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.