Conformality Characterization of 3D Thin Films
Dr. Mikko Utriainen – Chipmetrics
Dr. Mikko Utriainen is an ALD pioneer since 1990s and CEO of Chipmetrics Ltd since 2020. His talk describes Chipmetrics’ PillarHall® Test Chip platform for characterisation of thin film conformality. He also emphasizes some its recent use cases and insights in 3D thin film deposition development.
0:00:02 Ladies and gentlemen, thank you for interest to hear my talk and presentation in this advanced 0:00:08 surface engineering summit. That's all. Even in 2021 I am Mikko Utriainen from Chipmetrics and this 0:00:18 presentation, it's about the con formal characterization of three dimensional thin films in the way 0:00:25 we do that by cheap metrics. 0:00:29 Right chip metrics background is an L. D. Atomic layer deposition and especially its strong research 0:00:38 background in Finland. Since 19 eighties. L. D. Was invented in Finland by dr thomas Angela who also 0:00:48 received Millennium Technology. Price of that achievement. 0:00:57 The key benefit of ale the confirm multiple films, confirmable deposition capability boosts more 0:01:04 challenging three dimensional designs with a better performance, an energy efficiency. And this is 0:01:11 especially the case in semiconductor industry which is the main industrial branch of Eld. Yeah, khan 0:01:21 formality means ability to cover three dimensional object uniformly with the same thickness and 0:01:31 properties all over. 0:01:35 Typical. For confirmable, the covered object is that is everywhere is similar thickness. Also in a 0:01:44 deep cavities and insight uh structures of the object. Non conform. Als is the case typically when 0:01:56 that in film deposition is directional and that's not the case with Ellie. Mhm. Then the case is 0:02:05 when we are talking about partial corn formal uh deposition results, those are key interesting 0:02:15 things. So what is the limiting factor in those cases? It can be defusing for example, or it can be 0:02:23 a chemical reactions sticking to represent and so on, which influences on the con formality. This is 0:02:31 actually not so well known thing. And one reason is that there is no hasn't been a very clear way of 0:02:40 standard last way to measure, but property aspect ratio is typically used. It's very useful to 0:02:50 define the chairman trees. Uh and that's a picture here explains how the chairman trees can be 0:02:57 explained. Aspect ratio is a ratio between length and with in this kind of a similar a simple 0:03:05 structures shown in the picture, pictures taken from recent uh review article of L. D. Conn 0:03:13 formality by christmas pattern and don't open, which was published in the two years ago in Applied 0:03:19 Physics Review. Mhm. In according to that uh they have found that a very comprehensive literature 0:03:27 survey there that the record uh record aspect ratio reached in uh for us as a con formalities 7000. 0:03:38 Mhm. In uh typically memory devices, three demands on three dimensional memory devices, aspect races 0:03:45 are in the range of 100 or more Protective code, things with more complex and more microscopic 0:03:53 structures has the biggest aspect races may be in the range of 10. Just good. I guess the future 0:04:00 looks bright. There is more coming applications in treating truth especially true to the three 0:04:06 dimensional being authorization and that related activities. And also of course across materials. 0:04:20 The major problem is methodology. Three dimensional metrology for three dimensional object needs 0:04:26 always cross sectioning and especially when vertical high aspect ratio uh structures are in the 0:04:35 world which are of course typical in in for example in the chemical industry. Yeah, they need uh 0:04:43 challenging sample preparation by force I have been watching for example, or uh expensive and 0:04:51 challenging analytical tools uh which requires specialist users. Uh overall it's very slow to get 0:04:59 the data and sometimes it can take even weeks to get the, get the data from the measurement. Nobody 0:05:06 wants to wait so long. Another problem is the structures, three dimensional strict structures are 0:05:12 not very well accessible. Uh And of course you need some test structure when this question is to 0:05:20 study it in the film, thin film requires some substrate where you deposit in order to study it. Yeah. 0:05:28 And there for example, vertical uh edged trans structures are typically dimensionally inaccurate 0:05:38 cones. Mhm And once destructs us brings kind of an additional parameter, there comes more problems 0:05:53 because the parameter space is already huge. When you are developing 10 films, it can take time to 0:06:02 get the experiment done. There is a lot of uh parameters involved like producers, uh carriers, gases, 0:06:12 conditions, temperatures, time factors also see with the L. D. All kind of new kind of uh 0:06:22 technologies are involved and you have to study those as well from the beginning. Probably all the 0:06:27 material space it's used. It would be so much better if there is some, some standards to live less 0:06:36 attention to test structure geometry itself. 0:06:46 Namely this is old statement from Lord kelvin. If you can't measure it, you can't improve it. You 0:06:54 can also extend that so that if something takes so much time, it also needs that your improvement 0:07:02 will take a lot of time. So some improvements are needed. 0:07:09 Our solution is Product Ized lateral high aspect rations the structures on silicon chips. These 0:07:20 characteristics here is that instead of vertically oriented high aspect ratio structure, this is 0:07:28 simple geometry, but laterally surface plane oriented, high aspect ratio structure, I have a video. 0:07:39 I will show you a little bit more details about it. 0:07:44 Mhm. 0:07:47 So, pillar hall is a silicon test ship made in memes based technology processes. It's the size of 0:07:55 the cheapest 15 times 15 millimeters. It contains multiple of different structure elements all over 0:08:03 to chip. The main LHR structure area is pretty large, contains 19 lateral highest penetration. The 0:08:11 structures from 2 to 1 World. For high aspect ratios of the 10,000. This is showing how the, how it 0:08:23 looks like uh a there's a cavity under the membrane, large area like a Pillar Hall. Indeed, the idea 0:08:34 is that user deposits to fulfillment in their experiments on this structure for further analysis has 0:08:44 shown here. 0:09:07 Mm. Mhm. Mhm. 0:09:25 Typical users are employing it in a way for processes by the one chip on carried away for her 0:09:36 multiple chips on the it's also on what they go to cross auditory. 0:09:47 Mm. 0:09:55 So let me go through once more to pillar hall standard use procedure. Uh So the deposition 0:10:02 experiment is the first step there. Ah The chip is it typically used on as a single chip on the 0:10:10 center of the waiver as a carrier wave for or it can be multiple chips on on one of them in the 0:10:18 center of carrier way for an arrest of them in edge areas and then loading this uh way for three 0:10:26 times deposition system. Second step after after unloading the chip and away from from the from the 0:10:34 chamber. Is the before going to the measurement is the, is the step to remove the top membrane and 0:10:42 that's done by adhesive tape. It's very easy and fun. Part of these things to do 0:10:50 then uh the next step is metrology measurement and that's where the idea and the major idea is to 0:10:58 gain the film penetration depth profile. That there is optical tools which are most typically used 0:11:08 very eh pissant also reflect a meter line scanner has been our uh favorable tool for for many years 0:11:19 already. Typically you need a spot size, preferably less than 10 migrants. Ellipse emitter is very 0:11:28 efficient tool also and especially if your film thickness is less than let's say 30 nm or so. It's 0:11:37 practically the most and only efficient tool. But the spot size are typically a little bit larger 0:11:44 and that means that there is some uh lateral resolution challenges in some cases with the help 0:11:53 senator and then very efficient tool actually optical microscope where we have a better lab tension 0:12:01 recently. 0:12:07 So our chip metrics analysis services available for microscope image analyzes. That means that you 0:12:14 user take uh microscope image of the pillar hall test ship and then we can help you to to get 0:12:24 extract the data penetration film penetration that profile out from these pictures pillar healthy 0:12:32 chip contents, many markers which are utilized in this image analyzes as some there. 0:12:41 And finally uh final step is to extract some confirm malitI numbers and that's uh proposed by 0:12:49 Professor Peron and and others is a P 50 meaning penetration depth 50% for the film thickness from 0:12:57 the beginning of the cavity, opening to the to the entering through the deeper into the in the 0:13:06 cavity. So this is related to this direct measurement is uh in micrometers or meters and that's ah 0:13:19 turned two dimensional is distance as aspect ratio to related by dividing the method linked by gap 0:13:31 height, which is constant 500 nanometers in the case of pillar hall test ship. 0:13:40 one interesting and uh opportunity is to measure wafer level con formality in that case ah because 0:13:50 it's more relative data set than experimental to experimental comparison. This uh is easily allowed 0:13:59 by microscope image analyzes. We have made this experiment with already last year, uh continue these 0:14:07 experiments and uh this development all the time. Two Create a real uh upper level con formality 0:14:17 mapping opportunity. Already we can say that they're using p. d. 50 values. Uh it is uh more 0:14:25 sensitive measure of wafer level uniformity than is the conventional thickness mapping 0:14:36 another future which is actually quite unknown future for the researcher and our our customers. Is 0:14:45 that the directional deposition study opportunities with the pillar hall? Let's our 4th test ship. 0:14:52 Namely there's several futures which should be paid paid attention to two namely vertical. We have 0:15:01 also vertical high aspect rations referenced structures. We wouldn't call those as high expectation 0:15:08 they are or other low expectation structures, but very valuable also for if there is a directional 0:15:18 components in deposition. Yeah. Then uh because of the design of the chip, there is uh cheapside 0:15:28 structures and 0:15:33 here are the cheapside structures. And then because there is a mirror type of opening from the 0:15:43 opening for both direction is a similar high aspect ratio destruction. There's multiple of them, 0:15:49 meaning that in all these compass directions, uh you can find directional dependencies. 0:16:02 Then ah 0:16:06 Two other features related to directional deposition is the uh there is 2 240 aspiration structures 0:16:15 here and here located like that. And Difference is that this opening area with is significantly 0:16:26 different. It's only five microns here where 70 microns here and that's also gives some idea that 0:16:34 they directional deposition is having any influences. Notice that in plasma processes it can typical. 0:16:42 It is indeed. So that there is, there is this kind of directional dependencies and and those 0:16:50 components uh could have an effect on different ways to the different tree dimensional structures. 0:16:58 And I'll ask. But at least it's also initial design of the ship was uh was as an idea that that 0:17:06 there is a cross section taking here. Keeping sorry, keeping this cheap in vertical position in the 0:17:13 chamber. You can get the direction directional deposition from from here, meaning that you have a 0:17:21 very long vertical high aspect ratio cavity. So so far there has nobody used in academic Russia. 0:17:30 It's these features yet. So you are welcome to utilize them. 0:17:42 And there is plenty of academic research papers of pillar usually using pillar hall for example in 0:17:51 the of course inhaled but also in CVD analyzing the properties of the teen film from the side walls. 0:18:00 Me 0:18:04 carrying out the sticking coefficient calculations and physical modeling, Getting more understanding 0:18:11 of corn formality especially in that respect. I would like to pay attention to plus my L. D. 0:18:19 Processes which are surprisingly con formal when radical parts without irons or considered. This is 0:18:31 kind of a new information and that was that was created by by a group of Technical university and 0:18:39 how often a group of urban castles and especially scientist Carson arts has been pre active in in 0:18:49 that research. 0:18:53 There is a list of uh, our reverence articles in pillar hall dot com. Web page. Please take a look 0:19:02 look the reference papers from there. 0:19:09 So treatment X product is Pillar Hall elects are for desk chip, 0:19:16 we offer it as a Packages containing five chips in vacuum really stray, very safe handling and also 0:19:25 as the chips on the diced paper, its contents about 50 chips. Manufacturing is carried out on 150 MB 0:19:33 papers and it's carried out in a micro nova is for Finland. We have a lot of chips in our inventory 0:19:43 and we can serve customers with the fast deliveries, 0:19:49 cheap metrics is a start up company. We are open for cooperation and networking with other entities. 0:19:57 And we have main interest is to develop new cheap metrics applications meaning not pillar hall but 0:20:04 new chip with metrics, you know. And then for pillar Hall we are interested of uh paper use 0:20:13 methodology, combinations of other uh other sources and and then also how this data can be used in 0:20:21 machine learning type of approach is in process control and monitoring. All right. Yeah. 0:20:32 Well this presentation is now coming to the end and it's time to acknowledge so especially our co 0:20:43 developers since many years and from the beginning inventor of Pillar Hall Professor Pick Rick. 0:20:50 Warren is the is the major person to be acknowledged then my partners and ship metrics Van Gogh and 0:20:59 prosecuted then and all we did the colleagues from the past oil therapy, Mark Murray as well. We 0:21:08 have had many and we had a fortunate to have many research collaborators and pilot users V. D. T. I 0:21:16 hope in front of our I. P. M. Salto Inter Molecular and many more gratefully acknowledged as well 0:21:23 and last but not least especially acknowledging all our customers and all l community For sale Inter 0:21:34 Vision with us. Accelerating applications of confirmable three dimensional 10 films. 0:21:45 So thank you very much for your attention and for your interest pillar hall to confirm all 0:21:53 depositions and How to measure taken formality of 10 films. I hope you have received some helpful 0:22:02 information. I'm available as uh as this contact information here tells you you can either contact 0:22:13 me directly um if and when there is uh questions and answer session after this record pre recorded 0:22:25 uh presentation. I'm happy to answer for your requests. 0:22:33 Otherwise I wish you all the best and have a nice summer and stay safe and healthy. Thank you. 0:22:40 Goodbye.