A method for determining Q-time of SACVD thin films

Abstract

The present invention provides a method for determining the Q-time of a SACVD film, the method comprising: after preparing a film using SACVD, performing a first stress test on the film, and placing the film in an inert atmosphere environment for a first rest after completion; performing a second stress test after the first rest, and placing the film in an inert atmosphere environment for a second rest after completion; performing a third stress test after the second rest, and placing the film in an inert atmosphere environment for a third rest after completion; performing an Nth stress test after the nth rest, where n≥2 and N≥3; after the Nth stress test, drawing a stress-time curve, and determining Q-time based on the curve. The method can quantify the Q-time of a SACVD film, accurately determine the value of Q-time, and thereby guide the processing timing of the SACVD film, avoid failure of the SACVD film during the production process, improve production efficiency, and reduce production costs.

Description

Technical Field

[0001] The invention belongs to the field of film testing and relates to a method for determining the Q-time of a SACVD film. Background Art

[0002] SA USG / BPSG is widely used as the first physical medium related sublayer and metal interlayer dielectric layer in integrated circuit manufacturing. The original ordered network structure of silicon dioxide is due to boron phosphorus impurities (B 2 O 3 , P 2 O 5 ) is added to make it loose, and it has the ability to flow like liquid to some extent under high temperature conditions. Therefore, the BPSG film has excellent hole filling ability and can improve the flatness of the entire silicon wafer surface, thereby providing a wider process range for lithography and post-processing. However, because the USG / BPSG film is loose and porous, it will quickly absorb water and cause large deviations in film performance when exposed to air for a long time. Therefore, the USG / BPSG film must be processed in a short time. At present, the industry has not clearly defined this "short time (Q-time)". If the Q-time is too long, the film will fail, and if it is too short, it will cause delays in continuous shipments of machines and increase downtime costs. Summary of the invention

[0003] In order to solve the above technical problems, the present application provides a method for determining the Q-time of the SACVD film. This method can quantify the Q-time of the SACVD film and accurately determine the value of the Q-time, thereby guiding the processing timing of the SACVD film, avoiding failure of the SACVD film during the production process, improving production efficiency and reducing production costs.

[0004] In order to achieve the above technical effects, the present invention adopts the following technical solutions.

[0005] The present invention provides a method for determining the Q-time of a SACVD (sub-atmospheric pressure chemical vapor deposition) film, the method comprising:

[0006] (1) After the film is prepared by SACVD, the film is subjected to a first stress test, and after completion, the film is placed in an inert atmosphere environment for a first static state;

[0007] (2) After the first resting state, a second stress test is performed, and after completion, the film is placed in an inert atmosphere environment for a second resting state;

[0008] (3) After the second resting, a third stress test is performed, and after completion, the film is placed in an inert atmosphere environment for a third resting;

[0009] Similarly, after the nth static state, the Nth stress test is performed, n≥2, N≥3; after the Nth stress test, a stress versus time curve is drawn, and Q-time is determined based on the curve;

[0010] The method for determining Q-time according to the curve includes determining the time corresponding to the stress fluctuation of ±20MPa as Q-time according to the stress change data under different static times.

[0011] As a preferred technical solution of the present invention, the film prepared by SACVD includes SA USG (undoped silicate glass) film or SA BPSG (boron phospho-silicate glass) film.

[0012] As a preferred technical solution of the present invention, after the film is prepared, the film is immediately subjected to a first stress test. The first stress test corresponds to a time t 1 =0.

[0013] As a preferred technical solution of the present invention, the inert atmosphere includes any one of nitrogen, argon or helium, or a combination of at least two of them.

[0014] As a preferred technical solution of the present invention, record the first static time τ 1 , the time t corresponding to the second stress test 2 =τ 1 .

[0015] As a preferred technical solution of the present invention, record the second static time τ 2 , the time t corresponding to the third stress test 3 =τ 1+ τ 2 .

[0016] As a preferred technical solution of the present invention, record the nth static time τ n , the time t corresponding to the Nth stress test N =τ 1+ τ 2+……+ τ n .

[0017] As a preferred technical solution of the present invention, the stress testing methods used in the first stress test to the Nth stress test are the same.

[0018] As a preferred technical solution of the present invention, the inert atmosphere environment from the first standing to the nth standing is the same.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects.

[0020] The present invention provides a method for determining the Q-time of a SACVD film. The method can quantify the Q-time of the SACVD film and accurately determine the value of the Q-time, thereby guiding the processing timing of the SACVD film, avoiding failure of the SACVD film during the production process, improving production efficiency, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The stress test results in Example 1 of the present invention and the stress variation curve plotted against the corresponding time are shown.

[0022] Figure 2 The stress test results in Example 3 of the present invention and the stress variation curve plotted against the corresponding time are shown.

[0023] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0024] The technical solution of the present application is further described below through specific implementation methods.

[0025] A specific embodiment of the present invention provides a method for determining the Q-time of a SACVD film, the method comprising:

[0026] (1) After the film is prepared by SACVD, the film is subjected to a first stress test, and after completion, the film is placed in an inert atmosphere environment for a first static state;

[0027] (2) After the first resting state, a second stress test is performed, and after completion, the film is placed in an inert atmosphere environment for a second resting state;

[0028] (3) After the second resting state, a third stress test is performed. After completion, the film is placed in an inert atmosphere environment for a third resting state.

[0029] Similarly, after the nth resting, the Nth stress test is performed, n≥2, N≥3; after the Nth stress test, a stress versus time curve is plotted, and the Q-time is determined based on the curve.

[0030] The method for determining Q-time according to the curve includes determining the time corresponding to the stress fluctuation of ±20MPa as Q-time according to the stress change data under different static times.

[0031] Among them, n can be 2, 3, 4, 5, 6, 7, 8, 9 or 10, etc., and N can be 3, 4, 5, 6, 7, 8, 9 or 10, etc., but are not limited to the above-mentioned values. Other values ​​not listed within the above-mentioned numerical ranges are also applicable.

[0032] In the present invention, the stress of the prepared SACVD film is tested over time to obtain a stress-over-time curve, thereby determining the failure time of the SACVD film through the stress change, and then determining the specific time of Q-time. During each stress test interval, the film is placed in an inert atmosphere environment to ensure that the film does not fail outside the test time, thereby improving the test accuracy.

[0033] In a specific embodiment of the present invention, the conditions for preparing the SA USG film or SA BPSG film by SACVD can be adjusted according to the preparation requirements so that the SA USG film and the SA BPSG film have a loose porous structure, which is not specifically limited herein.

[0034] In a specific embodiment of the present invention, the number of static and stress tests can be adjusted according to the different films to be tested, but it is necessary to ensure that no failure of the SACVD film occurs during the process based on the stress test results.

[0035] In a specific embodiment of the present invention, after the SACVD film is prepared, the film is immediately sent to a stress testing device for testing to avoid the impact of the environment on the SACVD film, so as to accurately obtain the SACVD film stress test result at time 0.

[0036] In a specific embodiment of the present invention, the time corresponding to the stress test result corresponds to the total time the film is left standing in an inert atmosphere. The time required for the stress test is less than 5 min, which is much less than the standing time, so the stress test time is negligible.

[0037] In a specific embodiment of the present invention, the standing time in the inert atmosphere environment can be the same or different. The specific standing time can be adjusted according to the test requirements of different films and is not specifically limited here.

[0038] In one specific embodiment of the present invention, the first static time τ is recorded. 1 , the time t corresponding to the second stress test 2 =τ 1 ; Record the second static time τ 2 , the time t corresponding to the third stress test 3 =τ 1+ τ 2 ; Record the nth static time τ n , the time t corresponding to the Nth stress testN =τ 1+ τ 2+……+ τ n .

[0039] In a specific embodiment of the present invention, the stress testing methods used in the first stress test to the Nth stress test are the same, and the inert atmosphere environments from the first resting state to the nth resting state are the same, so as to avoid test errors caused by differences in test methods.

[0040] In a specific embodiment of the present invention, a longer standing time can be first used to determine a wider Q-time time range for a test sample; then, using the same sample, test conditions and standing environment, the standing time can be shortened within the wider Q-time time range to further accurately determine the Q-time of the sample.

[0041] In a specific embodiment of the present invention, when the rest time is shortened to a level comparable to the stress test time, resulting in the stress test time being not negligible, the time corresponding to the stress test result can be regarded as the sum of the rest time and the test time.

[0042] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0043] Example 1

[0044] This embodiment provides a method for determining the Q-time of a SACVD film, the method comprising:

[0045] (1) SA USG thin film was prepared by SACVD at a process temperature of 480 °C and a process pressure of 300 torr to obtain a SA USG thin film with a thickness of 600 nm. The first stress test was performed on the film immediately after the preparation was completed. The stress test result was recorded as stress#1. The film was placed in a nitrogen cabinet for the first static state.

[0046] (2) After the first resting time of 30 min, the film was subjected to a second stress test. The stress test result was recorded as stress#2. The film was placed in a nitrogen cabinet for a second resting time.

[0047] (3) After the second resting time of 30 min, the film was subjected to a third stress test. The stress test result was recorded as stress#3. The film was placed in a nitrogen cabinet for the third resting time.

[0048] Similarly, after the third and fourth resting times are each rested for 30 min, and the fifth and sixth resting times are each rested for 60 min, the fourth stress test, the fifth stress test, the sixth stress test, and the seventh stress test are performed in sequence. The stress test results are recorded as stress#4, stress#5, stress#6, and stress#7, respectively. The stress test results and the corresponding time are shown in Table 1. The stress change curve over time is drawn according to the stress test results and the corresponding time, as shown in Figure 1 shown.

[0049] The model of the stress testing device used in the stress test in this embodiment is FSM128.

[0050] Table 1

[0051]

[0052] Example 2

[0053] This embodiment provides a method for determining the Q-time of a SACVD film, the method comprising:

[0054] (1) SA USG thin film was prepared by SACVD at a process temperature of 450 °C and a process pressure of 280 torr to obtain a SA USG thin film with a thickness of 500 nm. The first stress test was performed on the film immediately after the preparation was completed. The stress test result was recorded as stress#1. The film was placed in a nitrogen cabinet for the first static state.

[0055] (2) After the first resting time of 20 min, the film was subjected to a second stress test. The stress test result was recorded as stress#2. The film was placed in a nitrogen cabinet for a second resting time.

[0056] (3) After the second resting time of 20 min, the film was subjected to a third stress test. The stress test result was recorded as stress#3. The film was placed in a nitrogen cabinet for the third resting time.

[0057] By analogy, after the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth and thirteenth resting times were each rested for 20 min, the fourth stress test, the fifth stress test, the sixth stress test, the seventh stress test, the eighth stress test, the ninth stress test, the tenth stress test, the eleventh stress test, the twelfth stress test, the thirteenth stress test and the fourteenth stress test were carried out in sequence. The stress test results were recorded as stress#4, stress#5, stress#6, stress#7, stress#7, stress#8, stress#9, stress#10, stress#11, stress#12 and stress#13 in sequence. The stress test results and the corresponding times are shown in Table 2. The stress change curve over time is drawn according to the stress test results and the corresponding time.

[0058] The model of the stress testing device used in the stress test in this embodiment is FSM128.

[0059] Table 2

[0060]

[0061] Example 3

[0062] This embodiment provides a method for determining the Q-time of a SACVD film. Except for using SACVD to prepare the SABPSG film, the other conditions are the same as those of Example 1. The stress test results and the corresponding time are shown in Table 3. A stress versus time curve is drawn based on the stress test results and the corresponding time, as shown in Figure 2 shown.

[0063] Table 3

[0064]

[0065] Example 4

[0066] This embodiment provides a method for determining the Q-time of a SACVD film. The test samples, test conditions and static environment of the method are exactly the same as those of Example 3. The only difference is that after the fourth static in Example 3, the static time is shortened, that is, after the fourth static, a static is performed in sequence, with a static time of 15 min, and the test result is recorded as stress#a; b static, with a static time of 15 min, and the test result is recorded as stress#b; c static, with a static time of 15 min, and the test result is recorded as stress#c; d static, with a static time of 15 min, and the test result is recorded as stress#d; and the sixth static in Example 3 is performed to further accurately determine the Q-time. The stress test results and corresponding times are shown in Table 4.

[0067] Table 4

[0068]

[0069] The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed structural features, that is, it does not mean that the present invention must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0070] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0071] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0072] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for determining the Q-time of a SACVD film, characterized in that: The method comprises: (1) After the thin film is prepared by SACVD, a first stress test is performed on the thin film, and after completion, the thin film is placed in an inert atmosphere environment for a first static state; (2) performing a second stress test after the first standing still, and after completion, placing the film in an inert atmosphere environment for a second standing still; (3) performing a third stress test after the second static state, and after completion, placing the film in an inert atmosphere environment for a third static state; After the nth static state, perform the Nth stress test, where n≥2 and N≥3; after the Nth stress test, draw a stress versus time curve, and determine Q-time according to the curve; The method for determining Q-time according to the curve includes determining the time corresponding to the stress fluctuation of ±20MPa as Q-time according to the stress change data under different static times; The film prepared by SACVD includes SA USG film or SA BPSG film; First, a longer standing time is used to determine a wider Q-time range for the test sample; then, the same sample, test conditions and standing environment are used to shorten the standing time within the wider Q-time range to further accurately determine the Q-time of the sample.

2. The method according to claim 1, characterized in that After the film is prepared, a first stress test is immediately performed on the film, and the first stress test corresponds to a time t1=0.

3. The method according to claim 1, characterized in that: The inert atmosphere includes any one of nitrogen, argon or helium, or a combination of at least two of them.

4. The method according to claim 1, characterized in that The first static time τ1 is recorded, and the second stress test corresponds to a time t2=τ1.

5. The method according to claim 4, characterized in that Record the second static time τ2, the time corresponding to the third stress test t3=τ 1+ τ2.

6. The method according to claim 5, characterized in that Record the nth static time τ n , the time t corresponding to the Nth stress test N =τ 1+ τ 2+……+ τ n .

7. The method according to claim 1, characterized in that The stress testing methods used in the first stress test to the Nth stress test are the same.

8. The method according to claim 1, characterized in that The inert atmosphere environments of the first to the nth stillness are the same.

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