JP6604595B2 - Plasma processing apparatus and plasma processing method - Google Patents

Description

  The present invention relates to an apparatus and method for etching a surface of an object to be processed with plasma.

  In various processes for manufacturing electronic components and circuit boards, a plasma processing apparatus that generates plasma in a processing chamber and etches the surface of an object to be processed is used. In order to improve productivity, a plurality of plasma processing apparatuses (general machines) may be operated in parallel in one process of performing plasma processing. However, even if a plurality of general machines having the same structure are operated under the same conditions, their etching rates may be different from each other.

  Therefore, Patent Document 1 describes the relationship between the intensity of plasma and all control parameters in the plasma process between a general machine and a plasma processing apparatus (reference apparatus) that has the same structure as the general machine and serves as a calibration reference. And, based on the reference device, teach that the processing conditions are calibrated during the plasma processing of the general machine. Patent Document 2 teaches that data that can grasp the plasma state is acquired using a reference device, a parameter to be calibrated is specified, and then a parameter of a general machine corresponding to the specified parameter is calibrated. Thereby, since the parameter to calibrate decreases, the time which a calibration requires is shortened.

JP 2002-270581 A JP 2009-295658 A

  However, in the above method, the etching rate may be different between the reference apparatus and the general machine and between a plurality of general machines.

  One aspect of the present invention includes a processing chamber, an electrode provided in the processing chamber, and a high-frequency power source that generates plasma in the processing chamber by applying a first high-frequency power to the electrode. A plasma processing apparatus for mounting a processing object on the electrode unit and etching the surface of the processing object, and further using the plasma processing apparatus, in advance with respect to the first standard sample A first database showing the relationship between the first high-frequency power and the first etching rate acquired by the executed plasma processing, and a reference plasma processing having the same structure as the plasma processing apparatus and serving as a calibration reference A second high frequency power and a second etching rate obtained by a plasma process performed in advance on a second standard sample having the same composition as the first standard sample using the apparatus. A storage unit that holds the second database indicating the relationship between the process recipe and the recipe designated power that is the high frequency power designated in the process recipe, and the recipe designated power is read from the second database. A reference device conversion rate that is the second etching rate at the same second high-frequency power is calculated, and the first etching rate at the same first etching rate as the reference device conversion rate is calculated from the first database. A plasma processing apparatus, comprising: a calculation unit that calculates correction power that is high-frequency power; and a control unit that corrects the recipe-designated power specified by the process recipe to the correction power calculated by the calculation unit. .

  Another aspect of the present invention includes a processing chamber, an electrode portion provided in the processing chamber, and a high-frequency power source that generates plasma in the processing chamber by applying a first high-frequency power to the electrode portion. A plasma processing method for etching a surface of a processing object placed on the electrode unit using a plasma processing apparatus including a storage unit that holds a process recipe, and the storage unit further includes: A first database showing a relationship between the first high-frequency power and the first etching rate, which is obtained by a plasma process performed in advance on a first standard sample using a plasma processing apparatus; Using a reference plasma processing apparatus having the same structure as the plasma processing apparatus and serving as a calibration reference, a pre-executed process is performed on a second standard sample containing the same composition as the first standard sample. A second database indicating the relationship between the second high-frequency power and the second etching rate, which is acquired by the process, and stores the recipe-designated power that is the high-frequency power designated in the process recipe. Read, calculate from the second database a reference device conversion speed that is the second etching speed at the second high frequency power that is the same as the recipe specified power, and convert the reference device conversion from the first database. A calculation step of calculating a correction power that is the first high-frequency power at the first etching rate that is the same as a velocity, and the correction power calculated in the calculation step by using the recipe-specified power specified in the process recipe. And a correction step of correcting to a plasma processing method.

  According to the present invention, the variation in the etching rate between the reference device and the general machine and between the plurality of general machines is suppressed by a very simple method.

It is a conceptual diagram which shows the schematic structure of the plasma processing apparatus which concerns on embodiment of this invention in a cross section. It is a flowchart explaining the process of the plasma processing which concerns on embodiment of this invention. It is a graph which shows notionally the information which the 1st database concerning the embodiment of the present invention holds. It is a graph which shows notionally the information which the 2nd database concerning the embodiment of the present invention holds. It is a flowchart explaining the process of the plasma processing which concerns on other embodiment of this invention.

(Plasma processing equipment)
The plasma processing apparatus includes a processing chamber, an electrode unit that is provided in the processing chamber and on which a processing target is placed, and a high-frequency power source unit that applies a first high-frequency power to the electrode unit. When a plasma generating gas is supplied to the processing chamber and the first high frequency power is applied to the electrode portion, plasma is generated in the processing chamber. The surface of the processing object placed on the electrode part is etched by the generated plasma.

  The depth of etching of the object to be processed is determined by the etching rate and the processing time. The etching rate is controlled by various parameters such as high-frequency power (first high-frequency power) applied to the electrode section, the type and concentration of the plasma generating gas, and the pressure in the processing chamber. For this reason, in Patent Documents 1 and 2, a large number of data relating to the above parameters is acquired using various measuring devices provided in a general machine, and the state of plasma processing being performed in the general machine is grasped. Then, various data in the general machine are corrected in real time based on the corresponding data of the plasma processing apparatus (reference apparatus) serving as a reference for calibration, thereby bringing the state of the plasma processing being executed in the general machine closer to the reference apparatus. ing. However, even when the parameters of the general machine are corrected in this way, the etching rate varies among plasma processing apparatuses (including the general machine and the reference apparatus), and the etching depth varies. Variations in the etching rate between plasma processing apparatuses occur because the etching rate is a parameter other than the above, for example, the difference in assembly state of the components of each plasma processing apparatus, or a slight difference in dimensions within design tolerances, Alternatively, it is considered that this is due to the influence of parameters unique to each plasma processing apparatus such as a difference in the degree of wear of components in the processing chamber due to a difference in plasma processing history.

  Therefore, in the present embodiment, the first etching rate under a predetermined condition acquired in advance using a general machine, and the second etching rate under the same conditions as the general machine acquired in advance using a reference apparatus. Based on the above, the plasma processing conditions of the general machine are corrected. The first etching rate and the second etching rate are calculated from the etching depth actually processed by the general machine and the reference apparatus and the application time of the high frequency power under a predetermined condition. That is, the first and second etching rates are calculated based on the actually measured values. Therefore, the first and second etching rates reflect parameters unique to each plasma processing apparatus in addition to various parameters related to the plasma processing state as used in Patent Document 1 or 2. Thus, by using the measured value of the etching rate for correction of the plasma processing conditions, it is difficult to eliminate by correction using various parameters related to the conventional plasma processing state. Variations caused by parameters can be eliminated. Therefore, when there are a plurality of general machines between the reference device and the general machines, the variation in the etching rate among the general machines is further suppressed. Therefore, even if there are a plurality of general machines, any general machine can perform plasma processing equivalent to that of the reference apparatus.

  Further, the plasma processing conditions of the general machine are corrected only for the first high-frequency power applied to the electrode unit of the general machine. When the parameters such as the type and concentration of the plasma generating gas and the pressure in the processing chamber are the same, the etching rate greatly depends on the high frequency power applied to the electrode portion. Therefore, only the first high-frequency power is corrected without changing other conditions that affect the etching rate. Thereby, process management at the production site becomes very easy.

  Hereinafter, a plasma processing apparatus 100 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a conceptual diagram showing a schematic structure of a plasma processing apparatus according to an embodiment of the present invention in cross section.

  The processing chamber 103 a is formed by sealing the vacuum chamber 103 including the horizontal base portion 101 and the lid portion 102. The lid portion 102 is disposed so as to be movable up and down by an elevating means (not shown). When the lid 102 is lowered and comes into contact with the upper surface of the base 101, the vacuum chamber 103 is hermetically sealed. At this time, the sealing member 104 is interposed between the lid portion 102 and the base portion 101, thereby ensuring the sealed state of the processing chamber 103 a. In the processing chamber 103a, the processing target 109 is subjected to plasma processing. The base 101 is provided with an opening 101a, and an electrode 105 is fitted through an insulating member 106 so as to close the opening 101a. The upper surface of the electrode part 105 is covered with an insulating layer 107. A guide member 108 for positioning the processing object 109 is disposed on the upper surface of the insulating layer 107.

  A through hole 101b is formed at the periphery of the opening 101a of the base 101. A pipe line 111 is inserted into the through hole 101 b, and a vent valve 112, a gas supply valve 113, a vacuum valve 114, and a vacuum gauge 115 are connected to the pipe line 111. A gas supply unit 116 and a vacuum pump 117 are further connected to the gas supply valve 113 and the vacuum valve 114, respectively. When the vacuum valve 114 is opened and the vacuum pump 117 is operated, the gas in the processing chamber 103a is discharged and the pressure is reduced. The degree of vacuum in the processing chamber 103 a is measured by a vacuum gauge 115. On the other hand, when the gas supply valve 113 is opened, the plasma generating gas is supplied from the gas supply unit 116 into the processing chamber 103a. The gas supply unit 116 has a built-in flow rate adjusting function, and the flow rate of the plasma generating gas supplied into the processing chamber 103a is adjusted. When the vent valve 112 is opened, the atmosphere is supplied into the processing chamber 103a.

  A high frequency power supply unit 119 is electrically connected to the electrode unit 105 via a matching unit 118. On the other hand, the lid portion 102 is grounded to the ground portion 110. When the plasma generating gas is supplied into the processing chamber 103 a and the high frequency power supply unit 119 is operated, a high frequency voltage is applied between the electrode unit 105 and the lid unit 102. Thereby, plasma is generated in the processing chamber 103a. The matching unit 118 matches the impedance of a plasma discharge circuit (not shown) that generates plasma and the high-frequency power supply unit 119. The vent valve 112, the gas supply valve 113, the vacuum valve 114, the vacuum gauge 115, the gas supply unit 116, the vacuum pump 117, and the high frequency power supply unit 119 are controlled by the control unit 120.

  Furthermore, an input unit 121, a correction selection unit 122, a storage unit 123, a calculation unit 124, and a display unit 125 are connected to the control unit 120. The input unit 121 receives a process recipe and data for creating the first and second databases. The correction selection unit 122 includes, for example, a changeover switch. The operator can select whether or not to correct the process recipe by switching this switch. The correction selection unit 122 is not limited to the mechanical switch as described above. For example, the correction selection unit 122 may be operated by inputting whether or not to correct the process recipe to the input unit 121.

Each data for creating a database input to the input unit 121 is stored in the storage unit 123 as a first or second database. The process recipe input to the input unit 121 is also stored in the storage unit 123. When the correction selection unit 122 has selected to correct the process recipe, the calculation unit 124 performs a calculation to correct the high-frequency power (recipe specified power P ₀ ) specified in the process recipe based on each database. The corrected first high-frequency power (corrected power P ₁ ) is calculated, and the result is transmitted to the control unit 120. The control unit 120 corrects the recipe specified power P ₀ specified in the process recipe to the corrected power P ₁ and instructs each of the above units to start the plasma processing according to the corrected process recipe. The display unit 125 displays the input process recipe, the first and second databases, an error message indicating that an error has been notified from the calculation unit 124 to the control unit 120, and the like. Specific functions of the control unit 120, the input unit 121, the storage unit 123, and the calculation unit 124 will be described later.

[First Embodiment]
Hereinafter, the plasma treatment process according to the first embodiment will be described with reference to FIGS. FIG. 2 is a flowchart for explaining the steps of the plasma processing according to the present embodiment. FIG. 3 is a graph conceptually showing information held in the first database. FIG. 4 is a graph conceptually showing information held in the second database.

(Plasma treatment method)
First, an etching rate by plasma generated by a predetermined high-frequency power, which is acquired in advance using a general machine and a reference device, is input to the input unit 121 together with the high-frequency power. For example, a plurality of sets are input to the input unit 121 with the high frequency power applied to the electrode unit of the general machine and the etching rate at that time as one set. Similarly, a high frequency power applied to the electrode portion of the reference device and the etching rate at that time are set as one set, and a plurality of sets are input. The input data is stored in the storage unit 123 to create a first database and a second database, respectively (data storage step). The data storage process may be performed before or after the input process (step 1) described later.

The storage unit 123 holds a first database that holds information as shown in FIG. 3 based on the input data, for example. In the graph of FIG. 3, the horizontal axis represents the first high-frequency power, and the vertical axis represents the first etching rate. In FIG. 3, the etching rate R ₁ calculated from the etching depth and application time when four patterns of high-frequency power P ₁ are applied to the electrode part of a general machine is plotted. The number of data is not limited to four patterns. Further, the database may be configured only with data input from the input unit 121, or may include data for interpolating data input from the input unit 121. The input data is interpolated by, for example, drawing an approximate straight line or approximate curve of the input data. In this way, the relationship between the high-frequency power P ₁ measured using a general machine and the etching rate R _{1 at} that time is held in the storage unit 123 as the first database.

Furthermore, the storage unit 123, the relationship of the general machine and the second in the reference device with the same structure as the high frequency power P ₂ and the second etch rate R ₂ is, first holds the information as shown in FIG. 4, for example 2 database. The second database is obtained in the same manner as the first database except that a reference device having the same structure as that of a general machine is used.

  Data for creating each database is acquired in advance by performing plasma processing using a reference apparatus and a general machine, using the same substance as an object of etching, under processing conditions for creating a predetermined database. The database is created based on the result of plasma processing under at least one predetermined processing condition. In order to increase the accuracy of correction, it is desirable to create a database using the results of plasma processing under a plurality of processing conditions with different high-frequency power.

  It is desirable that the material to be etched when acquiring data is included in the processing object to be subjected to plasma processing by an actual general machine, and is the same as the material to be etched by the plasma (etching object). A substance having a composition is desirable. That is, the object to be processed, the sample (first standard sample) when acquiring the data of the general machine, and the sample (second standard sample) when acquiring the data of the reference device are the etching objects. It is desirable that both include substances having the same composition. The 1st standard sample and the 2nd standard sample may be formed only with an etching subject, and may contain an etching subject and other substances which are not etched on the plasma treatment conditions concerned. Further, the first standard sample and the second standard sample may have the same structure as the object to be processed.

The processing object is not particularly limited, and examples thereof include a substrate used for manufacturing an electronic device, a circuit substrate on which a circuit is formed on a substrate, a mounting substrate on which electronic components are mounted on a circuit substrate, a semiconductor substrate, and the like. It is done. The object to be etched is not particularly limited, and examples thereof include a substrate, an insulating film formed on the substrate, a resist on the substrate, a metal material for configuring a circuit, and a semiconductor material. The plasma generating gas is appropriately selected according to the object to be etched. For example, when etching gold, argon gas, when etching organic substances such as resist, oxygen gas is used, and when etching an insulating film such as SiO ₂ , a fluorocarbon-containing gas such as CF ₄ is used. it can.

  The etching rate is calculated from the application time of the high frequency power and the etching depth. The etching depth is determined by placing a standard sample on the electrode part, supplying an appropriate plasma generating gas to the object to be etched in the processing chamber, and then applying a predetermined high frequency power for a predetermined time. Measured from the sample.

  The application time is not particularly limited as long as a measurable etching depth is obtained. The application time may be the same as the application time (hereinafter referred to as processing time) actually performed in a general machine, or may be longer than the processing time. Here, since it is only necessary to know the relationship between the applied high-frequency power applied to the electrode portion and the etching rate, the application time for collecting data can be determined regardless of the actual processing time or etching depth. . For example, when the process performed by a general machine is a cleaning process, the processing time may be several seconds to several hundred seconds, and the etching depth may be on the nano-order level. It is very difficult to measure a nano-order level etching depth. However, in the acquisition of data for creating each database, the application time can be increased to such an extent that, for example, it reaches a level (for example, on the micron order) that facilitates measurement of the etching depth. Therefore, since the etching rate is calculated more accurately, variations in the etching rate among the plasma processing apparatuses are easily suppressed.

  Furthermore, as described above, the standard sample used when acquiring data only needs to include at least the etching object. Therefore, even if the actual processing object of a general machine has a complicated structure (for example, a mounting substrate) and it is difficult to measure the etching depth of the etching object, the etching rate is more accurate. Can be calculated. That is, this embodiment in which each database is created in advance is particularly effective when the actual plasma processing time is short (for example, several seconds to several hundred seconds) or when the processing target has a complicated structure. Useful. Specifically, the plasma processing apparatus 100 or the plasma processing method of the present embodiment is preferably used in the mounting substrate cleaning process.

(1) Input process In the input process, a process recipe is input to the input unit 121 (step 1). In the process recipe, conditions for performing plasma processing such as processing time, supply amount of plasma generating gas, recipe-designated power P ₀ to be applied to the electrode part of a general machine, pressure in the processing chamber 103a, and the like are specified. .

(2) Correction Selection Step Next, the correction selection unit 122 selects whether or not to correct the process recipe (step 2).

  When it is selected that the process recipe is not corrected, the control unit 120 starts the plasma processing according to the input process recipe (for example, the vent valve 112, the gas supply valve 113, the vacuum valve 114, The vacuum gauge 115, gas supply unit 116, vacuum pump 117, high frequency power supply unit 119, etc.) are instructed (step 99).

(3) Calculation Step On the other hand, when it is selected to correct the process recipe, the control unit 120 calls the second database from the storage unit 123 and corresponds to the recipe designated power P ₀ designated by the process recipe. second reading a high frequency power _{P 2} (step 3). Subsequently, a second etching rate (reference device conversion rate R ₂ ) corresponding to the second high-frequency power P ₂ is calculated from the second database (step 4, see FIG. 4). Next, the control unit 120 from the storage unit 123 calls the first database, the first of the first high-frequency power corresponding to the etching rate R ₁ corresponding to the reference device in terms rate R ₂ calculated in step 4 (Correction power P ₁ ) is calculated (step 5; see FIG. 3).

(4) Correction Step The control unit 120 corrects the recipe specified power P ₀ specified in the process recipe to the first corrected power P ₁ calculated in Step 5, and starts plasma processing according to the corrected process recipe. Instruct the above-described units of the plasma processing apparatus (step 6).

[Second Embodiment]
Hereinafter, the plasma processing steps according to the second embodiment will be described with reference to FIG. FIG. 5 is a flowchart for explaining a plasma processing step according to the present embodiment. In the present embodiment, in the calculation unit 124, the difference between the second high-frequency power P ₂ read in step 3 (that is, the recipe designated power P ₀ ) and the correction power P ₁ read in step 5 is calculated. This is the same as in the first embodiment except that it is calculated and it is determined whether or not this difference is larger than a preset threshold value (step 7: determination step).

(5) Determination process The determination process may be performed after step 5 and before step 6. As shown in FIG. 5, the difference between the corrected power P ₁ and the recipe specified power P ₀ is greater than the threshold, the error is notified to the control unit 120 from the operation unit 124 (step 999). When the error is notified, the control unit 120 determines that there is a possibility that there is an error in the first and / or second database, displays this fact on the display unit 125, and notifies the operator.

On the other hand, when the difference between the corrected power P ₁ and the recipe designated power P ₀ is equal to or smaller than the threshold, the control unit 120 uses the recipe designated power P ₀ designated in the process recipe as the corrected power P ₁ calculated in step 5. And instruct each of the above parts of the plasma processing apparatus to start plasma processing according to the corrected process recipe (step 6: correction step). The threshold value is set based on, for example, a difference in etching rate at the same high frequency power between the reference apparatus and the general machine when no correction is performed.

  According to the plasma processing apparatus and the plasma processing method of the present invention, variation in etching rate between the reference apparatus and the general machine and between a plurality of general machines is suppressed. It is suitably used for the process.

DESCRIPTION OF SYMBOLS 100: Plasma processing apparatus, 101: Base part, 101a: Opening part, 101b: Through-hole, 102: Lid part, 103: Vacuum chamber, 103a: Processing chamber, 104: Seal member, 105: Electrode part, 106: Insulating member 107: Insulating layer 108: Guide member 109: Processing object 110: Grounding part 111: Pipe line 112: Vent valve 113: Gas supply valve 114: Vacuum valve 115: Vacuum gauge 116: Gas supply unit, 117: vacuum pump, 118: matching unit, 119: high frequency power supply unit, 120: control unit, 121: input unit, 122: correction selection unit, 123: storage unit, 124: calculation unit, 125: display unit

Claims (7)

A processing chamber;
An electrode provided in the processing chamber;
A high frequency power supply unit that generates plasma in the processing chamber by applying a first high frequency power to the electrode unit,
A plasma processing apparatus for mounting a processing object on the electrode unit and etching the surface of the processing object,
further,
A first database showing a relationship between the first high-frequency power and a first etching rate, which is obtained by a plasma process performed in advance on a first standard sample using the plasma processing apparatus; Using a reference plasma processing apparatus having the same structure as that of the plasma processing apparatus and serving as a calibration reference, it is acquired by a plasma process performed in advance on a second standard sample containing the same composition as the first standard sample. A storage unit for storing a second database indicating a relationship between the second high-frequency power and the second etching rate, and a process recipe;
A recipe designated power that is a high frequency power designated in the process recipe is read out, and a reference device conversion speed that is the second etching speed at the second high frequency power that is the same as the recipe designated power is read from the second database. A calculation unit that calculates correction power that is the first high-frequency power at the first etching rate that is the same as the reference device conversion rate from the first database;
A control unit that corrects the recipe designated power designated in the process recipe to the corrected power calculated by the computing unit;
A plasma processing apparatus.   The plasma processing apparatus of Claim 1 provided with the correction | amendment selection part which selects whether the correction | amendment of the said process recipe is performed. The calculation unit further calculates a difference between the recipe designated power and the correction power,
If the difference is greater than a preset threshold,
The plasma processing apparatus according to claim 1, wherein the calculation unit notifies an error to the control unit. A processing chamber;
An electrode provided in the processing chamber;
A high-frequency power supply unit that generates plasma in the processing chamber by applying a first high-frequency power to the electrode unit;
A storage unit for holding process recipes;
A plasma processing method comprising: etching a surface of a processing object placed on the electrode unit using a plasma processing apparatus comprising:
The storage unit further uses the plasma processing apparatus to obtain a relationship between the first high-frequency power and the first etching rate acquired by plasma processing performed in advance on the first standard sample. First reference database and a second standard sample having the same structure as the plasma processing apparatus and having the same composition as the first standard sample in advance using a reference plasma processing apparatus serving as a reference for calibration A second database showing the relationship between the second high-frequency power and the second etching rate, acquired by the executed plasma treatment,
A recipe designated power that is a high frequency power designated in the process recipe is read out, and a reference device conversion speed that is the second etching speed at the second high frequency power that is the same as the recipe designated power is read from the second database. A calculating step of calculating correction power, which is the first high-frequency power at the first etching rate that is the same as the reference device conversion rate, from the first database;
A correction step of correcting the recipe specified power specified in the process recipe to the correction power calculated in the calculation step;
A plasma processing method.   The plasma processing method according to claim 4, further comprising a correction selection step of selecting whether or not to correct the process recipe before the calculation step.   6. The method according to claim 4, further comprising a determination step of calculating a difference between the recipe designated power and the correction power after the calculation step and determining whether the difference is larger than a preset threshold value. The plasma processing method as described. The plasma processing method according to any one of claims 4 to 6, wherein the processing object is a circuit board on which an electronic component is mounted.

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