Dresser Cleaning Device and Substrate Polishing Device

Priority is claimed on Japanese Patent Application No. 2024-059926, filed on Apr. 3, 2024, the content of which is incorporated herein by reference.

The present invention relates to a dresser cleaning device and a substrate polishing device.

A chemical mechanical polishing (CMP) device used for polishing a substrate such as a semiconductor wafer includes a polishing table on which a polishing pad is attached on an upper surface of a turntable, and a top ring that holds the substrate between the polishing table and the top ring.

In the CMP device, while rotating each of the polishing table and the top ring, the substrate is pressed against the polishing surface (upper surface) of the polishing pad at a predetermined pressure by the top ring, and the surface of the substrate is polished to be flat and mirror-surface while supplying a polishing liquid to the polishing surface. As the polishing liquid, a liquid in which abrasive grains consisting of fine particles such as silica are suspended in an alkaline solution is normally used. The substrate is polished (chemically and mechanically polished) by a combined action of a chemical polishing action by alkali and a mechanical polishing action by abrasive grains.

The polishing performance of the polishing surface of the polishing pad deteriorates due to the attachment of abrasive grains or polishing debris, and the like, as the substrate is polished. Therefore, the CMP device has a dressing device that regenerates a polishing surface of a deteriorated polishing pad.

The dressing device removes abrasive grains and cutting debris attached to the polishing surface by pressing the dresser driven to rotate against the polishing surface of the polishing table while moving the dresser along the polishing surface and performs flattening and dressing of the polishing surface.

The dresser is cleaned by a dresser cleaning device. The dresser cleaning device sprays a cleaning fluid onto the dresser with a nozzle to clean the dresser (for example, refer to Japanese Unexamined Patent Application, First Publication No. H9-254018 and Japanese Unexamined Patent Application, First Publication No. H11-347917).

The cleaning power in the dresser cleaning is determined by cleaning conditions such as a distance between the nozzle and the dresser, a flow rate, a pressure, or the like of the cleaning fluid. In the dresser cleaning device, cleaning conditions are set so that a certain cleaning power can be obtained, but the actual cleaning effect may vary depending for each device.

An object of an aspect of the present invention is to provide a dresser cleaning device and a substrate polishing device that can obtain a stable cleaning effect.

A dresser cleaning device according to Aspect 1 of the present invention is a dresser cleaning device that cleans a dresser dressing a polishing surface of a polishing pad for polishing a substrate, the device including: a cleaning nozzle that sprays a cleaning fluid for cleaning the dresser onto the dresser; a movement mechanism that moves at least one of the dresser and the cleaning nozzle in a direction in which the dresser and the cleaning nozzle approach each other or separate from each other; a load sensor that detects a load applied to the dresser when the cleaning nozzle sprays the cleaning fluid onto the dresser; and a distance control unit that adjusts a distance between the dresser and the cleaning nozzle using the movement mechanism based on a detection value of the load sensor.

In a dresser cleaning device according to Aspect 2 of the present invention, in the dresser cleaning device according to Aspect 1, the cleaning nozzle is disposed to face a dressing surface of the dresser that is in sliding contact with the polishing surface, and the movement mechanism is a dresser lifting and lowering mechanism that adjusts a height position of the dresser.

A dresser cleaning device according to Aspect 3 of the present invention further includes, in the dresser cleaning device according to Aspect 1 or 2, a cleaning fluid supply unit that supplies the cleaning fluid to the cleaning nozzle, in which the cleaning fluid is a mixed fluid containing a cleaning liquid and a gas.

A substrate polishing device according to Aspect 4 of the present invention includes the dresser cleaning device according to any one of Aspect 1 to Aspect 3, and a polishing table that holds the polishing pad.

An aspect of the present invention provides a dresser cleaning device and a substrate polishing device that can obtain a stable cleaning effect.

Hereinafter, a dresser cleaning device and a substrate polishing device according to an embodiment of the present invention will be described with reference to the drawings.

is a perspective view of a substrate polishing device.is a plan view for describing operations of the dresser swing armand the dresser.is a configuration diagram of a dressing device.is a configuration diagram of a dresser cleaning device.is a partial configuration diagram of the dresser cleaning device.

As shown in, the substrate polishing deviceaccording to an embodiment is provided with a polishing table, a top ring device, a dressing device, a liquid supply mechanism, and a dresser cleaning device. The substrate polishing devicepolishes a substrate such as a semiconductor wafer. For example, the substrate polishing deviceis part of a CMP device that performs polishing, cleaning, and drying of a substrate.

The polishing tableis provided with a turntable. The polishing tablecan be rotated in a direction of the arrow A by a driving force of a motor (not shown). The turntablehas a disk shape. A polishing padcan be attached to an upper surface of the turntable. Therefore, the polishing tablecan hold the polishing pad. The polishing padrotates integrally with the turntable.

The top ring deviceincludes a top ring head, a top ring drive shaft, and a top ring swing arm. The top ring headholds the substrate and presses the substrate against the upper surface of the polishing pad. The top ring drive shaftis connected to the top ring head.

The top ring swing armrotatably holds the top ring drive shaft. The top ring swing armis supported by a top ring swing shaft. A motor (not shown) connected to the top ring drive shaftis installed inside the top ring swing arm. The rotation of the motor is transmitted to the top ring headvia the top ring drive shaft. As a result, the top ring headis rotated in the direction of the arrow B about the top ring drive shaft.

The top ring drive shaftis connected to a vertical movement actuator (for example, an air cylinder) provided in the top ring swing arm. The top ring headvertically moves together with the top ring drive shaftby the vertical movement actuator.

The top ring swing shaftis provided on the radially outer side of the polishing pad. A central axis of the top ring swing shaftextends in the up-down direction. The top ring swing shaftis rotated about a central axis of the top ring swing shaftby a motor (not shown). The top ring devicecauses the top ring swing armto swing by rotating the top ring swing shaftabout the axis. The top ring deviceswitches the position of the top ring headbetween a polishing position and a standby position. The polishing position is a position on the polishing pad. The standby position is a position outside the polishing pad.

The liquid supply mechanismsupplies a polishing liquid and a dressing liquid to a polishing surface of the polishing pad. The liquid supply mechanismis provided with a plurality of supply nozzles. The supply nozzle supplies the polishing liquid and the dressing liquid to the polishing surface of the polishing pad. The liquid supply mechanismserves as both a polishing liquid supply mechanism and a dressing liquid supply mechanism. The polishing liquid supply mechanism supplies the polishing liquid to the polishing pad. The dressing liquid supply mechanism supplies the dressing liquid (for example, pure water) to the polishing pad.

In order to polish the substrate by the substrate polishing device, the substrate is held on the lower surface of the top ring head, and the top ring headand the polishing tableare rotated. In this state, the polishing liquid is supplied to the polishing surface of the polishing pad, and the substrate is pressed against the polishing surface of the polishing padby the top ring head. The surface (lower surface) of the substrate is polished (chemically and mechanically polished) by a combined action of a mechanical polishing action by abrasive grains contained in the polishing liquid and a chemical polishing action of the polishing liquid.

As shown in, the dressing deviceflattens the polishing surfaceof the polishing padand dresses the polishing surface. The dressing deviceis provided with a dresser, a dresser drive shaft, a dresser swing arm(dresser support portion), a dresser swing shaft, a rotation motor, and a swing motor.

The dresserhas a plate shape (for example, a disk shape). The dresseris in sliding contact with the polishing surfaceof the polishing pad. A lower surfaceof the dresseris a dressing surface that is in sliding contact with the polishing surfaceof the polishing pad. Abrasive grains such as diamond particles or the like are fixed to the dressing surface. The dresseris attached to a lower end portion of the dresser drive shaft. The dresser drive shaftprotrudes downward from the dresser swing arm.

The rotation motor(drive source) is provided in the dresser swing arm. The rotation motoris connected to the dresser drive shaft. The rotational force of the rotation motoris transmitted to the dresservia the dresser drive shaft. The rotation motorrotates the dresserin the direction of the arrow C about the dresser drive shaft(refer to).

The dresser swing armis supported by a dresser swing shaft. The dresser swing shaftis provided on the radially outer side of the polishing pad. A central axis of the dresser swing shaftextends in the up-down direction. The swing motor(drive source) rotates the dresser swing shaftabout the central axis.

As shown in, the dresser swing armswings (pivots) by the rotation about the axis of the dresser swing shaft. The dresser swing armmoves the dresseralong the polishing surfaceby swinging (pivoting). The dressercan switch between a dressing position (refer to) and a standby position (refer to) by the swing (pivoting) of the dresser swing arm. The dressing position is a position on the polishing pad. The standby position is a position outside the polishing pad.

As shown in, the dresser cleaning deviceaccording to the first embodiment is provided with a cleaning nozzle, a dresser lifting and lowering mechanism, a load sensor, a distance control unit, and a cleaning fluid supply unit.

The cleaning nozzleis positioned below the dresserat the standby position. The cleaning nozzleis disposed to face the lower surfaceof the dresser. The cleaning nozzleis provided with a nozzle base portionand a plurality of nozzle portions. For example, the nozzle base portionis formed in a plate shape (for example, a disk shape). The nozzle base portionis located at a position facing the lower surfaceof the dresser. For example, the upper surface of the nozzle base portionis parallel to the lower surfaceof the dresser.

The nozzle base portionis located at a position spaced downward from the dresser.

The nozzle portionis provided on the upper surface of the nozzle base portion. The nozzle portionprotrudes in a direction (for example, upward) approaching the dresserfrom the upper surface of the nozzle base portion. The nozzle portionejects the cleaning fluid and sprays the cleaning fluid onto the lower surfaceof the dresser.

For example, the plurality of the nozzle portionsare located at different positions on the upper surface of the nozzle base portion. For example, the plurality of the nozzle portionsinclude one or a plurality of central nozzle portionsA and one or a plurality of peripheral nozzle portionsB. The central nozzle portionA is provided at a central portion of the nozzle base portion. The peripheral nozzle portionB is provided in a peripheral portion surrounding the central portion of the nozzle base portion.

The cleaning fluid supply unitis provided with a cleaning liquid storage unit, a gas supply source, a cleaning fluid supply control unit, and an input device. The cleaning fluid supply unitsupplies a cleaning fluid to the cleaning nozzle.

For example, the cleaning fluid ejected from the nozzle portionis a mixed fluid (gas-liquid mixed fluid) containing a cleaning liquid and a gas. The cleaning liquid storage unitsupplies the cleaning liquid to the cleaning nozzle. For example, the cleaning liquid is water. The gas supply sourcesupplies a gas to the cleaning nozzle. For example, the gas is air. The cleaning fluid is not limited to the gas-liquid mixed fluid and may be only the cleaning liquid or only the gas.

The supply control unitejects the cleaning fluid from the nozzle portionaccording to a predetermined cleaning condition. The input deviceis connected to the supply control unit. The user can input the cleaning condition to the supply control unitby the input device. For example, the input deviceis a keyboard, or the like.

The cleaning power when the dresseris cleaned with the cleaning fluid is determined by cleaning conditions such as a distance between the nozzle portionand the dresser, a flow rate of the cleaning fluid, a pressure of the cleaning fluid, an ejecting time of the cleaning fluid, and the like. The cleaning nozzlemay continuously eject the cleaning fluid or may intermittently eject the cleaning fluid. In a case where the cleaning fluid is intermittently ejected, the ejecting time, the ejecting interval, the number of times of ejecting, and the like are also mentioned as cleaning conditions.

The dresser lifting and lowering mechanismis provided with a support base portion, a connecting portion, a main body portion, and a lifting and lowering motor(drive source). The dresser lifting and lowering mechanismlifts and lowers the dresser.

The support base portionsupports the swing motorprovided at the lower end of the dresser swing shaft.

The connecting portionis connected to the support base portion. The main body portionextends in the up-down direction. The support base portioncan be lifted and lowered along the main body portion. For example, the main body portionlifts and lowers the support base portionby a mechanism using a ball screw operated by the lifting and lowering motor.

When the support base portionis lifted, the dresseris lifted together with the swing motor, the dresser swing shaft, and the dresser swing arm. When the support base portionis lowered, the dresseris lowered together with the swing motor, the dresser swing shaft, and the dresser swing arm.

The dresser lifting and lowering mechanismmoves the dresserin a direction in which the dresserapproaches and separates from the cleaning nozzleby lifting and lowering the dresser. Specifically, the dresseris separated from the cleaning nozzleby lifting. The dresserapproaches the cleaning nozzleby lowering. The dresser lifting and lowering mechanismis an example of a “movement mechanism”.

As shown in, the load sensordetects an upward load (pressing force) applied to the dresserwhen the cleaning nozzlesprays the cleaning fluid onto the dresser. The load sensorhas an insertion holeinto which the dresser drive shaftis inserted. The lower surfaceof the load sensoris fixed to the dresser swing arm. The upper surfaceof the load sensoris fixed to the rotation motor.

The dressercan press an object (for example, the polishing surface) downward with a predetermined force by the dresser lifting and lowering mechanism. When an upward load (pressing force) is applied to the dresser, the load is transmitted to the load sensorthrough the dresser drive shaftand the rotation motor. Therefore, the load sensorcan detect the upward load applied to the dresser. When the load sensordetects the load, the load sensortransmits a detection signal to the distance control unit(refer to).

For example, the load sensoris a strain gauge type load cell. As the load sensor, a pressure sensor, a piezoelectric element, or the like can also be used. An amplifier that amplifies the detection signal may be provided between the load sensorand the distance control unit.

The distance control unitcan adjust the height position of the dresserusing the dresser lifting and lowering mechanismbased on a detection value of the load sensor. The distance control unitcontrols a lifting and lowering operation of the dresser lifting and lowering mechanismsuch that the dresserpresses the object (for example, the polishing surface) with a predetermined force.

An input device(for example, a keyboard or the like) for inputting information necessary for executing a program for determining a relationship between the detection value of the load sensorand the height position of the dressermay be connected to the distance control unit. The input devicecan input a command including the height setting or the like of the dresser.

As shown in, when the polishing surfaceof the polishing padis dressed, the dresseris disposed at a dressing position. The lower surface(dressing surface) of the dresseris brought into sliding contact with the polishing surfaceof the polishing pad. The dresseris rotated about the axis by the rotation motor. The dresser swing armis swung (pivoted) by the rotation of the dresser swing shaftabout the axis to cause the dresserto reciprocate.

By the movement (swinging) of the dresser, the polishing debris or the like attached to the polishing surfaceof the polishing padis removed, and the polishing surfaceis regenerated. During the dressing, a dressing liquid (for example, pure water) is supplied onto the polishing surfaceof the polishing padby the liquid supply mechanism(refer to). The operation of the dressing devicethat dresses the polishing surfaceof the polishing padis also referred to as a “dressing operation”.