Yes, as soon as you enter a Swiss motorway or expressway a valid vignette is required. Driving even 1km or 1 minute without a valid vignette can result in a heavy fine.
Related articles:
Where can I buy the Swiss motorway vignette?
How much does the Swiss Motorway Vignette cost?
How long is the Swiss motorway vignette valid?
Are shorter term Swiss motorway vignettes available (daily/weekly/monthy)?