distance between the laser beam and the front surface of the semiconductor substrate adsorbed by the vacuum chuck. . The substrate flattening apparatus of claim 1, further comprising a cleaning unit connected to the process chamber and configured to clean the semiconductor substrate flattened by the laser beam. The method of claim 7, wherein the cleaning unit, A cleaning chamber connected to one side of the process chamber; A rotary chuck disposed inside the cleaning chamber, the rotary chuck supporting and rotating the flattened semiconductor substrate; And And a nozzle pipe for supplying a cleaning liquid to which ultrasonic vibration is applied to a front surface of the semiconductor substrate supported on the rotary chuck.