Supply Chain Planning Blog

Why Lot Release is So Important in Semiconductor Manufacturing

Posted by Cyrus Hadavi on Thu, Jun 08, 2017

If I arrive on-time or early at the airport but there is a problem with the airplane and a long delay in the scheduled takeoff time, does it get me to my destination on time? Clearly the answer is No! Is it better for me to stay in the comfort of my home and go when I know the plane is ready to take off? Or even better, find another flight to my destination so that I get there on time. By going to the airport at the “wrong time” and waiting I am only increasing “WIP” or waiting time and I am also contributing to airport congestion which adds to the traffic and boarding of other flights possibly causing others to miss their flights.  Such problems can be avoided by an intelligent planner or, release strategy, that can figure out exactly what the right time is for me to leave home given the traffic situation, the speed of cars, the parking time and time it takes to go through security. This kind of predictive planning is ideal for releasing lots in a semiconductor manufacturing line where depending on the mix of products, availability of resources and masks as well as WIP, it can decide which lots should be released and which ones should be held back so that we meet the following three objectives optimally:

  • Cycle time
  • Equipment utilization
  • Delivery performance

The following diagram shows the relationship between these three parameters and how they change with WIP increase. In a high mix environment, increase in WIP does not necessarily imply additional wait times or delay in delivery because of multiple routes and balance of allocation of jobs by the system. The grey shaded area represents optimal region of operation where the desired objectives can be achieved.

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In environments where there is a high mix of products, such as foundries, we can increase the number of lots released without increasing their waiting time by ensuring that they are balanced across different bottleneck equipment such as lithography equipment. Given the complexity of such environments where each process has 400-600 steps using hundreds of equipment requiring anything from 10 minutes to 10 hours with highly sensitive set up times (implanters) or batching requirements (ovens), one has to intelligently look ahead and look behind to ensure proper balance of lots re-entering the process and or entering the process with different priorities.

Unfortunately, sequencing engines with simplistic rules have been given too much attention in order to solve such a complex problem. Through years of R&D, we have concluded that unless a proper release strategy is deployed, sequencing would not be of much value. It is a reactive engine not a preventive one. But more importantly, in the presence of an adequate release strategy, sequencing can be a liability in the sense that it would try to resolve issues locally not being aware of the potential issues it might be causing 50 steps later! Can you imagine being at the gate, and the airline personnel try to sequence your entry into the plane when the plane is not even at the gate or being fixed!

One other myth is the use of simulation tools to plan fabs! Simulation tools look nice and show movement. It is like a video game, we all enjoy watching it. However, they DO NOT PROVIDE a strategy. They only show you where the problem might lie ahead without telling you how to avoid it. How could they? They do not look ahead; by definition simulation is one sequence at a time!

As in our opening example, a good release strategy is aware of the right mix of products in the fab as well as the work load of each equipment, now and future, and is constantly trying to balance what needs to go next such that the bottlenecks, as they are changing, will be fully utilized and at the same time keeping in mind which lots need to be ready and when for on-time delivery. In fact, our research shows that in the presence of a good release strategy, a simple FIFO is the best sequence for the resources. In the context of our airport example, if you left your home at the right time, as you approach your gate, without much waiting, you will show your boarding pass and get into your seat for takeoff.  No need to be sequenced!

Topics: Supply Chain, Supply Chain Planning, Supply Chain Performance Management, Manufacturing Software, Manufacturing Planning, Inventory Optimization, Semiconductor, Factory Planning, Fabrication planning

Monolithic Power Systems Plans With Adexa: News Release

Posted by kameron hadavi on Wed, Apr 06, 2011

Monolithic Power SystemsApril 7, 2011-- Adexa announced today Monolithic Power Systems, a high performance fabless semiconductor company, has selected and are implementing Adexa’s supply chain planning, and demand planning solutions. 

 “Our product portfolio has grown to hundreds of diverse products for worldwide customers, and we interact with multiple Foundries, Assembly and Testing sites.  We turned to advanced information technology solutions to further optimize the whole demand and supply planning process, and to ultimately better service our customers,” stated CEO, Michael Hsing, of Monolithic Power Systems.  

With deployment of the new systems, Monolithic Power Systems expects to further improve visibility, accuracy, and performance optimization in its supply chain, while enhancing collaboration across multiple business units.

“We selected Adexa through a long RFP process involving multiple leading vendors.  Adexa demonstrated very strong expertise in our industry and system implementation, and overall commitment to their customers”, added Dr. Henry Zhao, Director of Global IT of Monolithic Power Systems.

“Semiconductors has always been a big focus for us,” said Cyrus Hadavi, Adexa CEO.  “In the past year we have been seeing strong demand for our planning solutions from the Fabless side of the industry.  We are glad to see this trend continuing into this year as Monolithic Power Systems is being welcomed into our customer base."  

For more information about challenges and planning solutions for the fabless industry, download this ePaper: Overcoming The Shortcomings Of Fabless Planning Systems 

 

About Monolithic Power Systems, Inc.

Monolithic Power Systems (MPS) is a high performance analog semiconductor company headquartered in San Jose, California. Formed in 1997, the company has three core strengths; deep system-level and applications knowledge, strong analog design expertise, and an innovative proprietary process technology. These combined advantages enable MPS to deliver highly integrated monolithic products that offer energy efficient, cost-effective solutions.  Visit: www.monolithicpower.com

Topics: Supply Chain Planning, Demand Planning, Fabless, Semiconductor

Planning Proliferation Of Products In A Fabless World

Posted by kameron hadavi on Wed, Oct 13, 2010

Semiconductor Supply Chain Palnning“Complex” is the common word we hear from many of our Fabless Semiconductor customers in describing their supply chains.  We talked a bit about that in our last blog posting entitled: Fabless Semiconductor Planning: Between a-rock-and a-Hard-place!  In this article, I want to touch on another culprit in complexity of a Fabless enterprises (or Semiconductors in general), proliferation of products

It’s no secrete that Fabless supply chain are faced with ever increasing number of products, and with that comes a lot more part#’s.   It’s one thing to deal with 3 products, and another thing to deal with 30.  The part#’s involved increases exponentially with every end-product.  Imagine this, in most cases our fabless customers are dealing with 100’s of end-products.  This makes crunching through the numbers for a supply chain “plan” very difficult and slow.  Remember, in planning the entire supply chain, these part#’s have to be used for demand planning (when the customers order it), operations planning (how to build it), inventory planning (what to keep on hand), and Supply planning (which suppliers to use and when).   The level of complexity is mind-boggling.

One of the new trends in dealing with this level of complexity is through Attribute Based Planning.  We have written a lot about this in the past but it seems like our readers can’t get enough of it, and for good reason--it works.  Attributes really simplify modeling the entire supply chain by utilizing the “characteristics” of products to describe them, rather than using unique part#.  For example, you may have a grade A, B, and C chips, at speeds of 1.66Ghz, 2.66Ghz, and 3.0Ghz.  You can give all 9 potential combinations a unique product name, or you can have only 3 product names by referring to the attributes of (Grade + Speed).  This is a very simple example, but you can learn a lot more about this by either reading the Attribute Based Planning ePaper or watching the “What is Attribute Based Planning” video on the Supply Chain Planning Channel

You can apply attributes to all levels of planning but there is a catch--your planning system has to be able to handle attributes for the process its intended for.  For example, for Demand Planning, the customer orders have to be described by their attributes within the system.  For Production planning, the product routes have to defined by attributes within the same system, and so on.  Basically, the entire logic and algorithms of your planning system has to be attribute-based, or you are stock with the unique part#’s. 

For fabless companies, who deal with massive product proliferations, attributes will make life a lot easier on your many planners.  They get to collaborate together much faster, and avoid a lot of clutter.   Below, see how Silicon Laboratories is using attributes in their planning environment.  Also, For more information on this topic download: Overcoming The Shortcomings Of Fabless Planning Systems ePaper.

 

Kameron HadaviAbout the Author:  Kameron Hadavi is the Vice President of Marketing & Alliances at Adexa, for more information about him please click here.

Topics: Supply Chain Planning, Demand Planning, Attribute Based Planning, Fabless, Attributes, Semiconductor

Fabless Semiconductor Planning: Between A-Rock-And-A-Hard-Place!

Posted by kameron hadavi on Tue, Oct 12, 2010
Fabless Semiconductor PlanningMost fabless semiconductor companies are stuck between a rock-and-a-hard-place.  On one end, they have big customers demanding what they want, when they want it; and on the other end, they have big suppliers manufacturing their products—some 16 time zones away.    Synchronizing and managing capacities and deliveries through a complex supply chain like this cannot be easy.  Compounding the complexity is the short life-cycle of such products and the long manufacturing lead-times through outsourced Fabs.  With every new product, you basically have to revamp a good part of your supply chain, quickly.    The common theme to all of these challenges is time and uncertainty

Now let’s break the time and uncertainty factors down to their components.  When it comes to manufacturing anything, there is always a Planning cycle-time, and a Manufacturing cycle-time.  The latter, is the pure production time it takes to manufacture a product.  Fabless companies don’t control the manufacturing lead-time, since all of their production is outsourced.  However, they do have the opportunity to manage the suppliers’ capacity that is committed to them—which becomes part of the Planning cycle-time.  They also have to worry about the uncertainty of what they will order with the amount of capacity that they have been promised.  This makes the Planning cycle-time, and accuracy of the plan, twice as important to a fabless enterprise.   Planning cycle-time, is the amount of time a company needs to plan, react, and/or rollout a new plan based on market demand, inventory positions, and supplier capacity commitments.  Its reduction translates into less uncertainty and increased accuracy.  To that end, reducing planning cycle-times is a colossal competitive factor in this market.  Imagine cutting weeks out of your planning lead-times, which would directly impact your customer service, market share, and competitive positioning—amongst other things.  

How can you battle time by achieving shorter lead-times?  Or in terms of fabless, how can you reduce your Planning cycle times and increase plan accuracy?  Before I answer that, let me ask you a question, how can a manufacturer produce goods faster?  The simple answer is: better technology, and faster machines.  The same thing goes for planning systems.  If you want to fundamentally do it faster then you will need a new technology that can help you plan faster, collaborate more, and give you more visibility, thereby enabling better plans.  There are many processes that need to have faster planning times such as demand planning, operations planning, inventory optimization, and of course supply planning.  In picking the right system for your enterprise make sure you consider all these processes and how well the system adheres to your supply chain.   After all what’s the use of faster delivery times, if your inventories and cost is going through the roof.   

Adexa is one of the providers of such technologies and systems, with a great deal of focus on the fabless industry.   Below, one of our fabless customers talks about how they are using our systems to deal with fabless industry's tough challenges.   Also, For more information on this topic download: Overcoming The Shortcomings Of Fabless Planning Systems ePaper.

Kameron HadaviAbout the Author:  Kameron Hadavi is the Vice President of Marketing & Alliances at Adexa, for more information about him please click here.

Topics: Supply Chain Planning, Demand Planning, Inventory Planning, Fabless, Operations Planning, Cycle time, Semiconductor