Substrate treatment apparatus, method of manufacturing semiconductor device and workpiece substrate

In one embodiment, a substrate treatment apparatus includes a substrate holder configured to hold a substrate provided with a film. The apparatus further includes a film treatment module configured to treat the film in accordance with warpage of the substrate such that the film includes a first region having a first film quality or a first film thickness and a second region having a second film quality or a second film thickness different from the first film quality or the first film thickness.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2018-172284, filed on Sep. 14, 2018, the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate to a substrate treatment apparatus, a method of manufacturing a semiconductor device and a workpiece substrate.

BACKGROUND

A film formed on a surface of a wafer may inhibit warpage of the wafer.

DETAILED DESCRIPTION

In one embodiment, a substrate treatment apparatus includes a substrate holder configured to hold a substrate provided with a film. The apparatus further includes a film treatment module configured to treat the film in accordance with warpage of the substrate such that the film includes a first region having a first film quality or a first film thickness and a second region having a second film quality or a second film thickness different from the first film quality or the first film thickness.

Embodiments will now be explained with reference to the accompanying drawings. InFIGS. 1 to 7, the identical or similar configuration is denoted by the same reference numeral, and an overlapping explanation thereof is omitted.

First Embodiment

FIG. 1is a cross-sectional view schematically showing a configuration of a substrate treatment apparatus of a first embodiment. The substrate treatment apparatus inFIG. 1is a plasma treatment apparatus that treats a film2provided on a wafer1by using plasma.

The wafer1is a semiconductor wafer such as a silicon wafer, for example. The wafer1is an example of a substrate. The wafer1has a first surface S1on which a device is formed or is to be formed, and a second surface S2on which the film2for inhibiting warpage of the wafer1is formed. Here, the device includes, for example, a discrete semiconductor device such as a transistor, or an integrated circuit. The film2is a silicon film, a silicon oxide film, a silicon nitride film, or a metal film, for example. The film2may be formed on the wafer1for the purpose of inhibiting the warpage, or may be formed on the wafer1for other purposes.

FIG. 1shows an X direction and a Y direction which are substantially parallel to the center region of the first surface S1and the second surface S2of the wafer1and are perpendicular to each other, and shows a Z direction which is substantially perpendicular to the center region of the first surface S1and the second surface S2of the wafer1. Herein, a +Z direction is regarded as an upward direction, and a −Z direction is regarded as a downward direction. The −Z direction may match the gravity direction, or may not match the gravity direction. The Y direction is an example of a first direction, and the X direction is an example of a second direction.

The substrate treatment apparatus inFIG. 1includes a wafer holder11, a warpage measurement instrument12, a plasma irradiator13and a controller14. The wafer holder11is an example of a substrate holder. The plasma irradiator13and the controller14is an example of a film treatment module.

The wafer holder11holds the wafer1on which the film2is provided. For example, the wafer holder11holds a bevel of the wafer1. The bevel of the wafer1is an example of an edge of a substrate. The film2of the present embodiment is formed on the wafer1before the wafer1is held by the wafer holder11. However, the film2may be formed on the wafer1in a state where the wafer1is held by the wafer holder11.

The warpage measurement instrument12measures, in a non-contact manner, warpage of the wafer1held by the wafer holder11. The warpage measurement instrument12includes a light source that irradiates the first surface S1side of the wafer1with light, and a detector that detects the light reflected by the first surface S1side of the wafer1. The warpage measurement instrument12measures the warpage of the wafer1on the basis of the detection result of the light by the detector. The warpage measurement instrument12outputs the measurement result of the warpage of the wafer1to the controller14.

An arrow K indicates that, while irradiating the wafer1with light, the warpage measurement instrument12moves in the horizontal direction so as to scan the wafer1with the light. Accordingly, various points on the wafer1are irradiated with the light so that the warpage of the wafer1can be measured. For example, the edge of the wafer1is scanned with the light by 360 degrees so that the warpage of the wafer1can be efficiently measured.

The warpage measurement instrument12may measure the warpage of the wafer1held by the wafer holder11by another technique. For example, the warpage measurement instrument12may be a position sensor provided on a wafer chuck portion of the wafer holder11. In this case, the warpage of the wafer1is measured by the position sensor, and the measurement result of the warpage of the wafer1is outputted from the position sensor to the controller14.

The plasma irradiator13irradiates the film2with plasma. Accordingly, stress applied to the wafer1from the film2is changed so that the warpage of the wafer1can be changed. The plasma irradiator13of the present embodiment irradiates the film2with plasma under normal temperature and normal pressure.FIG. 1shows a plasma irradiation nozzle constituting the plasma irradiator13.

The controller14controls various operations of the substrate treatment apparatus inFIG. 1. Examples of the controller14include a processor, an electric circuit, and a PC (personal computer). For example, the controller14controls the operation of the wafer holder11, the measurement which is performed by the warpage measurement instrument12, the plasma irradiation which is performed by the plasma irradiator13, and the like.

The controller14controls the plasma irradiation of the film2by the plasma irradiator13in accordance with the measurement result of the warpage of the wafer1outputted from the warpage measurement instrument12. Accordingly, the film2can be treated such that the warpage of the wafer1is inhibited. In the present embodiment, the film2is partially modified (reformed) with plasma, whereby the warpage of the wafer1is inhibited. An example of modification of the film2is oxidation or nitridation of a part of the film2through plasma irradiation. Other examples of modification of the film2include partially reducing or increasing the thickness of the film2by plasma irradiation.

Under control by the controller14, the plasma irradiator13irradiates the film2with plasma and scans the film2with the plasma, thereby partially modifies the film2. An arrow A1indicates that the plasma irradiation nozzle horizontally moves during the irradiation so that the film2is scanned with the plasma. An arrow B1indicates that the plasma irradiation nozzle vertically moves during the plasma irradiation, so that the density or area of the plasma irradiation is modulated. The controller14determines a plasma irradiation position or a plasma irradiation condition in accordance with the measurement result of the warpage of the wafer1, and controls the plasma irradiation in accordance with the determined irradiation position or the determined irradiation condition. As a result, the film2is partially modified. Which part of the film2is modified is described later in detail.

The wafer1is commonly conveyed with the first surface S1directed upward. In contrast, the wafer1inFIG. 1is held by the wafer holder11with the first surface S1directed downward. Therefore, the substrate treatment apparatus inFIG. 1may include an inversion unit that inverts the direction of the first surface S1of the wafer1. In this case, the direction of the first surface S1of the wafer1is inverted from the upward direction to the downward direction before the wafer1is mounted on the wafer holder11, and the first surface S1of the wafer1is inverted from the downward direction to the upward direction after the wafer1is detached from the wafer holder11.

The film2of the present embodiment is formed on the wafer1outside the substrate treatment apparatus inFIG. 1. However, the film2may be formed on the wafer1inside the substrate treatment apparatus inFIG. 1. For example, the film2may be formed on the wafer1with plasma from the plasma irradiator13after the wafer1is mounted on the wafer holder11. The film2formed on the wafer1may be etched or removed inside the substrate treatment apparatus inFIG. 1.

FIGS. 2A to 4Care diagrams for explaining a wafer treatment method of the first embodiment. Note that, unlikeFIG. 1, each ofFIGS. 2A to 4Cillustrates that the first surface S1of the wafer1is directed upward, and the second surface S2of the wafer1is directed downward.

FIGS. 2A, 2B and 2Crespectively show an XZ cross section, a YZ cross section and the second surface S2of the wafer1before formation of the film2on the second surface S2of the wafer1. However, another film (not illustrated) is already formed on the first surface S1or/and the second surface S2of the wafer1. As a result, the wafer1is warped into an upwardly projected shape along the X direction (FIG. 2A), and is warped into a downwardly projected shape along the Y direction (FIG. 2B).

FIGS. 3A, 3B and 3Crespectively show the XZ cross section, the YZ cross section and the second surface S2of the wafer1after formation of the film2on the wafer1but before modification of the film2. The film2of the present embodiment isotropically applies compressive stress to the wafer1. Consequently, the compressive stress is applied to the wafer1in the X direction and the Y direction. Since the compressive stress is applied to the wafer1so as to widen the second surface S2, the film2inhibits the upwardly projected warpage (FIG. 3A), but the film2increases the downwardly projected warpage (FIG. 3B).

FIGS. 4A, 4B and 4Crespectively show the XZ cross section, the YZ cross section and the second surface S2of the wafer1after formation of the film2on the wafer1and after modification of the film2. In the present embodiment, regions2aof the film2are irradiated with plasma so that the film2is partially modified within the regions2a. Hereinafter, the regions2aare referred to as “modified regions2a”. The modified regions2aof the present embodiment are modified so as to apply tensile stress to the wafer1. Since the modified regions2aof the present embodiment are processed so as to each have a band-like shape extending in the Y direction, the modified regions2aapply, to the wafer1, tensile stress mainly in the Y direction. The tensile stress is applied to the wafer1so as to contract the second surface S2mainly in the Y direction. Accordingly, while the upwardly projected warpage is inhibited by the film2(FIG. 4A), the downwardly projected warpage is also inhibited by the film2(FIG. 4B).

As described above, according to the present embodiment, the warpage of the wafer1in the X direction and the warpage of the wafer1in the Y direction can be independently inhibited by partial modification of the film2. Therefore, even in a case where the wafer1is warped into a complicated shape, such as a case where the wafer1is warped into an upwardly projected shape along the X direction, and is warped into a downwardly projected shape along the Y direction, the warpage of the wafer1can be sufficiently inhibited. The warpage of the wafer1may cause problems such as an error in conveyance of the wafer1, contact between the wafers1, contact between the wafer1and the substrate treatment apparatus, misalignment relative to the wafer1in lithography, abnormal discharge in the substrate treatment apparatus, and the like. However, according to the present embodiment, these problems can be reduced.

InFIGS. 4A to 4C, the film2is modified with plasma so as to have the modified regions2aeach having a band-like shape extending in the Y direction and the remaining regions having not been modified with the plasma and having shapes surrounding the modified regions2a. When the film2is modified by oxidation or nitriding, each of the former regions (modified regions2a) is an example of the first region having a first film quality, and each of the latter regions (remaining regions) is an example of the second region having a second film quality. The modified regions2aof the film2apply, to the wafer1, tensile stress mainly in the Y direction such that the wafer1is inhibited from being warped into a downwardly projected shape mainly along the Y direction. In contrast, the remaining regions of the film2apply, to the wafer1, compressive stress in the X direction and the like such that the wafer1is inhibited from being warped into an upwardly projected shape along the X direction and the like. Each of the modified regions2ais sandwiched between portions of the remaining regions.

Modification of the film2may be implemented by partial reduction or partial increase of the thickness of the film2. In this case, the thickness of each of the modified regions2ais reduced by partial reduction of the thickness of the film2, or is increased by partial increase of the thickness of the film2. In this case, each of the modified regions2ais an example of the first region having a first film thickness, and each of the remaining regions is an example of a second region having a second film thickness. The partial reduction of the film2is implemented by partially etching of the film2, for example. The partial increase of the thickness of the film2is implemented by partial deposition of a new film on the film2, for example.

In the present embodiment, the film2is scanned with plasma in the Y direction, so that the modified regions2aeach having a band-like shape extending in the Y direction are formed. The modified regions2amay be formed by preparation of a mask including band-like openings extending in the Y direction, and by supply of plasma to the film2via the mask. Alternatively, the modified regions2amay be formed by use of a technique other than plasma irradiation, as described later.

In irradiation of the film2with plasma, the plasma irradiation position or the plasma irradiation condition can be determined in accordance with the shape of the warpage of the wafer1, for example. Examples of the plasma irradiation position include the coordinates or lengths of the modified regions2a. Examples of the plasma irradiation condition include a plasma irradiation time, a plasma power (W), a plasma frequency (Hz), and the type, flow rate, and components of gas for generating plasma. For example, when the downward warpage is large, the length of each of the modified regions2amay be increased or the intensity of the plasma may be increased, such that tensile stress to the modified regions2ais increased. Accordingly, the warpage of the wafer1can be efficiently inhibited.

Measurement of the warpage of the wafer1may be carried out only before the plasma irradiation, or may be additionally carried out during the plasma irradiation. In the former case, measurement of the warpage of the wafer1may be carried out by the warpage measurement instrument12after the wafer1is mounted on the wafer holder11, as shown inFIG. 1, or may be carried out by another warpage measurement instrument before the wafer1is mounted on the wafer holder11. For example, a warpage measurement instrument external to the substrate treatment apparatus may measure the warpage of the wafer1, and may provide the measurement result to the controller14. On the other hand, in the latter case, the controller14may change the plasma irradiation position or the plasma irradiation condition, as needed, on the basis of the temporal change in the warpage of the wafer1.

Examples of the modification of the film2include oxidizing the film2, nitriding the film2, and making the film2porous. For example, the film2which is a silicon oxide film may be partially nitrided, the film2which is a silicon nitride film may be partially oxidized, the film2which is a silicon film may be partially oxidized, nitrided, or made porous, or the film2which is a metal film may be partially oxidized. However, the modification method of the film2is not limited to these examples. For example, the film2may be partially removed by plasma irradiation, or the thickness of the film2may be increased.

The shape of each of the modified regions2amay be a shape other than the aforementioned shape. Also, the film2may further have a modified region having a film quality different from those of the modified regions2a. A specific example of the film2in this case is described later.

FIG. 5is a cross-sectional view schematically showing a configuration of a semiconductor manufacturing system of the first embodiment.

FIG. 5shows a deposition apparatus21that deposits (forms) the film2on the wafer1, and a modification apparatus22that partially modifies the film2. The substrate treatment apparatus inFIG. 1corresponds to one example of the modification apparatus22. Formation and modification of the film2of the present embodiment are accordingly carried out in different apparatuses, but may be carried out in the same apparatus.

In the present system, the warpage of the wafer1is inhibited by the film2formed for the purpose of inhibiting the warpage of the wafer1. However, the warpage of the wafer1may be inhibited by the film2formed for another purpose. For example, the films2may be formed on the first surface S1and the second surface S2of the wafer1for the purpose of forming a device on the first surface S1of the wafer1, and the film2formed on the second surface S2may be reused in order to inhibit the warpage of the wafer1.

FIG. 6is a diagram for explaining a wafer treatment method of a modification of the first embodiment.

The film2of the present modification has the modified regions2ahaving been modified with plasma and each having a band-like shape extending in the Y direction, modified regions2bhaving been modified with plasma and each having a band-like shape extending in the X direction, and the remaining regions having shapes surrounding the modified regions2a,2b. Each of the modified regions2a,2bis sandwiched between portions of the remaining regions.

The film2of the present modification having not been modified is a neutral film, and applies no stress to the wafer1. On the other hand, the modified regions2aof the present modification are modified so as to apply tensile stress to the wafer1. Since the modified regions2aof the present modification are processed so as to each have a band-like shape extending in the Y direction, the modified regions2aapply, to the wafer1, tensile stress in the Y direction. Furthermore, the modified regions2bof the present modification are modified so as to apply compressive stress to the wafer1. Since the modified regions2bof the present modification are processed so as to each have a band-like shape extending in the X direction, the modified regions2bapply, to the wafer1, compressive stress mainly in the X direction.

As a result, the modified regions2aapply, to the wafer1, tensile stress mainly in the Y direction such that the wafer1is inhibited from being warped into a downwardly projected shape mainly along the Y direction. The modified regions2bapply, to the wafer1, compressive stress in the X direction such that the wafer1is inhibited from being warped into an upwardly projected shape along the X direction. Consequently, also in the present modification, the warpage shown inFIGS. 4A to 4Ccan be inhibited. Each of the former regions (modified regions2a) is an example of the first region having the first film quality. Each of the latter regions (modified regions2b) is an example of the second region having the second film quality.

In a case where the film2of the present modification is modified by the substrate treatment apparatus inFIG. 1, first plasma irradiation of forming the modified regions2aof the film2is carried out, and then, second plasma irradiation of forming the modified regions2bof the film2is carried out, for example. However, the order of carrying out the first plasma irradiation and the second plasma irradiation may be changed.

As described above, in the present embodiment, the film2provided on the wafer1is partially modified, whereby the warpage of the wafer1is inhibited. Therefore, according to the present embodiment, for example, appropriate stress is applied to the wafer1from the film2, whereby the warpage of the wafer1can be appropriately inhibited.

Second Embodiment

FIG. 7is a cross-sectional view schematically showing a configuration of a substrate treatment apparatus of a second embodiment.

A substrate treatment apparatus inFIG. 7includes a metal member holder15that holds a metal member16, in place of the plasma irradiator13.

The metal member holder15brings the metal member16formed of predetermined metal into contact with the film2. Accordingly, the film2can be partially modified, and stress being applied to the wafer1from the film2can be changed. Specifically, the film2in contact with the metal member16is partially modified. As a result, the warpage of the wafer1can be changed, as in the first embodiment. The film2in the present embodiment is, for example, an amorphous silicon film. Examples of the metal member16include a noble metal member formed of noble metal.FIG. 7shows a metal member holding arm constituting the metal member holder15.

The controller14controls operation of the metal member holder15in accordance with the measurement result of the warpage of the wafer1outputted from the warpage measurement instrument12. Under control by the controller14, the metal member holder15brings the metal member16into contact with the film2, and scans the film2by means of the metal member16, thereby partially modifies the film2. An arrow A2indicates that the metal member holding arm horizontally moves the metal member16in contact with the film2so that the film2is scanned by means of the metal member16. An arrow B2indicates that the metal member holding arm vertically moves the metal member16so as to bring the metal member16into contact with the film2or separate the metal member16from the film2. As in the plasma irradiation, the controller14determines the contact position and the contact condition of the metal member16in accordance with the measurement result of the warpage of the wafer1, and controls the operation of the metal member holder15in accordance with the determined contact position and the determined contact condition. As a result, the film2is partially modified. Examples of the contact position include the coordinates or the lengths of the modified regions. Examples of the contact conditions include the movement speed of the metal member16.

The shapes and the like of the modified regions are similar to those of the modified regions2a,2bof the first embodiment. According to the present embodiment, the warpage can be appropriately inhibited, as in the first embodiment, by modification of the film2with use of the metal member16.

Examples of the modification of the present embodiment include making the film2porous. Modification of the film2with use of the metal member16is carried out in gas or in liquid, for example. The substrate treatment apparatus inFIG. 7includes a nozzle17for supplying this gas or this liquid to the film2. The operation of the nozzle17is controlled by the controller14. The nozzle17is an example of a supplier.