TW530351B - Method for monitoring status of dry etching process - Google Patents

Abstract

A kind of method for monitoring the status of dry etching process is disclosed in the present invention. By using a time mode to perform a dry etching process onto a wafer in a dry etching apparatus, an etching time parameter and the initial value of plasma intensity are set in the dry etching process. In addition, a plasma intensity detector is used to monitor the plasma during the etching time parameter period so as to obtain a detection value curve of plasma intensity. The invention is featured with the followings. When the detection value of plasma intensity is larger than or equal to the set initial value of plasma intensity, the following process is then continuously performed. On the contrary, when the detection value of plasma intensity is smaller than the set initial value of plasma intensity, the following process is terminated and an alerting signal is sent by the dry etching apparatus. Thus, it is capable of assisting the timing-mode dry etching process in confirming whether the real plasma status is normal or not.

Description

530351 V. Description of the Invention (1) [Field of the Invention] The present invention relates to a method for dry-etching a semiconductor in a method for monitoring the dry-remaining process conditions, and is more particularly related to the use of a plasma intensity detection value to determine the dryness. Benefits of the etching process status [Known technical description] In the semi- = process, dry dry (plasma) plasma is used to perform anisotropic etching. The vertical etching rate is much higher than the horizontal neodymium etching. The design of the speed, the pattern on the mask is transferred to the film. The bee field will first control the plasma etching process of the contact hole and via via with a small cross-sectional area. The cross-sectional area is small, and the ratio of the cross-sectional area of the hole to the entire contact surface is relatively small. When the ratio of the cross-sectional area is less than 5%, the optical emission or laser interference cannot be effectively used. Endpoint detection mode such as iaser 2 terfer⑽etry to order plasma? Endpoint detection of the engraving process, because the cross-sectional area of the hole is too small to make a significant change in the gas spectrum ' It is impossible to judge whether the etching process is J, so the current industry in this case is expected to use the time mode to perform the dry etching process. However, when using the time mode to perform the dry etching process, it will still = some Trouble. For example, although an etching time parameter has been set for the dry etching process, if the plasma is not completely ignited (noignite) or the conditions of the reaction chamber are changed, it will result in a different etching process. Lost costs due to scrapped wafers. Therefore, look for a way to use time die

530351 V. Description of the invention (2) The method of Jinglaigua to control the dry etching process has become a lesson in a hurry ° The test of the first test is shown in Figure 1, which shows the schematic diagram of the conventional plasma cutting device 10 The slurry etching device i 0 includes an etching reactor i 2, and an electrode plate 14 and a lower electrode plate 16 ′ -gas input tube 20 are arranged inside the etching; an upper part of the Γ state 12 is connected, and a gas exhaust tube 22 is connected. Connected to the bottom of the etch reactor 12-The RF generator 24 is connected to the upper electrode plate 14 and controls the opening and closing of the RF generator 24. During the "X" process, a wafer 18 is placed under the etching reactor 12: on the plate U, 'electric water P is generated by the gas input by the gas input tube 20, which can The thin film deposition layer on the surface of the wafer 18 is subjected to an etching process. In addition to =, 1 ;;! The pulp tank is set to 1 (3 additionally contains-optical end point detection / shell J device 2 6 which is a window (v i e w

wind〇W) 28 to sense the light emitted by the plasma and detect the VleW trend to determine the end of the etching. When the etching end point is reached, the light and end point detector 26 will send an end point detection signal to the control cry 29 = to turn off the generator 24 by the controller, and then stop the whole process. However, this is not suitable for the $,, r & etch-to-I process with a small cross-sectional area, because the electropolymerized worms produced by the plasma that senses the small holes are small and very difficult to distinguish. The wavelength change of the leading line is too [Invention Summary] In view of this, the present invention proposes a method A for monitoring the status of the drying process, in particular, a method for utilizing the intensity of the two-gamma range of the plasma strength to make Operators can test debt at any time =

530351 V. Description of the invention (3) _ Intensity monitoring results to adjust related parameters to make a profit. The present invention provides a method for detecting the status of plasma using the strength of the plasma, and using the time mode to manage it. Ί: Dry; the process of engraving includes the steps of: (a) placing the wafer on a wafer In the dry etching device of the dry etching tester; (b) Set _ eight plasma intensity detection strength from the private # · ", # remaining time parameters and an electric plasma (chemical monitoring during this time Mortar Λ degree detection intensity detection value curve; and (f) when ^ water is used to wait for a plasma to be slurried, so that the dry etching device continues to connect to "system: body: continuous, judge the ^ gas * It is completely electro-polymerized, and the next process is stopped when the initial value of the second degree is reached, and the dry etching device is sent to the device t. Also, Shen said that the present invention provides a method to detect the dry state; ΓΓΓ1 mode to Drying process of a wafer-the initial value of the plasma strength, and using a thunder will: electricity: engraving the plasma during the time parameter and the time parameter, and ς to: = :: 'is characterized by: comparison The detection value of the intensity of the plasma is determined by: the initial value of the intensity of the piano-water, when the detection value of the intensity of the plasma When # 二 = plasma "is the initial value, the process of making the chest device follow the second step is the opposite. When the plasma strength is less than the set value = 小于 Page 6 0503-6826TW (N); TSMC2001-〇 736 ； Jacky.ptd 530351 V. Description of the invention (4) Cheng, ΐ t ί ί, makes the dry surname engraving stop the next private manufacturing and the dry etching device issues a warning message. Examples:: Figure 2 shows that the plasma etching device 32 used in the present invention does not: Ϊ. The plasma etching device 30 of the present invention includes an etching reaction input. An upper electrode plate 34 and a lower electrode plate 36 are provided. A gas system is connected to the top of the reactor 32, the gas exhaust pipe 42 is connected to the bottom of the plate 32, and the bottom of the reactor 32 is connected. An RF generator 44 is connected to the upper electrode = 3 = connected and a controller 49 is used. To control the opening / closing of the rf generator 44 and at least one etching time parameter I and a plasma intensity starting value T (thresh〇ld 〇f plasma) are set in the controller 49, it is emphasized here that If there are multiple = steps in the etching process, each step corresponds to a time parameter t and a set time. The initial value of taxi water strength is τ, and the #etch gas that is passed into the etching reactor 32 at each step may be different. Other conditions such as concentration, temperature, and pressure may of course be different. The etching time parameter is seven The initial value τ of the electric water intensity is set according to the experience value of each manufacturer, and is not limited here.

^ Refer to FIG. 2 again. During the plasma etching process, a wafer 3 8 is placed on the lower electrode plate 36 in the etching reactor 32, and a plasma is generated by the gas input tube 4 / the input etching gas. p. The thin film deposition layer on the surface of the wafer 38 can be etched. In addition, the plasma etching device 30 also includes a plasma intensity detector 46, which senses the light emitted by the plasma through a view window 48 on the side of the etching reactor 32.

530351 V. Description of the invention (5) Line strength, and converted into plasma strength, and in each period of time parameter ⑴, t2 or t3), an electro-forging strength-time curve graph (as shown in Figure 6) (Shown) to monitor whether the plasma in the etch reactor 32 is a little bit difficult and whether the etching process is normal. When the plasma intensity is abnormal (for example, the maximum plasma intensity detection value s is less than the set plasma intensity initial value τ), the plasma intensity detector 46 sends a signal to the controller 49 In the process, the plasma etching device 30 sends a warning signal (a 1 arm), and the controller 49 turns off the RF generator 44 to stop the entire plasma etching process. Otherwise, the process continues. The dry etching apparatus 30 used in this embodiment is, for example, a lam-9100 type dry-etching machine manufactured by Colin LAM Research. Please refer to FIG. 3 ', which shows a schematic cross-sectional view of a dry etching process according to an embodiment of the present invention. In this embodiment, a dry etching of a contact hole with a small cross-sectional area (for example, the cross-sectional area occupies only 5% of the upper surface area) is taken as an example, but it is not limited to the present invention. That is, any dry etching process can be applied to the present invention. The symbol 38 indicates a wafer. Reference numeral 300 denotes a semiconductor substrate, which may have elements such as MOS (not shown). The symbol 3 1 0 indicates an insulating layer, for example, a Si 2 layer, which is formed on the surface of the substrate 300. The symbol 3 2 0 represents a patterned photoresist layer 'coated on the insulating layer 31 0 and having a small cross-sectional area of the hole 3 3 0' to expose a portion of the insulating layer 31 0 where a contact hole is to be formed. s surface. Then, the wafer 38 is placed in a dry etching apparatus as shown in FIG. 2. First, a plasma-1 340 (for example, a plasma etching gas of CHF3 + inert gas) is used as the insulating layer 3 1 0. For the dry rice engraving, the time parameter for the rest of this step is set to 11.

0503-6826TWF (N); TSMC2001-0736; Jacky.ptd page 8 530351 V. Description of the invention (6) Connection 2 ′ Please refer to FIG. 4, which shows a dry cut of the embodiment of the present invention. After the plasma -1 340 is used to partially dry the insulation layer for 0 days, the contact hole 430 is formed, and then the photoresist layer is removed with plasma-2 440 (such as plasma etching gas of 疋 〇2). 3 2 0. In this step, the narration time parameter is set to 12. ^ After 4 ′, please refer to FIG. 5, which is a schematic cross-sectional view of the dry-cut ^ process of the embodiment of the present invention. After removing the photoresist layer by the plasma-2 440, the plasma-etching gas of plasma-3 540 (for example, SiC14) is used to remove the substrate 300 which is located at the bottom of the contact hole 430 a little. The etching time parameter used to ensure the removal of the step that may remain in the contact hole 430 at this step is set to "$ 310 310s. See Figure 6, which shows the corresponding process of the embodiment of the present invention, the intensity i The time parameter curve is engraved. The symbol! Area refers to the step of performing electrodoping ^ 40, and the etching time parameter set in this step is tl. The area of No. II refers to the step of performing plasma-2 440, and this step The set etching time parameter is ". The symbol π area refers to the step of plasma_3 54〇, and the etching time set in this step can be seen from Fig. 6. In each step, the dry etching device 30 The etching gas' first reaches Φ at the beginning. It is greater than the initial plasma intensity iT (1/9 / WI ★. It is necessary to have no production value S (l / 2 / U, ten Hushangdingxi 42)) or The equivalent plasma intensity value S (1: 2/3) is the only confirmation that the etching gas has been changed. In each step of the etching process, outside of Erfan 70 Wang electric water (peak), the plasma intensity is mostly shown in parallel. Α is loud. It takes a little time for the machine to start. In the cause] 孓 heat engine, and in order to reach

530351 V. Description of the invention (7) Electropolymerization is stabilized and there is this after the spike. The initial value of the plasma intensity T1 set in the system in the region I from point S1 onwards is the whole stage of plasma intensity detection. Compare the starting values of the curve T 2 and T 3. However, in order to construct the complete III), the dry etching gas introduced in the present invention is used, so when the plasma intensity detection value of the plasma intensity detector is less than the set value, the plasma intensity detector 46 will This will cause the plasma etching device 30 to issue a warning to shut down the RF generator 44 and stop the whole person from adjusting the process parameters, such as pressure. Of course, if the operator finds that the curve stops the process and adjusts it to avoid conversely, when the plasma intensity detection value of the plasma intensity detector P is greater than or | value T (1/2/3), then Make the dry money engraving range 0 a short arc to become a parallel line, because the t-plasma intensity detection curve can be compared with it. As for the π and III areas, it can be grounded with the set plasma strength to ensure that in each step (Ι / ιι / At any time, indeed, the initial value of the plasma strength T (ι / 2/3) of the electropolymerization p in the reaction chamber 32 was found by the plasma 46 to transmit a signal to the controller 49. And by using the controller 49 to close the plasma plasma process. To notify the operation, gas flow, temperature, etc. of any abnormalities, you can also immediately stop the chip due to process errors and damage. Detector 4 6 found a reaction The electricity in the cavity 3 2 [at the set plasma intensity starting device 3 0 continues to the next production

This is to emphasize again that the monitoring plasma strength detection value s of the present invention further includes comparing any one of the work / not only comparing the maximum value with the set plasma strength initial value T'j,实 实 Supervisory # 用 时 门 桓 彳 的 洪 ^ ί / Λ 'in order to be 100% compatible with all processes of time-dried dry etching using solitary control. Compared with the conventional technology, the present invention describes Depilation sk for a monitored dry etching process

530351 V. Description of the invention (8) _ The wafer 38 is dry-etched; ::: mode (etching time parameter 7) is set to an etching in the -crystal path; gate: J wide-etching device 30, in the dry etching system Use -density of the plasma to detect the plasma P, and get a value of T during the parameter t between the etch% and the plasma strength. When the plasma strength is detected, the plasma strength is 0. Initial value When the initial value T, make 哕 r shoes j or equal to the plasma strength set; conversely, when the electro-polymerization strength = κ thief no: the detection value is less than $ ^ a,, M1J „ „Rc ^ ^ ^ £ 3〇 ^ ^ and alert the dry etching device 30. In the next process, from the above, we can see that this monitor monitors the intensity detection value based on the time mode. As a rule, it is impossible to grasp the time and privacy to make the operator no longer look like the situation. The present invention can make the actual conditions of the dry etching process of the two parts at any time, and reduce the actual status of the remaining etching process; the dry two = time mode has a considerable contribution to the monitoring of the dry process. X airy mistake, dry etching Although the present invention has been limited to the present invention by a preferred embodiment, anyone skilled in this art should not use it within the scope, but it can be slightly modified and improved. = Without departing from the spirit and scope of the present invention, the attached patent application should be regarded as the only one. Therefore, the protection defined by the present invention shall prevail.

530351 Brief Description of Drawings Figure 1 is a schematic diagram showing a conventional plasma etching apparatus. Fig. 2 is a schematic view showing a plasma etching apparatus used in the present invention. FIG. 3 is a schematic cross-sectional view showing a manufacturing process according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a manufacturing process according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing a manufacturing process according to an embodiment of the present invention. FIG. 6 is a graph showing a plasma strength-etch time parameter corresponding to the manufacturing process of the embodiment of the present invention. [Symbol description] 10, 30 ~ Plasma etching device; 1 2, 3 2 ~ Etching reactor; 14, 34 ~ Upper electrode plate; 18, 38 ~ Wafer, 1 6, 3 6 ~ Lower electrode plate; P ~ Plasma;. 20, 40 ~ gas input pipe; 22, 42 ~ gas exhaust pipe; 2 6 ~ optical endpoint detector; 24, 44 ~ RF generator; 2 9, 4 9 ~ controller; 2 8, 4 8 ~ window; 4 6 ~ plasma strength detector; 300 ~ semiconductor substrate; 3 1 0, 3 1 0 '~ insulating layer;

0503-6826TWF (N); TSMC2001-0736; Jacky.ptd Page 12 530351 The diagram briefly explains 3 2 0 ~ photoresist layer; 3 3 0 ~ hole with small cross-sectional area; 340 ~ plasma-1; 430 ~ contact Holes; 440 ~ plasma-2; 540 ~ plasma-3; SI, S2, S3 ~ the maximum detection value of the plasma strength of each step (I / II / III); ΤΙ, T2, T3 ~ each step (I / I I / III), the initial value of the plasma strength is set; the etching time parameter of each step (I / II / III) is 11, 12, 13 ~

0503-6826TWF (N); TSMC2001-0736; Jacky.ptd page 13

Claims (1)

53〇35i The method is to control the state of the etching process process ☆, and use the time mode to perform a dry etching process on a positive film. The steps include: placing the central film and placing the film on the surface. (B) Set an etching time parameter and a plasma strength initial value; (c) Pass an etching gas into the etching device; (d) Plasma the etching gas to form an electrode (E) using a plasma strength detector to monitor the plasma strength during the remaining time parameter period to obtain a plasma strength detection value curve; and (f) When the detected value of the plasma intensity is greater than or equal to the set initial value of the plasma intensity ', it is judged that the etching gas is indeed plasmatized; when the detected value of the plasma intensity is less than the set value When the initial value of the plasma strength is determined, the gas is not completely plasmatized at this moment. 2 · The method for monitoring the status of a dry etching process as described in item 1 of the scope of the patent application, wherein after determining that the etching gas has not been completely plasmatized, the method further includes stopping the etching apparatus from the dry etching process and causing the etching Device sends an alert. x 3 · The method of monitoring the dry etching process status and material steps described in item 1 of the scope of the patent application, wherein when the wafer further includes a plurality of non-films / layers, the respective films / layers The dry etching processes are performed corresponding to the above (a) to (f). 4 · The method for monitoring the status of a dry etching process as described in item 3 of the scope of the patent application, wherein after determining that the etching gas has not been completely plasmatized, the method further includes stopping the etching apparatus and causing the etching Device 0503-6826TW (N); TSMC2001-0736; Jacky.ptd Page 14 530351 6. Scope of patent application A warning is issued. HIIIll 0503-6826TWF (N); TSMC2001-0736; Jacky.ptd page 15