JP6012998B2 - Plasma processing method - Google Patents

Description

Embodiments of the present invention relates to a plasma processing method.

  In the process of manufacturing semiconductor devices such as LSIs and transistors, a bonded substrate is used in which a device forming substrate on which a device region that operates as a device is formed and a support substrate that supports the device forming substrate are bonded with an adhesive. Various processes are performed on the surface of the device fabrication substrate from the joined state. For example, there is a process of forming a through electrode by etching a substrate using a resist mask (see, for example, Patent Document 1).

Hereinafter, a process of forming a conventional through electrode on the bonding substrate will be described.
4 and 5 are schematic views illustrating a conventional plasma processing method.
First, the device creation substrate 202 on which the device region 204 that actually operates as a device is formed and the support substrate 200 are bonded together by the adhesive layer 201 using a bonding apparatus or the like.

  Next, a hard mask layer 203 is deposited on the device fabrication substrate (FIG. 4A). Subsequently, after applying a photoresist on the hard mask layer 203, a first resist layer 205 having an opening 205a in a region corresponding to the contact hole 206 formation portion is formed through exposure and development processing (FIG. 4B). )).

  Next, the hard mask layer 203 is etched by a dry etching method using the first resist layer 205 as a mask to form an opening 203a of the hard mask layer. At this time, the surface of the device forming substrate 202 is exposed from the opening 203a of the hard mask layer (FIG. 4C).

  Next, the first resist layer 205 formed on the hard mask layer 203 is removed by dry ashing (FIG. 4D).

  Next, the device forming substrate 202 is etched by dry etching using the hard mask layer 203 as a mask to form an opening of the device forming substrate 202. This opening serves as a contact hole 206 for embedding a device electrode 204 formed under the device forming substrate 202 and a through electrode for conducting a device region (not shown) formed thereabove.

  Next, the entire surface of the hard mask layer 203 is removed by dry etching.

  Next, a barrier metal layer 207 is generated by sputtering so as to cover the side walls and bottom surface of the contact hole 206 and the surface of the device manufacturing substrate 202 (FIG. 5E).

  Next, a resist for metal generation is applied, and a second resist layer 208 having an opening in a region corresponding to the electrode formation portion is formed through exposure and development processing (FIG. 5F).

  Next, the inside of the contact hole 206 is filled with a conductive material by electroplating, and the through electrode 209 is formed so as to cover a part of the surface of the device manufacturing substrate 202 (FIG. 5G).

Next, the second resist layer 208 is removed by dry ashing (FIG. 5H).
As described above, a bonded substrate having the through electrode 209 can be generated.

However, the conventional manufacturing method described above has the following problems. That is, as shown in FIG. 4D and FIG. 5H, in the step of dry ashing the resist layer, the exposed portion (side wall and the like) of the adhesive layer 201, which is an organic material , is also eroded as in the resist. There was a problem that the eroded portion 20 was generated. When the adhesive layer 201 is eroded, it does not serve as a bonded substrate and becomes a defective product.

JP 2009-295859 A

Provided is a plasma processing method for improving productivity in a bonded substrate by suppressing the occurrence of erosion of an adhesive layer in a resist removing process on a substrate bonded by an adhesive.

According to the plasma processing method of the present invention, a step of carrying a bonded substrate obtained by bonding a device creation substrate and a support substrate with an adhesive layer into a processing container;
Forming a protective layer on the periphery of the adhesive layer by a plasma product generated in the plasma generation region;
Forming a resist layer on the substrate;
Processing the substrate using the resist layer as a mask;
Removing the resist layer used as the mask ;
A plasma processing method is provided.

  In the resist removing process of the substrates bonded by the adhesive layer, the occurrence of erosion of the adhesive layer can be suppressed and the productivity in the bonded substrate can be improved.

Schematic illustrating the plasma processing method according to the present invention Schematic illustrating the plasma processing method according to the present invention Schematic diagram illustrating a plasma processing apparatus according to the present invention. Schematic diagram illustrating a conventional plasma processing method Schematic diagram illustrating a conventional plasma processing method

[First Embodiment]
The plasma processing method according to the present invention will be described below.
1 and 2 are schematic views illustrating a plasma processing method according to the present invention.

  First, the device creation substrate 202 on which the device region 204 that actually operates as a device is created and the support substrate 200 are bonded together by the adhesive layer 201 using a bonding apparatus or the like.

  Here, when the adhesive layer 201 protrudes from the end portion of the bonded substrate, the portion protruding by dry ashing is removed. The ashing gas can be, for example, a gas in which oxygen and a gas containing fluorine are mixed.

  Next, a hard mask layer 203 is deposited on the device fabrication substrate (FIG. 1A). The hard mask layer 203 can be an oxide film such as alumina (SiO 2) which is an insulating material.

  Next, the protective layer 21 made of a material different from the resist is formed on the exposed surface (for example, the side surface) of the adhesive layer 201. That is, the protective layer 21 is formed by forming a fluorinated layer on the exposed surface of the adhesive layer 201 by performing plasma treatment on the exposed surface of the adhesive layer 201 on the end surface of the substrate. In this case, the process gas can be a gas in which oxygen is mixed with a gas containing fluorine.

According to the knowledge of the present inventor, by using a gas containing fluorine such as CF _{4 at} a ratio of 70% of the total flow rate of the process gas, CH ₂ F ₂ or NF ₃ , the adhesive layer 201 is used. It is possible to form the protective layer 21 that is a fluorinated layer on the exposed surface of the film. Thus, by forming the protective layer 21, even if the first resist layer 205 and the adhesive layer 201 are the same material, the exposed surface of the adhesive layer 201 is protected by the protective layer 21, It is possible to prevent the adhesive layer 201 from being eroded during the resist layer removing process.

  In addition, the substrate S is a laminate in which the device creation substrate 202, the adhesive layer 201, and the support substrate 200 are made of different materials, and the expansion coefficient is different, which causes peeling of the adhesive layer 201 and cracking of the substrate S. May end up. In consideration of this, the adhesive is peeled off by performing processing while controlling the temperature of the mounting table on which the substrate S is mounted so that the temperature of the substrate S is low (for example, 15 ° C. to 120 ° C.). And cracking of the substrate can be prevented.

  Subsequently, after applying a photoresist on the hard mask layer 203, a first resist layer 205 having an opening 205a in a region corresponding to the contact hole 206 formation portion is formed through exposure and development processing (FIG. 1B). )).

  Next, the hard mask layer 203 is etched by a dry etching method using the first resist layer 205 as a mask to form an opening 203a of the hard mask layer (FIG. 1C). At this time, the surface of the device forming substrate 202 is exposed from the opening 203a of the hard mask layer.

  Next, the first resist layer 205 formed on the hard mask layer 203 is removed by dry ashing (FIG. 1D).

  Next, the device forming substrate 202 is etched by dry etching using the hard mask layer 203 as a mask to form an opening of the device forming substrate 202. This opening serves as a contact hole 206 for embedding a through electrode for electrically connecting a device region 204 formed in the lower part of the device manufacturing substrate 202 and a device region (not shown) formed in the upper part.

  Next, the entire surface of the hard mask layer 203 is removed by dry etching.

  Next, a barrier metal layer 207 is generated by sputtering so as to cover the side walls and bottom surface of the contact hole 206 and the surface of the device manufacturing substrate 202 (FIG. 2E). The barrier metal layer 207 can be made of a conductive material such as Ti / Cu.

  Next, a resist for metal generation is applied, and a second resist layer 208 having an opening in a region corresponding to the electrode formation portion is formed through exposure and development processing (FIG. 2F).

  Next, a through electrode 209 is formed so as to fill the inside of the contact hole 206 by an electroplating method and cover a part of the surface of the device manufacturing substrate 202 (FIG. 2G). The through electrode 209 can be made of a conductive material such as Cu, for example.

Next, the second resist layer 208 is removed by dry ashing (FIG. 2H).
As described above, a bonded substrate having the through electrode 209 can be generated.

Thus, in the plasma processing method according to the present invention, by forming the protective layer 21 made of a material different from the resist on the adhesive exposed surface, the adhesive layer 201 is removed from the substrate bonding end surface when the resist is removed. Erosion toward the inside can be suppressed. As a result, productivity in the bonded substrate can be improved.
[Second Embodiment]
Hereinafter, the second embodiment will be illustrated with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.

  Here, a plasma processing apparatus that can be used when manufacturing a semiconductor device is illustrated.

FIG. 3 is a schematic cross-sectional view for illustrating the plasma processing apparatus according to the second embodiment. A plasma processing apparatus 100 shown in FIG. 3 is a plasma processing apparatus generally called a remote plasma processing apparatus in which a plasma generation region is isolated from a processing container. The plasma processing apparatus 100 is used as a processing apparatus that performs plasma processing for forming the protective layer 21 and plasma processing for removing the resist layer by ashing.

The plasma processing apparatus 100 includes a processing container 1, a gas supply unit 2, a plasma generation unit 3, and a decompression unit 8. The plasma generator 3 is provided with a discharge tube 7, a microwave generator 10, an introduction waveguide 6 and the like.

The processing container 1 is a sealed container so that a reduced pressure atmosphere can be maintained. The bonded substrate S obtained by bonding the device forming substrate 202 and the support substrate 200 with the adhesive layer 201 is placed on a mounting table provided in the processing container 1 and plasma generated by plasma generated in the plasma generation region P. Ashing is performed by the product. The mounting table incorporates the temperature control means 4a and can control the temperature of the substrate S.

  A loading / unloading exit 9 for loading / unloading the substrate S into / from the processing container 1 is provided on the side wall of the processing container 1. A gate valve 9 a is provided at the carry-in / out port 9. The gate valve 9a has a door 9b, and opens / closes the loading / unloading port 9 by opening / closing the door 9b by a gate opening / closing mechanism (not shown). The door 9b is provided with a sealing member 9c such as an O-ring. When the loading / unloading port 9 is closed by the door 9b, the contact surface between the loading / unloading port 9 and the door 9b can be sealed.

  An exhaust port 8a is provided near the bottom in the processing container 1, and is connected to the decompression unit 8 via a pressure control unit 8b. The decompression unit 8 evacuates while controlling the pressure in the processing container 1 by the pressure control unit 8b, and decompresses until the pressure inside the processing container 1 becomes a predetermined pressure.

  A discharge tube 7 having a plasma generation region inside is connected to a processing vessel via a gas transfer unit 5. The gas transfer unit 5 communicates with the processing container at a position where the plasma product generated in the plasma generation region P can reach the main surface of the substrate S.

The gas supply unit 2 includes a first gas supply unit 2a, a second gas supply unit 2b, and a gas mixing unit 5a. The first gas supply means 2a supplies a first processing gas G1 (for example, CF ₄ , CH ₂ F ₂ , NF ₃ ) containing fluorine. The second gas supply means 2b supplies a second processing gas G2 containing oxygen gas.

  The gas mixing unit mixes the first processing gas G1 and the second processing gas G2 at a predetermined ratio according to the processing step via the MFC (mass flow controller).

For example, in the case of the process of forming the protective layer 21 on the exposed surface of the adhesive layer 201, the gas mixing unit uses the first processing gas G1, so as to be a gas that forms the fluorinated protective layer 21. The second processing gas G2 is mixed. For example, when the first processing gas G1 is CF ₄ , the gas is mixed so that the first processing gas G1 is 70% or more with respect to the total flow rate of the mixed gas with the second processing gas G2. . When the first processing gas is CH ₂ F ₂ or NF ₃ , the first processing gas G1 is 30% or more with respect to the total flow rate of the mixed gas with the second processing gas G2. Mix the gas.

  In the process of removing the resist on the device manufacturing substrate 202, the gas mixing unit mixes the gases so that the gas supplied from the second processing gas G2 is a main component. For example, the gases are mixed so that the first processing gas G1 is about 8%.

  As described above, the mixed gas mixed in the gas mixing unit 5 a is introduced into the plasma generation region P inside the discharge tube 7.

  The microwave generation unit 10 oscillates a microwave M having a predetermined power (eg, 2.45 GHz) and radiates it to the introduction waveguide 6.

  The introduction waveguide 6 propagates the microwave M radiated from the microwave generator 10 and introduces the microwave M into the plasma generation region P inside the discharge tube 7. Energy is given by the introduced microwave M, and plasma of the processing gas G is formed in the plasma generation region P. Active species such as radicals contained in the plasma are supplied onto the substrate S in the processing container via the gas transfer unit 5, and the ashing process of the resist layer is performed.

  As described above, in the plasma processing apparatus according to the present invention, the protective layer 21 made of a material different from the resist is formed on the exposed surface of the adhesive so that the adhesive layer 201 can be removed from the end surface of the substrate bonding when the resist is removed. Erosion toward the inside can be suppressed. As a result, productivity in the bonded substrate can be improved.

  The embodiment has been illustrated above. However, the present invention is not limited to these descriptions.

  Regarding the above-described embodiment, those in which those skilled in the art appropriately added, deleted, or changed the design, or added the process, omitted, or changed the conditions also have the features of the present invention. As long as it is within the scope of the present invention.

  For example, although a remote plasma type plasma processing apparatus has been described as an example of the plasma processing apparatus of the present embodiment, the plasma generation region and the reaction chamber in which the substrate S is placed are provided in the same processing container. The present invention can also be applied to other types of plasma processing apparatuses such as a downflow type. However, as described above, the plasma generation region and the substrate are separated in order to prevent the peeling of the adhesive and the cracking of the substrate from occurring due to the difference in the expansion coefficient of each of the bonded substrates and the adhesive. In addition, it is preferable to perform processing with a remote plasma processing apparatus in which the temperature of the substrate is not easily affected by the heat radiation of the plasma.

  Further, in the embodiment of the present invention, the step of forming the protective layer 21 is performed after the device forming substrate 202 and the support substrate 200 are bonded together and the hard mask layer 203 is deposited on the device forming substrate. Although explained, it is not limited to this. For example, the bonding may be performed after the device forming substrate 202 and the support substrate 200 are bonded and before the hard mask layer 203 is deposited.

  However, as in this embodiment, by introducing a gas for forming the protective layer 21 after the hard mask layer 203 is deposited, the hard mask layer 203 becomes a mask, and the protective layer is formed on the surface of the device manufacturing substrate 202. It is possible to prevent the gas forming the gas 21 from adhering. As a result, it can be suppressed that the surface of the device creation substrate is fluorinated and becomes a particle source in a later step.

  In addition, when a gas for forming a protective layer is introduced after the first resist layer 205 or the second resist layer 208 is formed, the protective layer is also formed on the surfaces of the first and second resist layers, Since removal of the resist becomes difficult, it is preferable to introduce a gas for forming a protective layer before the resist is formed.

  As described above, the elements included in each of the above-described embodiments can be combined as much as possible, and combinations thereof are also included in the scope of the present invention as long as they include the features of the present invention.

DESCRIPTION OF SYMBOLS 1 Processing container 2 Gas supply part 2a 1st gas supply means 2b 2nd gas supply means 3 Plasma generation part 4 Mounting base 4a Temperature control means 5 Gas conveyance part 5a Gas mixing part 6 Introducing waveguide 7 Discharge tube 8 Depressurization Part 8a Exhaust port 8b Pressure control part 9 Loading / unloading exit 9a Gate valve 9b Door 9c Sealing member 10 Microwave generation part 15 Control part 20 Erosion part 21 Protective layer 200 Support substrate 201 Adhesive layer 202 Device creation board 203 Hard mask Layer 203a hard mask layer opening 204 device region 205 first resist layer 205a first resist layer opening 206 contact hole 207 barrier metal layer 208 second resist layer 209 through electrode S substrate P plasma generation region G1 first 1 processing gas G2 1st processing gas M microwave

Claims (4)

A step of carrying a bonded substrate obtained by bonding a device creation substrate and a support substrate with an adhesive layer into a processing container;
Forming a protective layer on the periphery of the adhesive layer by a plasma product generated in the plasma generation region;
Forming a resist layer on the substrate;
Processing the substrate using the resist layer as a mask;
Removing the resist layer used as the mask;
A plasma processing method comprising:   2. The plasma processing method according to claim 1, further comprising a step of removing the adhesive protruding from the substrate when the substrates are bonded before the step of forming a protective layer on the periphery of the adhesive layer.   The plasma processing method according to claim 1, wherein a processing gas used in the step of forming the protective layer is a gas containing fluorine. A plasma processing method including a step of removing a resist layer formed on a bonding substrate in which a device creation substrate and a support substrate are bonded by an adhesive layer by supplying active species generated by plasma,
In the step of removing the resist layer, by removing the resist layer on the bonding substrate in which a protective layer made of a material different from the resist layer formed by plasma treatment is formed on the periphery of the adhesive layer. The plasma processing method is characterized in that the adhesive layer is prevented from being eroded inward from the substrate bonding end face.

Images